dbcve.org
Big Ip Application Security ManagerApplication · F5

CVE-2018-5539

HIGH · 7.5 CVSS v3.0 Published 2018-07-25
Fix available
A fix is available. Upgrade to after 13.1.0 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
Under certain conditions, on F5 BIG-IP ASM 13.0.0-13.1.0.7, 12.1.0-12.1.3.5, 11.6.0-11.6.3.1, 11.5.1-11.5.6, or 11.2.1, when processing CSRF protections, the BIG-IP ASM bd process may restart and produce a core file.

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

F5 BIG-IP ASM contains a denial-of-service vulnerability in the bd process triggered during CSRF protection handling. Under specific conditions related to CSRF token validation or session processing, the ASM bd process can unexpectedly restart and generate a core file, potentially disrupting application security services.

MitigationUpdate F5 BIG-IP ASM to a version beyond the affected releases (13.1.0.8+, 12.1.3.6+, 11.6.3.2+, 11.5.7+, 11.2.1.1+) or apply available hotfixes. Consider disabling CSRF protection temporarily if immediate patching is not feasible, though this reduces security.

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 Application Security ManagerApplication
Affected:>= 11.5.1, <= 11.5.6>= 11.6.1, <= 11.6.3>= 12.1.0, <= 12.1.3>= 13.0.0, <= 13.1.0= 11.2.1

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:3.0/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. Confirm BIG-IP ASM module is installed and running
    Log into the BIG-IP Configuration Utility (TMSH) and run: tmsh show sys module | grep asm. Alternatively, check if the bd process exists: tmsh show process bd
    Affected if ASM module is not installed or the bd process does not exist, the vulnerability does not apply
  2. Check installed BIG-IP version against affected ranges
    Run: tmsh show sys version. Compare the displayed version to the affected ranges: 11.2.1, 11.5.1-11.5.6, 11.6.1-11.6.3, 12.1.0-12.1.3, 13.0.0-13.1.0
    Affected if The installed version falls within any of these affected ranges and ASM is enabled, the system is potentially vulnerable
  3. Determine if CSRF protection is enabled in ASM policies
    In the BIG-IP Configuration Utility, navigate to: Security > Application Security > Policies. For each ASM policy, check the CSRF protection settings under the policy's Security > CSRF Protection section. Alternatively, use TMSH: tmsh list asm policy <policy_name> csrf-protection
    Affected if CSRF protection is enabled in any ASM policy, the vulnerable code path can be triggered
  4. Search for bd process restarts or crashes in system logs
    Run: tmsh show sys log daemon.log | grep -i 'bd.*restart' or search for core files: tmsh show sys core. Also check /var/core/ directory for recent core files related to the bd process
    Affected if The bd process has been unexpectedly restarting or core files exist, this indicates the vulnerability has been triggered
  5. Check for application security service disruptions
    Review ASM event logs for sudden policy reloads or service interruptions: tmsh show asm status. Look for entries indicating the Application Security Manager service became unavailable
    Affected if ASM security services have been disrupted with no other explanation, this may indicate the DoS condition from this CVE

A system is affected if it runs a BIG-IP version within the specified ranges, has ASM module enabled with CSRF protection configured, and exhibits bd process instability or crashes.

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 a release after 13.1.0
Interim mitigation

Update F5 BIG-IP ASM to a version beyond the affected releases (13.1.0.8+, 12.1.3.6+, 11.6.3.2+, 11.5.7+, 11.2.1.1+) or apply available hotfixes. Consider disabling CSRF protection temporarily if immediate patching is not feasible, though this reduces security.

Fix this in Big Ip Application Security Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

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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-2018-5539 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data