CVE-2005-1665
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 · uneditedThe __VIEWSTATE functionality in Microsoft ASP.NET 1.x, when not cryptographically signed, allows remote attackers to cause a denial of service (CPU consumption) via deeply nested markup.
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 confidenceIn ASP.NET 1.x, the __VIEWSTATE mechanism lacks built-in cryptographic integrity verification when MAC validation is disabled. Attackers can submit crafted viewstate containing deeply nested markup that triggers exponential parsing complexity, causing CPU exhaustion on the server.
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= 1.0= 1.1CVSS 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
- Partial
AV:N/AC:L/Au:N/C:N/I:N/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 installed ASP.NET versionCheck the version of ASP.NET installed on the system. Look for Microsoft .NET Framework version 1.0 or 1.1, typically found in C:\WINDOWS\Microsoft.NET\Framework\v1.0.x or v1.1.x directories, or verify via registry key HKLM\SOFTWARE\Microsoft\NET Framework\Setup\FullAffected if The installed version is ASP.NET 1.0 or 1.1 (versions 1.0.x or 1.1.x)
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Locate web.config filesSearch for web.config files in the application's root directory and any subdirectories. Each ASP.NET application may have its own web.configAffected if A web.config file exists in the affected application's directory
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Check enableViewStateMac settingOpen the web.config file and search for the enableViewStateMac attribute within the <pages> or <system.web> section. The setting appears as enableViewStateMac='true' or enableViewStateMac='false'Affected if enableViewStateMac is set to 'false' or is missing entirely (defaults to false in affected versions)
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Check viewstate encryption settingIn the same web.config, look for viewStateEncryptionMode attribute in the <pages> section. It may appear as viewStateEncryptionMode='Never', 'Always', or 'Auto'Affected if viewStateEncryptionMode is set to 'Never' or is not explicitly set to 'Always' and enableViewStateMac is disabled
A system is affected if it runs ASP.NET 1.0 or 1.1 AND has enableViewStateMac disabled or not set, allowing unauthenticated attackers to submit malicious viewstate causing server CPU exhaustion.
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 dataEnable viewstate validation and MAC checking in the application's web.config by setting enableViewStateMac='true' and enabling viewstate encryption to cryptographically sign viewstate data.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2005-1665 — 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-2005-1665 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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