Pierluigi Paganini November 21, 2024

Decade-old flaws in the needrestart package in Ubuntu Server could allow local attackers to gain root privileges without user interaction.

The Qualys Threat Research Unit (TRU) discovered five Local Privilege Escalation (LPE) decade-old security vulnerabilities in the needrestart package that could allow a local attacker to gain root privileges without requiring user interaction.

The needrestart package in Ubuntu is a utility designed to ensure system stability after software updates. When packages are updated, especially ones affecting shared libraries or services, it’s often necessary to restart those services or even the entire system for changes to take effect.

The needrestart package is installed by default in Ubuntu Server, starting with version 21.04. The flaws were likely introduced with the interpreter support in needrestart version 0.8, released in April 2014.

The vulnerabilities have been tracked as CVE-2024-48990, CVE-2024-48991, CVE-2024-48992, CVE-2024-10224, and CVE-2024-11003.

These are the descriptions for the flaws:

• CVE-2024-48990 (CVSS score: 7.8) – A vulnerability that allows local attackers to execute arbitrary code as root by tricking needrestart into running the Python interpreter with an attacker-controlled PYTHONPATH environment variable.
• CVE-2024-48991 (CVSS score: 7.8) – A vulnerability that allows local attackers to execute arbitrary code as root by winning a race condition and tricking needrestart into running their own, fake Python interpreter (instead of the system’s real Python interpreter).
• CVE-2024-48992 (CVSS score: 7.8) – A vulnerability that allows local attackers to execute arbitrary code as root by tricking needrestart into running the Ruby interpreter with an attacker-controlled RUBYLIB environment variable.
• CVE-2024-11003 (CVSS score: 7.8) and CVE-2024-10224 (CVSS score: 5.3) – These vulnerabilities allows a local attacker to execute arbitrary shell commands.

The Qualys TRU team has developed functional exploits for disclosed vulnerabilities, warning that they are easily exploitable and may soon see public working exploits.

“These vulnerabilities in the needrestart utility allow local users to escalate their privileges by executing arbitrary code during package installations or upgrades, where needrestart is often run as the root user.” reads the advisory. “An attacker exploiting these vulnerabilities could gain root access, compromising system integrity and security.”

Successful exploitation of these flaws could expose enterprises to severe risks like unauthorized data access, malware, and operational disruptions, leading to breaches, non-compliance, and reputational harm. Immediate mitigation through software updates or disabling the vulnerability is essential.

To prevent the exploitation of the flaw Qualys researchers recommend disabling the interpreter scanning feature in needrestart by modifying its configuration file, typically located at /etc/needrestart/needrestart.conf. Add the line $nrconf{interpscan} = 0; to disable interpreter scanners and block the vulnerability.

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Pierluigi Paganini

(SecurityAffairs – hacking, Ubuntu)