CVE-2009-1211
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 · uneditedBlue Coat ProxySG, when transparent interception mode is enabled, uses the HTTP Host header to determine the remote endpoint, which allows remote attackers to bypass access controls for Flash, Java, Silverlight, and probably other technologies, and possibly communicate with restricted intranet sites, via a crafted web page that causes a client to send HTTP requests with a modified Host header.
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 confidenceBlue Coat ProxySG in transparent interception mode improperly uses the HTTP Host header to determine the destination endpoint, allowing attackers to bypass security controls by manipulating the Host header in requests. This enables Flash, Java, Silverlight, and other client-side technologies to bypass access restrictions and communicate with restricted intranet sites through the proxy.
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 versionsall versionsall versionsall versionsall versionsall 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
- None
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:N/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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Confirm Blue Coat ProxySG is deployedIdentify any Blue Coat ProxySG appliance (physical or virtual) in the environment. Check system inventory, network diagrams, or running services for 'ProxySG', 'SG210', or 'Blue Coat' references.Affected if Blue Coat ProxySG of any version listed in the affected products is present in the environment
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Verify transparent interception mode is enabledAccess the ProxySG management console or CLI and inspect the interception mode settings. In the CLI, use 'show intercept' or view the transparent proxy configuration. In the GUI, check 'Configuration > Transparent Proxy Settings'.Affected if Transparent interception mode is enabled and active on the proxy
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Check Host header reliance for destination resolutionReview the proxy policy layers and rules that handle request routing. Look for policies that use the Host header field as the sole or primary factor for determining the destination server. In the management console, examine 'Policy > Visual Policy Manager' or 'Policy > CPL' for rules referencing 'http.host' or 'header.xfer.ip' without additional validation.Affected if The proxy uses the Host header as the primary or only method to determine the destination endpoint without additional validation such as DNS resolution verification or destination IP confirmation
If Blue Coat ProxySG is deployed with transparent interception mode enabled and the proxy relies on the HTTP Host header alone to determine destination endpoints, the environment is affected by this 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 dataDisable transparent interception mode or implement additional validation beyond the Host header (e.g., validate against DNS resolution, use explicit proxy configuration, or implement stricter policy controls) to ensure proper endpoint determination and access control enforcement.
- Consultation6.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2009-1211 — 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-2009-1211 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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