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Big Ip Local Traffic ManagerApplication · F5

CVE-2018-5532

MEDIUM · 5.3 CVSS v3.0 Published 2018-07-19
Fix available
A fix is available. Upgrade to after 12.1.2 or later.
See remediation →
62/100
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
On F5 BIG-IP 13.0.0, 12.1.0-12.1.2, 11.6.0-11.6.3.1, or 11.2.1-11.5.6 a domain name cached within the DNS Cache of TMM may continue to be resolved by the cache even after the parent server revokes the record, if the DNS Cache is receiving a stream of requests for the cached name.

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

F5 BIG-IP TMM DNS cache continues serving stale domain name resolutions even after the authoritative server revokes the record, when the DNS cache receives a continuous stream of requests for that cached name. This allows attackers to potentially reach IP addresses that should no longer be valid.

MitigationApply the appropriate F5 hotfix or upgrade to a fixed version as specified in the F5 security advisory.

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 Local Traffic ManagerApplication
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip AnalyticsApplication
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Access Policy ManagerApplication
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Application Security ManagerApplication
Affected:>= 10.1.0, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Domain Name SystemApplication
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0
Big Ip Edge GatewayWeb browser
Affected:>= 11.2.1, <= 11.5.6>= 11.6.0, <= 11.6.3.1>= 12.1.0, <= 12.1.2= 13.0.0

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
Low
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 F5 BIG-IP product version
    Run 'tmsh show /sys version' or check /etc/product_version to obtain the installed version
    Affected if The version falls within >= 11.2.1 <= 11.5.6, >= 11.6.0 <= 11.6.3.1, >= 12.1.0 <= 12.1.2, or = 13.0.0
  2. Confirm DNS cache module is active
    Run 'tmsh show /ltm dns' or 'tmsh list /ltm dns cache' to check if DNS caching is enabled on the TMM
    Affected if DNS cache is enabled and serving responses
  3. Check DNS cache statistics for stale responses
    Run 'tmsh show /ltm dns cache statistics' and review cache age/ttl values compared to configured cache settings
    Affected if Cached entries are being served beyond their intended TTL under high request load
  4. Identify which BIG-IP module uses DNS caching
    Review installed modules via 'tmsh show /sys module' and check which modules (LTM, AAM, AFM, DNS, ASM, APM, Analytics, Edge Gateway) have DNS proxy/cache enabled
    Affected if Any of the affected modules (LTM, AAM, AFM, Analytics, APM, ASM, DNS, Edge Gateway) are running with DNS cache enabled

You are affected if you run any of the listed BIG-IP modules on a version within the affected ranges AND have DNS cache enabled in your configuration.

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 12.1.2
Interim mitigation

Apply the appropriate F5 hotfix or upgrade to a fixed version as specified in the F5 security advisory.

Fix this in Big Ip Local Traffic Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.

Scan for this in your stack

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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-2018-5532 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