CVE-2021-35937

A race condition vulnerability was found in rpm. A local unprivileged user could use this flaw to bypass the checks that were introduced in response to CVE-2017-7500 and CVE-2017-7501, potentially gaining root privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• https://access.redhat.com/security/cve/CVE-2021-35937
• https://bugzilla.redhat.com/show_bug.cgi?id=1964125
• https://rpm.org/wiki/Releases/4.18.0
• https://security.gentoo.org/glsa/202210-22
• https://www.usenix.org/legacy/event/sec05/tech/full_papers/borisov/borisov.pdf
• https://access.redhat.com/security/cve/CVE-2021-35937
• https://bugzilla.redhat.com/show_bug.cgi?id=1964125
• https://rpm.org/wiki/Releases/4.18.0
• https://security.gentoo.org/glsa/202210-22
• https://www.usenix.org/legacy/event/sec05/tech/full_papers/borisov/borisov.pdf