CVE-2008-6564
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 · uneditedNortel UNIStim protocol, as used in Communication Server 1000 and other products, uses predictable sequence numbers, which allows remote attackers to hijack sessions via sniffing or brute force attacks.
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 Nortel UNIStim protocol (used in Communication Server 1000 and related products) employs predictable sequence numbers in its communication, enabling remote attackers to hijack active sessions through packet sniffing followed by brute force attacks to determine valid sequence numbers.
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 versionsall versionsCVSS 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 UNIStim protocol usageInventory the network for Nortel Communication Server 1000, Nortel IP phones, or devices using the UNIStim protocol. Check for port 5000 (default UNIStim port) in use and identify any Nortel VOIP equipment on the network.Affected if Nortel Communication Server 1000 or any UNIStim-based devices are present in the environment
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Capture UNIStim trafficUse a packet capture tool (such as tcpdump or Wireshark) to capture packets on the UDP port used for UNIStim communication (typically port 5000). Filter for packets originating from Nortel phones or the Communication Server.Affected if UNIStim traffic is observed on the network
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Analyze sequence number patternsExamine the captured UNIStim packets and inspect the sequence number field in the protocol headers. Compare multiple packets to determine if the numbers increment predictably (e.g., 1, 2, 3, 4...) or follow a deterministic pattern.Affected if Sequence numbers are sequential, predictable, or follow a deterministic increment pattern rather than appearing randomized
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Check Communication Server versionQuery the Nortel Communication Server 1000 for its software version through administrative interfaces, SNMP, or vendor documentation. Compare the installed version against any patched releases that implement randomized sequence numbers.Affected if The Communication Server version does not include sequence number randomization or the version cannot be determined to have this protection
The environment is affected if Nortel Communication Server 1000 or UNIStim protocol devices are deployed and the captured traffic shows predictable/sequential sequence numbers rather than randomized values.
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 patched Nortel Communication Server versions that implement randomized sequence numbers; if patches are unavailable, consider network segmentation to limit exposure and implement additional authentication layers for VOIP traffic.
- Consultation12.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA8.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2008-6564 — 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-2008-6564 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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