CVE-2024-7589

OpenSSH pre-authentication async signal safety issue

State
Published
Severity
8.1 High
Published
Aug 11, 2024
Updated
Aug 16, 2024
Reserved
Aug 7, 2024

Read the record on cve.org

Description

A signal handler in sshd(8) may call a logging function that is not async-signal-safe. The signal handler is invoked when a client does not authenticate within the LoginGraceTime seconds (120 by default). This signal handler executes in the context of the sshd(8)'s privileged code, which is not sandboxed and runs with full root privileges.

This issue is another instance of the problem in CVE-2024-6387 addressed by FreeBSD-SA-24:04.openssh. The faulty code in this case is from the integration of blacklistd in OpenSSH in FreeBSD.

As a result of calling functions that are not async-signal-safe in the privileged sshd(8) context, a race condition exists that a determined attacker may be able to exploit to allow an unauthenticated remote code execution as root.

Scores

CVSSScoreVectorSource
3.18.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HCISA-ADP

Weaknesses

  • CWE-364 Signal Handler Race Condition

Affected Products

ProductVersions
FreeBSDFreeBSD
  • 14.1-RELEASE to before p3Affected
  • 14.0-RELEASE to before p9Affected
  • 13.3-RELEASE to before p5Affected

References

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