CyberSecBulletin
CVE-2022-41836NVD status: Modified

When an 'Attack Signature False Positive Mode' enabled security policy is configured on a…

Published Updated By the CyberSecBulletin desk

CVE-2022-41836 is a high-severity improper input validation vulnerability in BIG-IP Advanced WAF & ASM 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, 15.1.7 as the first without the flaw, so updating BIG-IP Advanced WAF & ASM 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 Advanced WAF & ASM to 17.0.0.1 or 16.1.3.1 or 15.1.7, whichever matches your release line, or a later version.
  2. Update Big-ip Advanced Web Application Firewall to 15.1.7 or 16.1.3.1, whichever matches your release line, or a later version.
  3. Update Big-ip Application Security Manager to 15.1.7 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 Advanced WAF & ASM17.0.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, 15.1.717.0.0.1, 16.1.3.1, 15.1.7
F5Big-ip Advanced Web Application Firewall15.1.0 up to, but not including, 15.1.7; 16.1.0 up to, but not including, 16.1.3.1; 17.0.015.1.7, 16.1.3.1
F5Big-ip Application Security Manager15.1.0 up to, but not including, 15.1.7; 16.1.0 up to, but not including, 16.1.3.1; 17.0.015.1.7, 16.1.3.1

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

When an 'Attack Signature False Positive Mode' enabled security policy is configured on a virtual server, undisclosed requests can cause the bd process to terminate.

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

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

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 BIG-IP Advanced WAF & ASM

All BIG-IP Advanced WAF & ASM vulnerabilities

Recent Improper Input Validation vulnerabilities

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