Secure Firewall Threat DefenseApplication · Cisco
CVE-2024-20363
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 · uneditedMultiple Cisco products are affected by a vulnerability in the Snort Intrusion Prevention System (IPS) rule engine that could allow an unauthenticated, remote attacker to bypass the configured rules on an affected system. This vulnerability is due to incorrect HTTP packet handling. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass configured IPS rules and allow uninspected traffic onto the network.
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 confidenceThis is a Snort IPS rule bypass vulnerability affecting multiple Cisco products where incorrect HTTP packet handling allows crafted HTTP packets to circumvent configured intrusion prevention rules, permitting uninspected traffic onto the network.
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
Secure Firewall Threat DefenseApplication
= 7.4.0
Unified Threat Defense Snort Intrusion Prevention System EngineOperating system
= 17.6.4= 17.6.5= 17.12.1a= 17.12.2
SnortApplication
>= 3.0.0-233, < 3.1.69.0CVSS 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
- Changed
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 checksWork through these to decide whether this CVE applies to you.
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Identify your Cisco security productDetermine whether your environment uses Cisco Firepower Threat Defense, Cisco Unified Threat Defense, or standalone Cisco Snort. Check the product model and name from the device console or management interface.Affected if The product is any of: Cisco Firepower Threat Defense, Cisco Unified Threat Defense with Snort IPS, or standalone Cisco Snort IPS.
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Check Firepower Threat Defense versionRun 'show version' or access the FTD management interface to retrieve the installed FTD version number.Affected if The installed version is exactly 7.4.0.
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Check Unified Threat Defense Snort IPS versionAccess the UTD container or check the Snort IPS engine version via 'show snort version' or the device management console.Affected if The installed Snort IPS version is exactly 17.6.4, 17.6.5, 17.12.1a, or 17.12.2.
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Check standalone Snort versionRun 'snort --version' or check the Snort package version installed on the system.Affected if The installed Snort version is 3.0.0-233 or higher, but lower than 3.1.69.0.
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Confirm Snort IPS is enabled and processing HTTP trafficCheck the active Snort policy configuration via 'show snort inspection' or through the management interface. Verify that HTTP/HTTPS inspection is enabled as part of the intrusion prevention policy.Affected if Snort IPS is active and HTTP traffic inspection is configured, and the version falls within any affected range above.
You are affected if your product runs Firepower Threat Defense 7.4.0, Unified Threat Defense Snort IPS 17.6.4/17.6.5/17.12.1a/17.12.2, or standalone Snort between version 3.0.0-233 and 3.1.69.0, and you have HTTP inspection enabled in your IPS policy.
Generated from the published advisory. Verify against your own configuration.
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 data3.1.69.0
Apply Cisco-provided Snort rule updates and product firmware patches to correct the HTTP packet handling logic in the IPS engine.
Fix this in Secure Firewall Threat Defense
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-20363 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-20363 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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