CVE-1999-0955
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 · uneditedRace condition in wu-ftpd and BSDI ftpd allows remote attackers to gain root access via the SITE EXEC command.
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 confidenceA race condition vulnerability exists in wu-ftpd and BSDI ftpd servers that allows remote attackers to gain root privileges through the SITE EXEC command. The vulnerability stems from improper handling of the SITE EXEC functionality, which permits arbitrary command execution on the target system.
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= 2.4.1CVSS 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
- High
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:H/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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Identify the running FTP server and its versionConnect to the FTP service and issue a banner check (e.g., `ftp <target>` or inspect the service banner via `nc <target> 21`). Alternatively, check the FTP daemon binary or process (e.g., `ps aux | grep ftpd` or examine `/usr/sbin/ftpd`).Affected if The banner or binary identifies the server as Washington University Wu Ftpd version 2.4.1 specifically, or any unpatched wu-ftpd variant reporting version 2.4.x.
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Locate the wu-ftpd configuration fileCommon configuration paths include `/etc/ftpaccess`, `/etc/ftpd/ftpaccess`, or `/etc/wu-ftpd/ftpaccess`. Check the ftpd startup scripts or man pages for the exact path on your system.Affected if The configuration file exists and contains directives for wu-ftpd, confirming the server in use.
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Determine if SITE EXEC is enabledSearch the FTP configuration file (e.g., `ftpaccess`) for the `site exec` or `site allow` directives. In wu-ftpd, SITE EXEC is typically controlled via lines like `site exec` or `site allow exec`. Check for any restrictions on SITE EXEC functionality.Affected if The configuration contains `site exec` or equivalent directives that permit SITE EXEC, or no explicit restriction denying it.
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Verify the SITE EXEC command behaviorIf you have access to test the FTP server (with authorized access), attempt to issue the SITE EXEC command (e.g., `SITE EXEC whoami`) and observe whether the server accepts and processes it. Alternatively, review server logs for SITE EXEC usage.Affected if The server accepts and attempts to execute the SITE EXEC command, indicating the vulnerable feature is active.
Your environment is affected if the running FTP server is Washington University Wu Ftpd version 2.4.1 (or an unpatched 2.4.x variant) with the SITE EXEC command enabled in the configuration.
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 or restrict the SITE EXEC command in the FTP server configuration, or migrate to a modern FTP server that does not support this legacy and dangerous command. If wu-ftpd or BSDI ftpd must be used, apply available patches or upgrades.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-1999-0955 — 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-1999-0955 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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