CVE-2021-26712 : Vulnerability Insights and Analysis

A vulnerability in Sangoma Asterisk versions allows a remote unauthenticated attacker to disrupt secure calls by replaying SRTP packets.

Understanding CVE-2021-26712

This CVE identifies an incorrect access control issue in Sangoma Asterisk versions that could be exploited by an attacker to terminate secure calls prematurely.

What is CVE-2021-26712?

The vulnerability in res_srtp.c in Sangoma Asterisk versions 13.38.1, 16.16.0, 17.9.1, and 18.2.0, and Certified Asterisk 16.8-cert5, enables an unauthorized remote attacker to disrupt secure calls by replaying SRTP packets.

The Impact of CVE-2021-26712

Exploitation of this vulnerability could lead to the premature termination of secure calls, impacting the confidentiality and integrity of communications over Asterisk systems.

Technical Details of CVE-2021-26712

The technical details of this CVE include:

Vulnerability Description

The issue arises from incorrect access controls in res_srtp.c, allowing unauthorized attackers to exploit SRTP packet replay to disrupt secure calls.

Affected Systems and Versions

Sangoma Asterisk versions 13.38.1, 16.16.0, 17.9.1, and 18.2.0, as well as Certified Asterisk 16.8-cert5, are impacted by this vulnerability.

Exploitation Mechanism

The vulnerability can be exploited by a remote unauthenticated attacker replaying SRTP packets to prematurely terminate secure calls.

Mitigation and Prevention

To address CVE-2021-26712, consider the following:

Immediate Steps to Take

Monitor for any unauthorized access or disruptions to secure calls.
Apply vendor-released patches or updates promptly.

Long-Term Security Practices

Regularly update Asterisk systems to the latest versions.
Implement strong access controls and encryption protocols to safeguard communication channels.

Patching and Updates

Refer to the vendor's security advisories and patches to address the vulnerability and enhance the security posture of Asterisk systems.