CVE-2023-27599 : Exploit Details and Defense Strategies

This CVE record discusses a vulnerability in OpenSIPS related to the

parse_to_param()

function.

Understanding CVE-2023-27599

This vulnerability affects OpenSIPS, a Session Initiation Protocol (SIP) server implementation. The issue arises in versions prior to 3.1.7 and 3.2.4, where a specific function mishandles a SIP message, causing a crash due to a call to the

abort()

function.

What is CVE-2023-27599?

The vulnerability in OpenSIPS occurs when the function

append_hf

processes a SIP message with a malformed To header, triggering a crash. This vulnerability allows an attacker to exploit the system, resulting in a Denial of Service (DoS) attack.

The Impact of CVE-2023-27599

Exploiting this vulnerability can lead to a complete denial of service, disrupting SIP server operations and potentially causing service downtime for users relying on OpenSIPS.

Technical Details of CVE-2023-27599

This section delves deeper into the technical aspects of the CVE.

Vulnerability Description

The vulnerability stems from improper handling of a SIP message with a malformed To header by the

append_hf

function in OpenSIPS. This triggers a call to the

abort()

function, leading to a system crash.

Affected Systems and Versions

Systems running OpenSIPS versions earlier than 3.1.7 and 3.2.4 are impacted by this vulnerability. Specifically, versions

< 3.1.7

and

>= 3.2.0, < 3.2.4

are susceptible to the issue.

Exploitation Mechanism

By crafting a specific SIP message with a malformed To header, attackers can exploit the vulnerability in OpenSIPS to trigger the

abort()

function and cause a crash, resulting in a denial of service.

Mitigation and Prevention

To address CVE-2023-27599 and mitigate its impact, immediate steps and long-term security practices are recommended.

Immediate Steps to Take

Update OpenSIPS to versions 3.1.7 or 3.2.4 to patch the vulnerability and prevent exploitation. Additionally, review configurations to ensure no functions that make use of the affected code, such as

append_hf

, are present.

Long-Term Security Practices

Regularly monitor for security updates and patches from OpenSIPS to stay protected against emerging vulnerabilities. Implement rigorous security testing to identify and address potential weaknesses in SIP server implementations.

Patching and Updates

Stay updated on security advisories and apply patches promptly to safeguard your OpenSIPS deployment. Regularly review and update configurations to align with best practices for secure SIP server operation.