Vulnerability in C-Ares
CVE-2023-31147
c-ares is an asynchronous resolver library. When /dev/urandom or RtlGenRandom() are unavailable, c-ares uses rand() to generate random numbers used for DNS query ids. This is not a CSPRNG, and it is also not seeded by srand() so will generate predictable output. Input from the random number generator is fed into a non-compilant RC4 implementation and may not be as strong as the original RC4 implementation. No attempt is made to look for modern OS-provided CSPRNGs like arc4random() that is widely available. This issue has been fixed in version 1.19.1.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.009 (58.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 58.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: -0.000
Affected products
- C-Ares — versions < 1.19.1
- C-Ares Project
- Fedoraproject Fedora — versions 37, 38
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/c-ares/c-ares/security/advisories/GHSA-8r8p-23f3-64c2 (Third Party Advisory)
- github.com/c-ares/c-ares/releases/tag/cares-1_19_1 (Release Notes)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (Mailing List, Third Party Advisory)
- security.gentoo.org/glsa/202310-09 (Third Party Advisory)
Frequently asked questions
- What is CVE-2023-31147?
- CVE-2023-31147 is a medium-severity vulnerability in C-Ares, classified under Use of Insufficiently Random Values. CVSS score: 5.9/10. Published 2023-05-25.
- How severe is CVE-2023-31147?
- Medium severity. CVSS v3 base score is 5.9 out of 10.
- Is CVE-2023-31147 known to be exploited?
- 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.