CVE-2000-0804
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 · uneditedCheck Point VPN-1/FireWall-1 4.1 and earlier allows remote attackers to bypass the directionality check via fragmented TCP connection requests or reopening closed TCP connection requests, aka "One-way Connection Enforcement Bypass."
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 confidenceCheck Point VPN-1/FireWall-1 4.1 and earlier contains a vulnerability where remote attackers can bypass the one-way connection enforcement by sending fragmented TCP connection requests or reopening previously closed TCP connections, allowing traffic to flow in the prohibited direction.
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= 3.0= 4.0= 4.1CVSS 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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/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 installed Firewall-1 versionRun 'fw ver' or 'fwstat' command from the Check Point server, or check the installation directory for version files. On Windows, check Add/Remove Programs for the Check Point Firewall-1 version.Affected if The installed version is 3.0, 4.0, or 4.1 exactly.
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Locate one-way connection enforcement rulesOpen SmartDashboard or use 'fw policy' command to review security policies. Look for rules that define permitted connections in only one direction, often marked as 'one-way' or 'asymmetric' in the rule base.Affected if The firewall policy contains rules that enforce one-way TCP connections.
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Verify TCP state inspection configurationExamine the firewall's TCP inspection settings in the global properties or advanced settings. Check if 'TCP state inspection' or 'TCP reassembly' is enabled. Use 'fw ctl get int fwtcp_reassemble' if available.Affected if TCP fragmentation inspection or reassembly is not properly configured or is disabled.
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Check for established connection handling rulesReview the policy rules for any 'out-of-state' or 'established' connection exceptions. Look for settings that allow reopening previously closed connections or bypassing the state table.Affected if The policy allows exceptions for fragmented packets or out-of-state TCP packets.
A user is affected if their Firewall-1 version is 3.0, 4.0, or 4.1 AND they have one-way connection enforcement rules configured, as the vulnerability exploits how the firewall handles fragmented or reopened TCP connections in this setup.
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 version newer than FireWall-1 4.1, as Check Point has likely addressed this vulnerability in later releases. If upgrading is not immediately feasible, implement additional network segmentation or monitoring to detect anomalous connection patterns.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2000-0804 — 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-2000-0804 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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