Citrix has issued security updates to address a critical authentication bypass flaw in its application delivery controller (ADC) and Gateway products, which could be used to take control of affected systems.
Under certain conditions, successful exploitation of the flaws could allow an adversary to gain authorized access, perform remote desktop takeover, and even circumvent defenses against login brute-force attempts.
- CVE-2022-27510 – Unauthorized access to Gateway user capabilities
- CVE-2022-27513 – Remote desktop takeover via phishing
- CVE-2022-27516 – User login brute-force protection functionality bypass
The flaws affect the following Citrix ADC and Citrix Gateway-supported versions:
- Citrix ADC and Citrix Gateway 13.1 before 13.1-33.47
- Citrix ADC and Citrix Gateway 13.0 before 13.0-88.12
- Citrix ADC and Citrix Gateway 12.1 before 18.104.22.168
- Citrix ADC 12.1-FIPS before 12.1-55.289
- Citrix ADC 12.1-NDcPP before 12.1-55.289
In the case of CVE-2022-27516, however, the exploit relies on the appliances being configured as either a VPN (Gateway) or an authentication, authorization, and accounting (AAA) virtual server.
Furthermore, CVE-2022-27513 and CVE-2022-27516 only apply when the RDP proxy feature and the user lockout functionality “Max Login Attempts” are enabled.
Customers who rely on Citrix-managed cloud services do not need to take any action, according to the cloud computing and virtualization technology company.
The vulnerabilities were discovered and reported by Jarosaw Jahrek Kamiski, a researcher at the Polish penetration testing firm Securitum.
“Affected Citrix ADC and Citrix Gateway customers are advised to install the relevant updated versions of Citrix ADC or Citrix Gateway as soon as possible,” Citrix said in an advisory.