PolicyKit INT_MAX UID systemctl Command Execution Vulnerability [CVE-2018-19788]
CVE Number – CVE-2018-19788
A vulnerability in PolicyKit could allow a local attacker to bypass authentication and execute any systemctl command on a targeted system.The vulnerability is due to improper handling of a user identifier (UID) with a value greater than the INT_MAX value on a targeted system. An attacker could exploit this vulnerability by accessing a targeted system and creating a user with a UID value greater than the INT_MAX value. A successful exploit could allow the attacker to bypass authentication and execute any systemctl command on the system, which could be used to conduct further attacks.Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available.PolicyKit has confirmed the vulnerability and released software updates.
Analysis
- To exploit this vulnerability, the attacker must have user-level access to the targeted system. This access requirement could reduce the likelihood of a successful exploit.
Safeguards
- Administrators are advised to apply the appropriate updates.Administrators are advised to allow only trusted users to access local systems.Administrators are advised to allow only privileged users to access administration or management systems.Administrators are advised to monitor critical systems.
Vendor Announcements
- PolicyKit has released an issue report at the following link: Issue #74
Fixed Software
- PolicyKit has released software patches at the following links: Check gid and uid initialization in PolkitUnixUser and Group objects and Allow negative uids/gids in PolkitUnixUser and Group objects
Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.