Improper Verification of Cryptographic Signature in Linux kernel - CVE-2021-35039
Published: August 13, 2022
Vulnerability identifier: #VU66477
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-35039
CWE-ID: CWE-347
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to improper signature handling in the kernel/module.c in Linux kernel. If the kernel module is not signed, it still can be loaded into the system via init_module if module.sig_enforce=1 command-line argument is used. As a result, a local user can load unsigned and potentially malicious kernel modules.
How to mitigate CVE-2021-35039
Install updates from vendor's website.
Sources
- https://www.openwall.com/lists/oss-security/2021/07/06/3
- https://github.com/torvalds/linux/commit/0c18f29aae7ce3dadd26d8ee3505d07cc982df75
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.14
- http://www.openwall.com/lists/oss-security/2021/07/06/3
- https://security.netapp.com/advisory/ntap-20210813-0004/
- https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0c18f29aae7ce3dadd26d8ee3505d07cc982df75