systemd pam_systemd Privilege Escalation Vulnerability [CVE-2019-3842]

CVE Number – CVE-2019-3842

A vulnerability in systemd could allow a local attacker to gain elevated privileges on a targeted system and execute arbitrary code or cause a denial of service (DoS) condition. The vulnerability is due to the improper sanitization of the environment by the pam_systemd system daemon of the affected software. An attacker could exploit this vulnerability by maliciously setting a XDG_SEAT environment variable on the targeted system. A successful exploit could allow the attacker to gain elevated privileges on the system and execute arbitrary code or cause a DoS condition. The vendor 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 may 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

• The vendor has released a git commit at the following link: commit 83d4ab55336ff8a0643c6aa627b31e351a24040a

Fixed Software

• The vendor has released software updates at the following link: systemd v242