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Big Ip Access Policy ManagerApplication · F5

CVE-2002-20001

HIGH · 7.5 CVSS v3.1 Published 2021-11-11
Fix available
A fix is available. Upgrade to 16.1.4 / 17.1.0 or later.
See remediation →
84/100
Remediation priority · High
Public exploit 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
The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary numbers that are actually not public keys, and trigger expensive server-side DHE modular-exponentiation calculations, aka a D(HE)at or D(HE)ater attack. The client needs very little CPU resources and network bandwidth. The attack may be more disruptive in cases where a client can require a server to select its largest supported key size. The basic attack scenario is that the client must claim that it can only communicate with DHE, and the server must be configured to allow DHE.

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
How this class of weakness works · CWE-400

A single request can consume unbounded CPU, memory, or connections, so a modest amount of malicious traffic exhausts the service. The result is denial of service for everyone else. Remediation is enforcing limits, quotas, and timeouts on what any one request can use.

General guidance for the uncontrolled resource consumption class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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:>= 13.1.0, < 16.1.4>= 17.0.0, < 17.1.0
Big Ip Advanced Firewall ManagerApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0
Big Ip Advanced Web Application FirewallApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0
Big Ip AnalyticsApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0
Big Ip Application Acceleration ManagerApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0
Big Ip Application Security ManagerApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0
Big Ip Application Visibility And ReportingApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0
Big Ip Carrier Grade NatApplication
Affected:>= 13.1.0, <= 17.1.2= 17.5.0

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

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 16.1.4 / 17.1.0 or later
Fixed in 16.1.417.1.0
Recommended fix Moderate confidence

Upgrade to BIG-IP 16.1.4 or later for APM installations on 13.1.x-16.1.x branches; upgrade to BIG-IP 17.1.0 or later for APM on 17.0.x; for all other affected modules, upgrade to a stable release beyond 17.1.2 (such as 17.1.3 or the latest stable 17.x release).

  1. 1. Identify the specific BIG-IP module(s) affected in your environment by checking the installed version of each BIG-IP component.
  2. 2. Access the BIG-IP configuration utility or use 'tmsh show sys version' to confirm current versions of all affected modules.
  3. 3. For BIG-IP Access Policy Manager (APM) deployments: If running >= 13.1.0 and < 16.1.4, plan upgrade to version 16.1.4 or later. If running >= 17.0.0 and < 17.1.0, upgrade to version 17.1.0 or later.
  4. 4. For BIG-IP Advanced Firewall Manager (AFM), Advanced Web Application Firewall (AWAF), Analytics, Application Acceleration Manager, Application Security Manager, Application Visibility and Reporting, and Carrier Grade NAT: Upgrade to a version beyond 17.1.2 (such as 17.1.3 or later stable release). Note that version 17.5.0 is also affected, so avoid that specific version.
  5. 5. Prior to upgrade, back up the BIG-IP configuration using 'tmsh save sys config' or the configuration utility.
  6. 6. Schedule maintenance window as DHE cipher changes may cause temporary service interruption.
  7. 7. Perform the upgrade following F5 upgrade procedures, verifying integrity after completion.
  8. 8. After upgrade, verify the fix is applied by confirming DHE cipher handling or reviewing K512723: f5.com/support/answers/000051268
Caveat Upgrading BIG-IP major versions may introduce changes to feature behavior, deprecated modules, or configuration syntax; review F5 release notes for breaking changes between current and target versions before proceeding.

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

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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-2002-20001 in production — separate from our analysis above.

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