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Firewall Services Module SoftwarePlugin / extension · Cisco

CVE-2011-3297

HIGH · 7.8 CVSS v2.0 Published 2011-10-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
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
Cisco Firewall Services Module (aka FWSM) 3.1 before 3.1(21), 3.2 before 3.2(22), 4.0 before 4.0(16), and 4.1 before 4.1(7), when certain authentication configurations are used, allows remote attackers to cause a denial of service (module crash) by making many authentication requests for network access, aka Bug ID CSCtn15697.

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

A denial of service vulnerability in Cisco Firewall Services Module (FWSM) allows remote attackers to crash the module by sending numerous authentication requests when certain authentication configurations are enabled. The vulnerability affects multiple version branches (3.1, 3.2, 4.0, 4.1) prior to their respective patched releases.

MitigationApply the vendor-supplied software updates (3.1(21), 3.2(22), 4.0(16), or 4.1(7) and later) to resolve the vulnerability. Until patched, consider implementing rate-limiting on authentication requests or reviewing authentication configuration settings to reduce exposure.

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
Firewall Services Module SoftwarePlugin / extension
Affected:= 3.1= 3.1\(2\)= 3.1\(3\)= 3.1\(4\)= 3.1\(5\)= 3.1\(6\)= 3.1\(7\)= 3.1\(8\)= 3.1\(9\)= 3.1\(10\)= 3.1\(11\)= 3.1\(12\)
Catalyst 6500Hardware / appliance
Affected:all versions
Catalyst 7600Hardware / appliance
Affected:all versions

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
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete

AV:N/AC:L/Au:N/C:N/I:N/A:C

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 FWSM software version
    Connect to the Cisco Catalyst 6500/7600 chassis and execute 'show module' or 'show version' commands to display the Firewall Services Module version information. Look for the FWSM software version in the output.
    Affected if The FWSM runs a version prior to 3.1(21), 3.2(22), 4.0(16), or 4.1(7) - specifically any 3.1.x through 3.1(12), 3.2.x prior to 3.2(22), 4.0.x prior to 4.0(16), or 4.1.x prior to 4.1(7)
  2. Verify authentication is enabled on FWSM
    Execute 'show running-config | include authentication' or 'show aaa' commands on the FWSM to determine if any authentication configuration is active. The vulnerability triggers when certain authentication configurations are enabled.
    Affected if Authentication is configured and enabled on the FWSM (such as TACACS+, RADIUS, or local authentication for device access or network connections)
  3. Confirm platform is Catalyst 6500 or 7600
    Identify the host platform by executing 'show version' on the chassis. The FWSM runs exclusively on Cisco Catalyst 6500 series switches and Cisco Catalyst 7600 series routers.
    Affected if The FWSM is installed in a Cisco Catalyst 6500 or 7600 chassis (all versions of these platforms are affected when running vulnerable FWSM code)

You are affected if your FWSM runs a version prior to the patched releases AND authentication is enabled on the module, as the DoS condition requires both the vulnerable code version and active authentication configuration to be present.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-supplied software updates (3.1(21), 3.2(22), 4.0(16), or 4.1(7) and later) to resolve the vulnerability. Until patched, consider implementing rate-limiting on authentication requests or reviewing authentication configuration settings to reduce exposure.

Fix this in Firewall Services Module Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,330
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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-2011-3297 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
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