high
7.5
CWE
362 703
Advisory Published
Updated

CVE-2023-49786: Asterisk susceptible to Denial of Service via DTLS Hello packets during call initiation

First published: Thu Dec 14 2023(Updated: )

Asterisk is an open source private branch exchange and telephony toolkit. In Asterisk prior to versions 18.20.1, 20.5.1, and 21.0.1; as well as certified-asterisk prior to 18.9-cert6; Asterisk is susceptible to a DoS due to a race condition in the hello handshake phase of the DTLS protocol when handling DTLS-SRTP for media setup. This attack can be done continuously, thus denying new DTLS-SRTP encrypted calls during the attack. Abuse of this vulnerability may lead to a massive Denial of Service on vulnerable Asterisk servers for calls that rely on DTLS-SRTP. Commit d7d7764cb07c8a1872804321302ef93bf62cba05 contains a fix, which is part of versions 18.20.1, 20.5.1, 21.0.1, amd 18.9-cert6.

Credit: security-advisories@github.com

Affected SoftwareAffected VersionHow to fix
Asterisk<18.20.1
Asterisk>=19.0.0<20.5.1
Asterisk=21.0.0
Asterisk=13.13.0
Asterisk=13.13.0-cert1
Asterisk=13.13.0-cert1-rc1
Asterisk=13.13.0-cert1-rc2
Asterisk=13.13.0-cert1-rc3
Asterisk=13.13.0-cert1-rc4
Asterisk=13.13.0-cert2
Asterisk=13.13.0-cert3
Asterisk=13.13.0-rc1
Asterisk=13.13.0-rc2
Asterisk=16.8.0
Asterisk=16.8.0-cert1
Asterisk=16.8.0-cert10
Asterisk=16.8.0-cert11
Asterisk=16.8.0-cert12
Asterisk=16.8.0-cert2
Asterisk=16.8.0-cert3
Asterisk=16.8.0-cert4
Asterisk=16.8.0-cert5
Asterisk=16.8.0-cert6
Asterisk=16.8.0-cert7
Asterisk=16.8.0-cert8
Asterisk=16.8.0-cert9
Asterisk=18.9-cert1
Asterisk=18.9-cert2
Asterisk=18.9-cert3
Asterisk=18.9-cert4
Asterisk=18.9-cert5

Remedy

https://github.com/asterisk/asterisk/commit/d7d7764cb07c8a1872804321302ef93bf62cba05

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2023-49786?

    CVE-2023-49786 is classified as a denial of service (DoS) vulnerability due to a race condition.

  • How do I fix CVE-2023-49786?

    To fix CVE-2023-49786, upgrade Asterisk to version 18.20.1, 20.5.1, 21.0.1, or the compatible certified-asterisk version 18.9-cert6 or later.

  • What versions are affected by CVE-2023-49786?

    CVE-2023-49786 affects Asterisk versions prior to 18.20.1, 20.5.1, 21.0.1, and certified-asterisk versions before 18.9-cert6.

  • What component in Asterisk is impacted by CVE-2023-49786?

    CVE-2023-49786 impacts the DTLS handshake phase in Asterisk, leading to a potential DoS condition.

  • Is CVE-2023-49786 easy to exploit?

    Given that it is a denial of service vulnerability resulting from a race condition, exploitation may require specific conditions during the DTLS handshake.

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