Security vulnerabilities have been identified in Citrix Virtual Apps and Desktops, and Citrix Workspace app for Windows and Linux. A total of 4 vulnerabilities have been addressed in the latest updates for these Citrix products which if exploited would allow attackers to perform elevation of privileges and take control of the system. These flaws have not yet received a CVSS base score on NIST’s National Vulnerability Database (NVD), however the Cybersecurity and Infrastructure Security Agency (CISA) have issued a security bulletin encouraging users and administrators to apply the latest updates to patch these flaws, suggesting they are of a high severity.  

The first vulnerability tracked as CVE-2023-24483 is found in Citrix Virtual Apps and Desktops. This improper privilege management vulnerability could be exploited by a local attacker to elevate their privilege to NT AUTHORITYSYSTEM on the target Windows VDA. This is the highest access level on Windows, so an attacker who obtains this level of access can perform many actions without restrictions, such as modification of system configurations, executing code, and access to sensitive information. If the target is a part of a network the attacker can also use these elevated privileges to move laterally as well as pivot to adjacent systems.  

Two improper access control vulnerabilities were found in Citrix Workspace app for Windows, the first of which is tracked as CVE-2023-24484. An exploit of this flaw could cause log files to be written to a directory they do not have permission to write to. The second vulnerability in this app is CVE-2023-24485 which if exploited allows for privilege escalation of the attacker on the host system. These two flaws can be exploited together to cause an attacker with standard user privileges to be able to perform operations with SYSTEM level access on the device running the vulnerable Citrix app.  

These Windows vulnerabilities affect Citrix Virtual Apps and Desktops current release versions and Citrix Workspace App for Windows before 2212, and long-term service release versions 2203 before CU2, and 1912 before CU6 (before CU7 Hotfix 2 for Workspace App for Windows). Users of affected versions should update their systems of the Workspace App and Virtual Apps and Desktops to the newest releases in order to apply the official security patch and protect their systems from this flaw. 

 The improper access control vulnerability CVE-2023-24486 was also identified in the Citrix Workspace app for Linux, which affects all versions of this app before 2203. A local attacker can exploit this vulnerability to gain access to another session of Citrix Virtual Apps and Desktops that is being used by a different user on the same device on which the ICA session is launched. This can result in a session takeover of the target session on the vulnerable device. This vulnerability has been patched in the latest release versions for Citrix Workspace app for Linux which can be downloaded from the Citrix website.