CyberSecBulletin
CVE-2023-25565NVD status: Modified

gss-ntlmssp: Release of Invalid Pointer or Reference

Published Updated By the CyberSecBulletin desk

CVE-2023-25565 is a high-severity release of invalid pointer or reference vulnerability in gss-ntlmssp from Gssapi, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected gss-ntlmssp versions: < 1.2.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.1% chance of exploitation within 30 days, higher than 66% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of gss-ntlmssp you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Gssapigss-ntlmssp< 1.2.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighCNA (github.com)
CVSS 3.17.5HighNVD

Official description

GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, an incorrect free when decoding target information can trigger a denial of service. The error condition incorrectly assumes the `cb` and `sh` buffers contain a copy of the data that needs to be freed. However, that is not the case. This vulnerability can be triggered via the main `gss_accept_sec_context` entry point. This will likely trigger an assertion failure in `free`, causing a denial-of-service. This issue is fixed in version 1.2.0.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Release of Invalid Pointer or Reference

The product attempts to return a memory resource to the system, but it calls the wrong release function or calls the appropriate release function incorrectly.

How developers prevent this class of flaw

  • Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free().
  • When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, glibc in Linux provides protection against free of invalid pointers.

More Release of Invalid Pointer or Reference vulnerabilities (CWE-763)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in gss-ntlmssp

All gss-ntlmssp vulnerabilities

Recent Release of Invalid Pointer or Reference vulnerabilities

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