CyberSecBulletin
CVE-2022-41787NVD status: Modified

BIG-IP DNS: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2022-41787 is a high-severity NULL pointer dereference vulnerability in BIG-IP DNS from F5, 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. The record lists versions 17.0.0.1, 16.1.3.1, 15.1.6.1 as the first without the flaw, so updating BIG-IP DNS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.75% chance of exploitation within 30 days, higher than 55% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update BIG-IP DNS to 17.0.0.1 or 16.1.3.1 or 15.1.6.1 or 14.1.5.1, whichever matches your release line, or a later version.
  2. Update BIG-IP LTM to 17.0.0.1 or 16.1.3.1 or 15.1.6.1 or 14.1.5.1, whichever matches your release line, or a later version.
  3. Update Big-ip Domain Name System to 13.1.5.1 or 14.1.5.1 or 15.1.6.1 or 16.1.3.1, whichever matches your release line, or a later version.
  4. Read the advisory on support.f5.com for workarounds and exact fixed builds.
  5. 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
F5BIG-IP DNS17.0.x up to, but not including, 17.0.0.1; 16.1.x up to, but not including, 16.1.3.1; 15.1.x up to, but not including, 15.1.6.1; 14.1.x up to, but not including, 14.1.5.1; 13.1.x up to, but not including, 13.1.5.117.0.0.1, 16.1.3.1, 15.1.6.1, 14.1.5.1, 13.1.5.1
F5BIG-IP LTM17.0.x up to, but not including, 17.0.0.1; 16.1.x up to, but not including, 16.1.3.1; 15.1.x up to, but not including, 15.1.6.1; 14.1.x up to, but not including, 14.1.5.1; 13.1.x up to, but not including, 13.1.5.117.0.0.1, 16.1.3.1, 15.1.6.1, 14.1.5.1, 13.1.5.1
F5Big-ip Domain Name System13.1.0 up to, but not including, 13.1.5.1; 14.1.0 up to, but not including, 14.1.5.1; 15.1.0 up to, but not including, 15.1.6.1; 16.1.0 up to, but not including, 16.1.3.1; 17.0.0 up to, but not including, 17.0.0.113.1.5.1, 14.1.5.1, 15.1.6.1, 16.1.3.1, 17.0.0.1
F5Big-ip Local Traffic Manager13.1.0 up to, but not including, 13.1.5.1; 14.1.0 up to, but not including, 14.1.5.1; 15.1.0 up to, but not including, 15.1.6.1; 16.1.0 up to, but not including, 16.1.3.1; 17.0.0 up to, but not including, 17.0.0.113.1.5.1, 14.1.5.1, 15.1.6.1, 16.1.3.1, 17.0.0.1

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 (f5.com)
CVSS 3.17.5HighNVD

Official description

In BIG-IP versions 17.0.x before 17.0.0.1, 16.1.x before 16.1.3.1, 15.1.x before 15.1.6.1, 14.1.x before 14.1.5.1, and 13.1.x before 13.1.5.1, when DNS profile is configured on a virtual server with DNS Express enabled, undisclosed DNS queries with DNSSEC can cause TMM to terminate.

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

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

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

Recent NULL Pointer Dereference vulnerabilities

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