CVE-2023-6917 is a vulnerability identified in the Performance Co-Pilot (PCP) package on Red Hat Enterprise Linux 9, caused by inconsistent privilege separation among systemd services associated with PCP. Some PCP services run under limited PCP user/group privileges, while others operate with full root privileges. This disparity creates a security risk when privileged root processes interact with directories or directory trees owned by unprivileged PCP users. Specifically, the vulnerability involves the creation of temporary files with insecure permissions, which can be exploited through symlink attacks. An attacker with local PCP user privileges could manipulate these temporary files or directories to escalate privileges to root by exploiting the root-privileged services’ interactions with PCP-owned directories. This undermines the isolation intended between PCP users and root, potentially allowing unauthorized access to sensitive system resources. The vulnerability does not require user interaction but does require the attacker to have local access with high privileges (PCP user). The CVSS 3.1 score of 6.0 reflects a medium severity, with high impact on confidentiality and integrity but no impact on availability. No known exploits have been reported in the wild as of the publication date. The root cause is the mixed privilege model and insufficiently secure handling of temporary files and directories within PCP services, highlighting the importance of robust privilege separation and secure file handling in system services.

For European organizations, especially those running Red Hat Enterprise Linux 9 in enterprise, government, or critical infrastructure environments, this vulnerability poses a risk of local privilege escalation. An attacker who gains local PCP user access could exploit this flaw to escalate privileges to root, potentially compromising system confidentiality and integrity. This could lead to unauthorized access to sensitive data, modification of system configurations, or further lateral movement within networks. While the vulnerability does not affect availability directly, the elevated privileges gained could be leveraged to disrupt services or implant persistent threats. Organizations with strict compliance requirements around data protection and system integrity (e.g., GDPR, NIS Directive) may face regulatory and reputational risks if exploited. The requirement for local privileged access limits the attack surface but does not eliminate risk, particularly in environments with multiple users or where insider threats exist.

To mitigate CVE-2023-6917, organizations should: 1) Apply any available patches or updates from Red Hat for the PCP package and related systemd services as soon as they are released. 2) Review and harden the privilege separation configuration of PCP services to ensure consistent and minimal privileges, avoiding root-level access where unnecessary. 3) Audit and restrict local user access to PCP user accounts to trusted administrators only, minimizing the risk of local exploitation. 4) Implement file system permissions and access controls on PCP directories and temporary file locations to prevent unauthorized modifications or symlink creation. 5) Monitor system logs and audit trails for suspicious activity related to PCP services and temporary file operations. 6) Consider deploying host-based intrusion detection systems (HIDS) to detect anomalous behavior indicative of privilege escalation attempts. 7) Educate system administrators about the risks of mixed privilege services and the importance of secure temporary file handling. These steps go beyond generic advice by focusing on privilege management, access control, and proactive monitoring specific to the PCP context.