CVE-2023-31147 Insufficient randomness in generation of DNS query IDs in c-ares

2023-05-2521:55:47

CWE-330

GitHub_M

www.cve.org

c-ares

weak randomness

dns query

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

7.2 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

40.3%

JSON

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.

CNA Affected

[
  {
    "vendor": "c-ares",
    "product": "c-ares",
    "versions": [
      {
        "version": "< 1.19.1",
        "status": "affected"
      }
    ]
  }
]