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Big Ip Access Policy ManagerApplication · F5

CVE-2021-23045

HIGH · 7.5 CVSS v3.1 Published 2021-09-14
Fix available
A fix is available. Upgrade to 13.1.4.1 / 14.1.4.3 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
On BIG-IP version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.3, 13.1.x before 13.1.4.1, and all versions of 12.1.x, when an SCTP profile with multiple paths is configured on a virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A denial of service vulnerability exists in F5 BIG-IP where specially crafted SCTP traffic targeting a virtual server configured with an SCTP profile using multiple paths can cause the Traffic Management Microkernel (TMM) to terminate. The attack requires network access to the virtual server and does not require authentication.

MitigationUpgrade BIG-IP to versions 16.0.1.2+, 15.1.3.1+, 14.1.4.3+, or 13.1.4.1+ (12.1.x has no fix). If upgrading is not feasible, consider removing SCTP profiles with multiple paths from virtual servers or blocking SCTP traffic at the network perimeter.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Big Ip Access Policy ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Advanced Firewall ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Advanced Web Application FirewallApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip AnalyticsApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Application Acceleration ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Application Security ManagerApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Ddos Hybrid DefenderApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2
Big Ip Domain Name SystemApplication
Affected:>= 12.1.0, <= 12.1.6>= 13.1.0, < 13.1.4.1>= 14.1.0, < 14.1.4.3>= 15.1.0, < 15.1.3.1>= 16.0.0, < 16.0.1.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check BIG-IP version
    Run 'tmsh show sys version' or view the version in the web UI under System > Software Management > ISO Image
    Affected if Version is 12.1.0-12.1.6, 13.1.0-13.1.4, 14.1.0-14.1.4.2, 15.1.0-15.1.3.0, or 16.0.0-16.0.1.1
  2. Identify SCTP profiles
    Run 'tmsh list ltm profile sctp all' to list all SCTP profiles on the device
    Affected if Any SCTP profiles exist on the system
  3. Check SCTP profile for multipath configuration
    Run 'tmsh list ltm profile sctp <profile_name>' and look for 'multipath enabled' set to 'yes'
    Affected if An SCTP profile has multipath enabled
  4. Identify virtual servers using SCTP profiles
    Run 'tmsh list ltm virtual all' and search for 'sctp' in the output to find virtual servers with SCTP profiles assigned
    Affected if A virtual server references an SCTP profile

You are affected if your BIG-IP version is within the listed vulnerable ranges AND you have a virtual server using an SCTP profile with multipath enabled exposed to network traffic.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 13.1.4.1 / 14.1.4.3 / 15.1.3.1 or later
Fixed in 13.1.4.114.1.4.315.1.3.1
Interim mitigation

Upgrade BIG-IP to versions 16.0.1.2+, 15.1.3.1+, 14.1.4.3+, or 13.1.4.1+ (12.1.x has no fix). If upgrading is not feasible, consider removing SCTP profiles with multiple paths from virtual servers or blocking SCTP traffic at the network perimeter.

Recommended fix High confidence

Upgrade to BIG-IP 16.0.1.2 or later, or 15.1.3.1 or later, or 14.1.4.3 or later, or 13.1.4.1 or later based on your current major version branch. Note: 12.1.x has no fix available as it is End of Technical Support.

  1. 1. Identify all BIG-IP devices running affected versions (12.1.x, 13.1.x < 13.1.4.1, 14.1.x < 14.1.4.3, 15.1.x < 15.1.3.1)
  2. 2. Identify virtual servers configured with SCTP profiles that have multiple paths enabled
  3. 3. Schedule a maintenance window for the upgrade
  4. 4. Download the appropriate hotfix from F5 Networks support portal (support.f5.com)
  5. 5. Upload and install the hotfix on each affected BIG-IP device: tmsh install sys software hotfix <volume> <hotfix-file>
  6. 6. Verify the upgrade was successful: tmsh show sys software status
  7. 7. Confirm the TMM process is running normally: tmsh show sys tmm-info
  8. 8. Test that virtual servers with SCTP profiles are functioning properly
Caveat Review F5 release notes for any known compatibility issues between your current version and target fixed version before upgrading. Note that 12.1.x reached End of Technical Support with no patch available - migration to a supported version is required.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-23045 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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