CVE-2008-1804
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 · uneditedpreprocessors/spp_frag3.c in Sourcefire Snort before 2.8.1 does not properly identify packet fragments that have dissimilar TTL values, which allows remote attackers to bypass detection rules by using a different TTL for each fragment.
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 confidenceSnort's fragment reassembly preprocessor (spp_frag3.c) before version 2.8.1 fails to properly validate that IP packet fragments with different TTL (Time To Live) values belong to the same original packet. This allows attackers to craft fragmented packets with varying TTL values to evade detection rules that rely on fragment reassembly.
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<= 2.8.0CVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P
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 Snort installation and versionRun 'snort -V' or 'snort --version' to display the installed Snort versionAffected if The displayed version is 2.8.0 or lower
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Confirm the exact version numberCompare the version output against the affected range (Snort <= 2.8.0)Affected if The version number is 2.8.0 or any version lower than 2.8.0
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Locate the Snort configuration fileFind snort.conf (typically in /etc/snort/ or /usr/local/snort/etc/)Affected if A snort.conf file exists and the frag3 preprocessor is configured
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Verify the fragment preprocessor is enabledSearch the snort.conf for lines containing 'preprocessor frag3'Affected if The frag3 preprocessor is present and enabled in the configuration
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Check for rules that depend on fragment reassemblyReview loaded detection rules (in snort.conf or separate rules files) for any rules that could be evaded by manipulating fragment TTL valuesAffected if Any detection rules rely on fragment reassembly and could be bypassed using the TTL variation technique
You are affected if Snort version 2.8.0 or lower is installed and the frag3 preprocessor is enabled with rules that depend on proper fragment reassembly for detection.
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 dataUpgrade Snort to version 2.8.1 or later, which contains the fix for TTL validation in the fragment preprocessor.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2008-1804 — 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-2008-1804 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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