CVE-2020-35776 Explained : Impact and Mitigation

A buffer overflow vulnerability in Sangoma Asterisk versions 13.38.1, 16.15.1, 17.9.1, and 18.1.1 allows remote attackers to crash the system by manipulating SIP 181 responses.

Understanding CVE-2020-35776

This CVE involves a buffer overflow issue in Sangoma Asterisk versions, potentially leading to a system crash when exploited.

What is CVE-2020-35776?

The vulnerability in res_pjsip_diversion.c in Sangoma Asterisk versions allows attackers to crash the system by misusing SIP 181 responses.

The Impact of CVE-2020-35776

Exploitation of this vulnerability can result in a denial of service (DoS) condition, causing the Asterisk system to crash and become unresponsive.

Technical Details of CVE-2020-35776

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The buffer overflow in res_pjsip_diversion.c in Sangoma Asterisk versions enables remote attackers to crash the system by deliberately misusing SIP 181 responses.

Affected Systems and Versions

Sangoma Asterisk versions 13.38.1, 16.15.1, 17.9.1, and 18.1.1

Exploitation Mechanism

Attackers can exploit this vulnerability remotely by sending crafted SIP 181 responses, triggering a buffer overflow and crashing the system.

Mitigation and Prevention

Protecting systems from CVE-2020-35776 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply security patches provided by Sangoma for the affected Asterisk versions.
Monitor network traffic for any suspicious activity that could indicate an ongoing attack.
Implement network segmentation to limit the impact of potential exploits.

Long-Term Security Practices

Regularly update and patch all software and systems to prevent known vulnerabilities.
Conduct security assessments and penetration testing to identify and address weaknesses proactively.

Patching and Updates

Stay informed about security advisories and updates from Sangoma to apply patches promptly and ensure system security.