Cyber Resilience

CVE-2023-31147

Crypto Weakness in Fedoraproject Fedora 37 … 38

Crypto Weakness
Published
25 May 2023
Modified
21 November 2024
CVSS Score v3.1 5.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0091 57th percentile
Risk Priority 48 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-31147 is a medium-severity Use of Insufficiently Random Values (CWE-330) vulnerability in Fedoraproject Fedora. Its CVSS base score is 5.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Forge Web Credentials (T1606); ranked in the top 43% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-330

Related Threats

MITRE ATT&CK Enterprise Techniques

T1606 Forge Web Credentials Credential Access
Adversaries may forge credential materials that can be used to gain access to web applications or Internet services.
attack.mitre.org →
T1606.001 Web Cookies Credential Access
Adversaries may forge web cookies that can be used to gain access to web applications or Internet services.
attack.mitre.org →
T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1558 Steal or Forge Kerberos Tickets Credential Access
Adversaries may attempt to subvert Kerberos authentication by stealing or forging Kerberos tickets to enable [Pass the Ticket](https://attack.
attack.mitre.org →
T1563 Remote Service Session Hijacking Lateral Movement
Adversaries may take control of preexisting sessions with remote services to move laterally in an environment.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-31124Same product: C-Ares Project C-Ares
CVE-2023-32067Same product: C-Ares Project C-Ares
CVE-2023-31130Same product: C-Ares Project C-Ares
CVE-2023-34353Shared CWE-330
CVE-2024-35292Shared CWE-330
CVE-2024-21460Shared CWE-330
CVE-2025-15574Shared CWE-330
CVE-2025-11707Shared CWE-330
CVE-2023-46740Shared CWE-330
CVE-2023-0343Shared CWE-330

Affected Assets

c-ares project
c-ares
≤ 1.19.1
fedoraproject
fedora
37, 38

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

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Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 8 hardening rules · 4 OS baselines
Validate
Prove the fix (OWASP ASVS)

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Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-12 Cryptographic Key Establishment and Management
addresses: CWE-330

Key generation under controlled management uses approved random-bit sources rather than insufficiently random values.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly enforce use of cryptographically strong RNGs and catch insufficient randomness during design, coding, and testing.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.24 Use of cryptography mostly match
prevents

Cryptographic controls require use of approved, sufficiently random values for keys and nonces.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect weak randomness but does not prescribe the control itself.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC processes include verification steps that can catch insufficient randomness but do not directly specify RNG requirements.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly prohibit use of weak or predictable random number generators.

A.8.5 Secure authentication partial match
degrades

Secure authentication mechanisms depend on unpredictable values (nonces, salts, session tokens) to resist guessing.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248563 The OL 8 SSH server must be configured to use strong entropy. prevents CWE-330
  • V-248599 OL 8 must enable the hardware random number generator entropy gatherer service. prevents CWE-330
  • V-248600 OL 8 must have the packages required to use the hardware random number generator entropy gatherer service. prevents CWE-330
Oracle Linux 9 (1 rule)
  • V-271511 OL 9 must enable the hardware random number generator entropy gatherer service. prevents CWE-330
RHEL 8 (3 rules)
  • V-244527 RHEL 8 must have the packages required to use the hardware random number generator entropy gatherer service. prevents CWE-330
  • V-230253 RHEL 8 must ensure the SSH server uses strong entropy. prevents CWE-330
  • V-230285 RHEL 8 must enable the hardware random number generator entropy gatherer service. prevents CWE-330
RHEL 9 (1 rule)
  • V-257782 RHEL 9 must enable the hardware random number generator entropy gatherer service. prevents CWE-330

References