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Big Ip Access Policy ManagerApplication · F5

CVE-2020-5917

MEDIUM · 5.9 CVSS v3.1 Published 2020-08-26
Fix available
A fix is available. Upgrade to 12.1.5.2 / 14.1.2.4 or later.
See remediation →
68/100
Remediation priority · Elevated
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
In BIG-IP versions 15.1.0-15.1.0.4, 15.0.0-15.0.1.3, 14.1.0-14.1.2.3, 13.1.0-13.1.3.4, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.2 and BIG-IQ versions 5.2.0-7.0.0, the host OpenSSH servers utilize keys of less than 2048 bits which are no longer considered secure.

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 · high confidence

The BIG-IP and BIG-IQ host OpenSSH servers use SSH host keys smaller than 2048 bits, which are considered cryptographically insecure by modern standards. Keys of insufficient length are vulnerable to cryptanalytic attacks, potentially allowing an attacker to recover the private key and impersonate the server.

MitigationRegenerate SSH host keys on all affected devices using RSA keys of at least 2048 bits (preferably 4096 bits) or stronger algorithms like Ed25519, then ensure the new host keys are properly distributed to prevent man-in-the-middle attacks.

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:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip AnalyticsApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip Application Security ManagerApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip Domain Name SystemApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip Fraud Protection ServiceApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5
Big Ip Global Traffic ManagerApplication
Affected:>= 11.6.1, <= 11.6.5>= 12.1.0, < 12.1.5.2>= 13.1.0, <= 13.1.3>= 14.1.0, < 14.1.2.4>= 15.0.0, < 15.0.1.4>= 15.1.0, < 15.1.0.5

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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. Identify the BIG-IP version
    Run 'tmsh show sys version' or 'bigtop_versions' to determine the installed version and module (such as APM, AFM, Analytics, AAM, ASM, DNS, FPS, GTM)
    Affected if The version falls within any of these ranges: 11.6.1 to 11.6.5; 12.1.0 to 12.1.5.1; 13.1.0 to 13.1.3; 14.1.0 to 14.1.2.3; 15.0.0 to 15.1.0.3; or 15.1.0 to 15.1.0.4
  2. Locate SSH host key files
    On the BIG-IP system, list the SSH host key files typically found in /etc/ssh/ using 'ls -la /etc/ssh/ssh_host_*'
    Affected if Host key files exist in the standard SSH directory
  3. Check RSA host key bit length
    Run 'ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key' to display the bit length of the RSA host key
    Affected if The reported key length is less than 2048 bits (common weak sizes are 1024 or 2048 bits)
  4. Check ECDSA host key bit length
    Run 'ssh-keygen -l -f /etc/ssh/ssh_host_ecdsa_key' to display the bit length of the ECDSA host key
    Affected if The reported key length is less than 256 bits (ECDSA curves below P-256 are considered weak)
  5. Check DSA host key bit length
    Run 'ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key' to check if a DSA key exists and its bit length
    Affected if A DSA host key is present (DSA keys are limited to 1024 bits by OpenSSH and are insecure)

You are affected if your BIG-IP version is within the listed vulnerable ranges AND any SSH host key on the system is smaller than 2048 bits (RSA) or uses weak algorithms like DSA.

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.

From vendor data
Upgrade available Upgrade to 12.1.5.2 / 14.1.2.4 / 15.0.1.4 or later
Fixed in 12.1.5.214.1.2.415.0.1.4
Interim mitigation

Regenerate SSH host keys on all affected devices using RSA keys of at least 2048 bits (preferably 4096 bits) or stronger algorithms like Ed25519, then ensure the new host keys are properly distributed to prevent man-in-the-middle attacks.

Fix this in Big Ip Access Policy Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

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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-2020-5917 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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