CVE-2020-36770 in ebuild for Slurm
Summary
by MITRE • 01/15/2024
pkg_postinst in the Gentoo ebuild for Slurm through 22.05.3 unnecessarily calls chown to assign root's ownership on files in the live root filesystem. This could be exploited by the slurm user to become the owner of root-owned files.
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Analysis
by VulDB Data Team • 02/03/2024
The vulnerability described in CVE-2020-36770 represents a critical privilege escalation issue within the Gentoo package management system affecting Slurm versions through 22.05.3. This flaw exists in the package installation script known as pkg_postinst which executes during the post-installation phase of the software deployment process. The vulnerability stems from an improper implementation of file ownership assignment that creates an exploitable condition within the system's security model.
The technical flaw manifests when the pkg_postinst script performs an unnecessary chown operation that assigns root ownership to files within the live root filesystem. This operation occurs with elevated privileges during package installation, creating a scenario where the slurm user account can potentially manipulate file ownership relationships. The vulnerability is particularly concerning because it allows a low-privilege user to gain ownership of files that should remain exclusively owned by the root user, effectively undermining the fundamental principle of least privilege that governs Unix-like operating systems.
This vulnerability directly impacts system integrity and can be classified under CWE-276, which addresses improper file permissions and ownership assignments. The operational consequences extend beyond simple privilege escalation as it enables malicious users to modify critical system files that are typically protected from unauthorized access. Attackers can leverage this condition to establish persistent access points within the system, modify system binaries, or manipulate configuration files that control the Slurm workload management system. The attack vector is particularly dangerous because it occurs during legitimate package installation procedures, making it difficult to detect and potentially allowing for stealthy privilege escalation attacks.
The impact of this vulnerability aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits. The slurm user, while normally restricted to its designated operational scope, can exploit this flaw to gain root-level control over specific files within the filesystem. This creates opportunities for attackers to manipulate the Slurm installation itself, potentially compromising job scheduling processes, access controls, and overall cluster security. The vulnerability represents a serious threat to high-performance computing environments where Slurm is commonly deployed, as it could allow unauthorized users to gain complete control over critical computational resources.
Mitigation strategies should focus on immediate patching of the affected Slurm versions, ensuring that package installation scripts properly validate ownership assignments, and implementing proper access controls during package installation processes. System administrators should review existing file ownership assignments and verify that no unauthorized modifications have occurred. The remediation process involves updating to patched versions of Slurm that properly handle file ownership during installation, as well as implementing monitoring procedures to detect unauthorized file ownership changes that may indicate exploitation attempts. Additionally, organizations should consider implementing principle of least privilege controls that restrict the ability of non-root users to manipulate system-critical files even when they possess legitimate access to the Slurm service.