CVE-2008-1923
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 IAX2 channel driver (chan_iax2) in Asterisk 1.2 before revision 72630 and 1.4 before revision 65679, when configured to allow unauthenticated calls, sends "early audio" to an unverified source IP address of a NEW message, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed NEW message.
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 IAX2 channel driver (chan_iax2) in Asterisk 1.2 and 1.4 versions sends early audio to an unverified source IP address from spoofed NEW messages when configured to allow unauthenticated calls, enabling remote attackers to amplify traffic for denial of service attacks.
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<= b2.5.1<= c1.8.0= a= b.1.3.2= b.1.3.3= b.2.2.0= b.2.2.1= b.2.3.1= b.2.3.2= b.2.3.3= b.2.3.4= b.2.5.0<= 1.0.2= 1.0= 1.0.1= 1.0= 1.0.0= 1.0.1= 1.0.2= 1.0.3= 1.0.4= 1.0.5= 1.0.6= 1.0.7= 1.0.8= 1.0.9= 1.0.11<= 1.1.0.2= 1.0= 1.0.1= 1.0.2= 1.0.3= 1.0.3.3= 1.1.0= 1.1.0.1CVSS 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
- M
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:M/Au:N/C:N/I:N/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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Determine installed Asterisk versionRun 'asterisk -V' or 'asterisk -x "core show version"' to get the exact version numberAffected if Version matches 1.0.x (1.0 through 1.0.11), or is 1.2.x or 1.4.x in the affected ranges
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Verify IAX2 module is loadedRun 'module show like chan_iax2' in the Asterisk CLI to check if the IAX2 channel driver is loadedAffected if The chan_iax2 module is loaded and running
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Inspect IAX2 configuration for unauthenticated call settingsExamine the iax.conf configuration file (typically in /etc/asterisk/ or /opt/asterisk/etc/) and look for 'allowguest=yes' or 'guest' section that permits unauthenticated connectionsAffected if The configuration contains 'allowguest=yes' or a 'guest' context that accepts unauthenticated calls
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Confirm IAX2 binding and reachable portCheck if UDP port 4569 (default IAX2 port) is open and listening using 'netstat -anp | grep 4569' or 'ss -anp | grep 4569'Affected if IAX2 port 4569 is open and Asterisk is accepting connections on it
The environment is affected if running an affected Asterisk version (1.0.x, 1.2.x, or 1.4.x), has the IAX2 module loaded, and is configured to accept unauthenticated guest calls via the IAX2 protocol.
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 unauthenticated call acceptance in the IAX2 configuration or upgrade Asterisk to version 1.2 revision 72630+ / 1.4 revision 65679+ where the vulnerability is patched.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2008-1923 — 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-2008-1923 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
- No spam, self-promotion, credentials, or personal data