CVE-2024-42491: A malformed Contact or Record-Route URI in an incoming SIP request can cause Asterisk to crash when res_resolver_unbound is used
First published: Thu Sep 05 2024(Updated: )
Asterisk is an open-source private branch exchange (PBX). Prior to versions 18.24.3, 20.9.3, and 21.4.3 of Asterisk and versions 18.9-cert12 and 20.7-cert2 of certified-asterisk, if Asterisk attempts to send a SIP request to a URI whose host portion starts with `.1` or `[.1]`, and res_resolver_unbound is loaded, Asterisk will crash with a SEGV. To receive a patch, users should upgrade to one of the following versions: 18.24.3, 20.9.3, 21.4.3, certified-18.9-cert12, certified-20.7-cert2. Two workarounds are available. Disable res_resolver_unbound by setting `noload = res_resolver_unbound.so` in modules.conf, or set `rewrite_contact = yes` on all PJSIP endpoints. NOTE: This may not be appropriate for all Asterisk configurations.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Asterisk | <18.24.3<20.9.3<21.4.3 | |
| Asterisk Certified Asterisk | <18.9-cert12<20.7-cert2 |
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Reference Links
- https://github.com/asterisk/asterisk/security/advisories/GHSA-v428-g3cw-7hv9
- https://github.com/asterisk/asterisk/commit/42a2f4ccfa2c7062a15063e765916b3332e34cc4
- https://github.com/asterisk/asterisk/commit/4f01669c7c41c9184f3cce9a3cf1b2ebf6201742
- https://github.com/asterisk/asterisk/commit/50bf8d4d3064930d28ecf1ce3397b14574d514d2
- https://github.com/asterisk/asterisk/commit/7a0090325bfa9d778a39ae5f7d0a98109e4651c8
- https://github.com/asterisk/asterisk/commit/a15050650abf09c10a3c135fab148220cd41d3a0
Frequently Asked Questions
What is the severity of CVE-2024-42491?
The severity of CVE-2024-42491 is classified as moderate, posing potential risks for Asterisk installations that utilize specific SIP request formats.
How do I fix CVE-2024-42491?
To mitigate CVE-2024-42491, upgrade your Asterisk to versions 18.24.3, 20.9.3, or 21.4.3, or for certified Asterisk, update to versions 18.9-cert12 or 20.7-cert2.
What versions of Asterisk are affected by CVE-2024-42491?
CVE-2024-42491 affects Asterisk versions prior to 18.24.3, 20.9.3, and 21.4.3, as well as certified-asterisk versions before 18.9-cert12 and 20.7-cert2.
What consequence does CVE-2024-42491 pose for users?
CVE-2024-42491 may lead to unexpected behavior when Asterisk processes SIP requests directed at certain URI formats.
Is there a workaround for CVE-2024-42491?
There are no documented workarounds for CVE-2024-42491; updating to a patched version is the recommended solution.
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