CVE-2009-0077
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 firewall engine in Microsoft Forefront Threat Management Gateway, Medium Business Edition (TMG MBE); and Internet Security and Acceleration (ISA) Server 2004 SP3, 2006, 2006 Supportability Update, and 2006 SP1; does not properly manage the session state of web listeners, which allows remote attackers to cause a denial of service (many stale sessions) via crafted packets, aka "Web Proxy TCP State Limited Denial of Service Vulnerability."
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 confidenceThe firewall engine in Microsoft Forefront TMG MBE and ISA Server 2004/2006 fails to properly manage the session state of web listeners. Remote attackers can send crafted packets to create many stale sessions, causing a denial of service condition.
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 versions= 2004= 2006CVSS 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 Microsoft security productsCheck installed programs in Control Panel or review registry key HKLM\SOFTWARE\Microsoft\ServerManager\ServStorage for ISA Server or Forefront TMG componentsAffected if Microsoft Internet Security and Acceleration Server 2004, 2006, or Forefront Threat Management Gateway is listed as installed
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Determine installed versionRun 'reg query "HKLM\SOFTWARE\Microsoft\FPC" /v Version' or check the version property of the ISA Server or TMG service in Services.mscAffected if Version matches ISA Server 2004 or 2006, or any version of Forefront TMG
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Verify firewall service is runningOpen Services.msc and check if 'Microsoft Firewall' or 'ISA Server' service is in a Running stateAffected if The firewall service is enabled and running, exposing the vulnerable session management code
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Check for session exhaustion symptomsMonitor the firewall service or performance counters for unusually high number of concurrent connections or session table entries that do not clearAffected if Session count remains elevated without dropping after connections close, indicating stale session accumulation
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Review firewall logs for anomalous traffic patternsExamine ISA Server or TMG firewall logs for repeated connection attempts from external IPs that correlate with session spikesAffected if Large volume of connections from few external sources creating session entries faster than normal traffic patterns
You are affected if ISA Server 2004/2006 or any Forefront TMG version is installed with the firewall service enabled, as the vulnerability exists in all versions of these products.
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 dataApply Microsoft security patches for this vulnerability. For end-of-life products (ISA Server 2004/2006, TMG MBE), migrate to supported Microsoft security solutions such as modern Forefront TMG or Azure WAF.
- Consultation4.0 h
- Implementation4.0 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 $3,968.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2009-0077 — 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-2009-0077 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data