CVE-2003-0520
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 · uneditedTrillian 1.0 Pro and 0.74 Freeware allows remote attackers to cause a denial of service (crash) via a TypingUser message in which the "TypingUser" string has been modified.
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 confidenceTrillian Instant Messenger versions 1.0 Pro and 0.74 Freeware contain a denial of service vulnerability in the handling of TypingUser messages. When a remote attacker sends a specially crafted TypingUser message with a modified 'TypingUser' string, the application crashes due to improper input validation in the message parsing routine.
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= 0.74= 1.0CVSS 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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Confirm Trillian installationCheck for Trillian installation directory (typically C:\Program Files\Trillian\ or C:\Program Files\Cerulean Studios\Trillian\) and verify the presence of trillian.exeAffected if Trillian executable is found on the system
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Identify installed Trillian versionRight-click trillian.exe, select Properties, then view the Version tab to obtain the exact product versionAffected if Version is reported as exactly 0.74 (Freeware) or exactly 1.0 (Pro)
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Verify Trillian is runningOpen Task Manager, look for trillian.exe in the Processes tab, or check if the Trillian process is listening on network ports (commonly AIM protocol ports)Affected if Trillian is actively running and connected to a network
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Check network exposureUse netstat -an to see if Trillian has open listening ports on local IP addresses, indicating it is accepting remote connectionsAffected if Trillian has open network ports accepting connections
A system is affected if Trillian version 0.74 or 1.0 is installed and actively running, as the DoS vulnerability is triggered by processing specially crafted TypingUser messages over the network.
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 dataThis is a legacy 2003 vulnerability in discontinued software. Users should migrate to modern instant messaging platforms as Trillian is no longer supported. If continued use is mandatory, network-level filtering of malformed TypingUser protocol messages may provide partial mitigation.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2003-0520 — 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-2003-0520 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