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

Published Sep 5, 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 resresolverunbound 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 resresolverunbound by setting noload = resresolverunbound.so in modules.conf, or set rewritecontact = yes on all PJSIP endpoints. NOTE: This may not be appropriate for all Asterisk configurations.

Affected Software

35 affected componentsFixes available
Asterisk Asterisk<18.24.3, <20.9.3, <21.4.3
Asterisk certified-asterisk<18.9-cert12, <20.7-cert2
Sangoma Asterisk<18.24.3
Sangoma Asterisk>=20.0.0<20.9.3
Sangoma Asterisk>=21.0.0<=21.4.3
Sangoma Certified Asterisk<18.9
Sangoma Certified Asterisk=18.9
Sangoma Certified Asterisk=18.9-cert1
Sangoma Certified Asterisk=18.9-cert1-rc1
Sangoma Certified Asterisk=18.9-cert10
Sangoma Certified Asterisk=18.9-cert11
Sangoma Certified Asterisk=18.9-cert2
Sangoma Certified Asterisk=18.9-cert3
Sangoma Certified Asterisk=18.9-cert4
Sangoma Certified Asterisk=18.9-cert5
Sangoma Certified Asterisk=18.9-cert6
Sangoma Certified Asterisk=18.9-cert7
Sangoma Certified Asterisk=18.9-cert8
Sangoma Certified Asterisk=18.9-cert8-rc1
Sangoma Certified Asterisk=18.9-cert8-rc2
Sangoma Certified Asterisk=18.9-cert9
Sangoma Certified Asterisk=20.7-cert1
Sangoma Certified Asterisk=20.7-cert1-rc1
Sangoma Certified Asterisk=20.7-cert1-rc2
Sangoma Certified Asterisk=20.7-cert2
alpine/asterisk>=20.0.0<18.24.3-r0
18.24.3-r0
alpine/asterisk>=20.0.0<18.24.3-r0
18.24.3-r0
alpine/asterisk>=20.0.0<20.9.3-r0
20.9.3-r0
alpine/asterisk>=20.0.0<20.9.3-r0
20.9.3-r0
alpine/asterisk>=20.0.0<20.9.3-r0
20.9.3-r0
alpine/asterisk>=20.0.0<20.9.3-r0
20.9.3-r0
alpine/asterisk>=20.0.0<20.9.3-r0
20.9.3-r0
alpine/asterisk>=20.0.0<20.9.3-r0
20.9.3-r0
debian/asterisk<1:20.9.3~dfsg+~cs6.14.60671435-1
1:20.9.3~dfsg+~cs6.14.60671435-1
debian/asterisk
1:22.10.1+dfsg+~cs6.17.60671434-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade alpine/asterisk to a version that resolves this vulnerability.

    Fixed in 18.24.3-r0
  2. Upgrade

    Upgrade alpine/asterisk to a version that resolves this vulnerability.

    Fixed in 20.9.3-r0
  3. Upgrade

    Upgrade debian/asterisk to a version that resolves this vulnerability.

    Fixed in 1:20.9.3~dfsg+~cs6.14.60671435-1
  4. Upgrade

    Upgrade debian/asterisk to a version that resolves this vulnerability.

    Fixed in 1:22.10.1+dfsg+~cs6.17.60671434-1
  5. Upgrade

    Upgrade Asterisk to a version that resolves this vulnerability.

    Fixed in 18.24.3
  6. Upgrade

    Upgrade Asterisk to a version that resolves this vulnerability.

    Fixed in 20.9.3
  7. Upgrade

    Upgrade Asterisk to a version that resolves this vulnerability.

    Fixed in 21.4.3
  8. Upgrade

    Upgrade certified-asterisk to a version that resolves this vulnerability.

    Fixed in 18.9-cert12
  9. Upgrade

    Upgrade certified-asterisk to a version that resolves this vulnerability.

    Fixed in 20.7-cert2
  10. Configuration

    Set noload = res_resolver_unbound.so in modules.conf to disable res_resolver_unbound.

    Asterisk res_resolver_unbound noload = res_resolver_unbound.so
  11. Configuration

    Set rewrite_contact = yes on all PJSIP endpoints.

    Asterisk PJSIP endpoints rewrite_contact = yes

Event History

Sep 5, 2024
CVE Published
via MITRE·05:17 PM
Data Sourced
via MITRE·05:17 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Data Sourced
via OSV·06:15 PM
DescriptionSeverityAffected Software

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

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.

2

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.

3

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.

4

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.

5

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.

Company

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