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Big Ip Local Traffic ManagerApplication · F5

CVE-2018-5743

HIGH · 7.5 CVSS v3.1 Published 2019-10-09
Fix available
A fix is available. Upgrade to after 14.1.1 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
By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.

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

BIND DNS server contains a flaw in its TCP connection limiting mechanism where the code intended to enforce a maximum number of simultaneous TCP connections fails to properly restrict connections, allowing attackers to exceed the configured limit and exhaust server resources leading to denial of service.

MitigationUpdate BIND to version 9.11.7, 9.12.5, 9.14.1, or later which contain the fix for this connection limit bypass vulnerability.

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:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.0.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.0.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.1.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0
Big Ip AnalyticsApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.0.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0
Big Ip Access Policy ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.1.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0
Big Ip Application Security ManagerApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.0.0, <= 13.1.1>= 14.0.0, <= 14.1.1= 15.0.0
Big Ip Edge GatewayWeb browser
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.0.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0
Big Ip Fraud Protection ServiceApplication
Affected:>= 11.5.2, <= 11.6.5>= 12.1.0, <= 12.1.4>= 13.0.0, <= 13.1.1>= 14.0.0, <= 14.1.0= 15.0.0

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
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 F5 Big-IP product version
    Run 'tmsh show sys version' or log into the web UI and navigate to System > Software Management > ISO Image to view the installed version
    Affected if The displayed version falls within any of these ranges: 11.5.2-11.6.5, 12.1.0-12.1.4, 13.0.0-13.1.1, 14.0.0-14.1.0 (or 14.1.1 for ASM), or equals 15.0.0
  2. Identify which Big-IP modules are deployed
    Run 'tmsh list sys provision' to list all provisioned modules on the device
    Affected if Any provisioned module (LTM, APM, AFM, Analytics, ASM, Edge Gateway, or FPS) is present on an affected version
  3. Confirm BIND DNS service is enabled
    Run 'tmsh list sys service dns' or check if DNS profile is configured under Local Traffic > Profiles > Services > DNS
    Affected if DNS service or DNS profiles are actively configured on the Big-IP device

You are affected if your F5 Big-IP device runs any of the listed modules on versions 11.5.2 through 11.6.5, 12.1.0 through 12.1.4, 13.0.0 through 13.1.1, 14.0.0 through 14.1.0/14.1.1, or exactly version 15.0.0, and the BIND DNS service is enabled.

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 14.1.1
Interim mitigation

Update BIND to version 9.11.7, 9.12.5, 9.14.1, or later which contain the fix for this connection limit bypass vulnerability.

Fix this in Big Ip Local Traffic Manager Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,648.

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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-2018-5743 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