CVE-2008-5540
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 · uneditedSecure Computing Secure Web Gateway (aka Webwasher), when Internet Explorer 6 or 7 is used, allows remote attackers to bypass detection of malware in an HTML document by placing an MZ header (aka "EXE info") at the beginning, and modifying the filename to have (1) no extension, (2) a .txt extension, or (3) a .jpg extension, as demonstrated by a document containing a CVE-2006-5745 exploit.
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 confidenceSecure Computing Secure Web Gateway (Webwasher) fails to detect malware in HTML documents when an MZ header (EXE executable marker) is prepended to the HTML content and the file is given a non-executable extension (.txt, .jpg, or no extension). This allows attackers to bypass the gateway's malware detection and deliver exploits like CVE-2006-5745 to vulnerable clients.
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 dataall versionsall versionsCVSS 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
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:M/Au:N/C:C/I:C/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 checksWork through these to decide whether this CVE applies to you.
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Confirm presence of Secure Web Gateway or WebwasherReview installed software on gateway/proxy servers, or check network topology for Secure Computing security appliances. Look for processes named 'webwasher' or 'swg' running on the system.Affected if Secure Computing Secure Web Gateway or Webwasher is deployed on the network as a security gateway.
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Verify web filtering or malware scanning is activeCheck the product configuration via admin console or CLI. Look for enabled policies that scan HTTP/HTTPS traffic for malware in web content.Affected if The web filtering module is enabled and processing traffic - the bypass only matters if the product is actively scanning web content.
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Confirm all versions are vulnerableSince vendor stated 'all versions' are affected, no specific version number needs to be matched - any installation of the product falls within the affected range.Affected if Any version of Secure Web Gateway or Webwasher is installed and operational.
If Secure Computing Secure Web Gateway or Webwasher is deployed and actively scanning web traffic, the environment is affected by this detection bypass vulnerability.
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 to a patched version of Secure Web Gateway if available, or implement additional content inspection at other security layers (email gateway, endpoint protection) to detect HTML files with embedded executable headers.
- 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-2008-5540 — 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-2008-5540 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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- 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
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