CVE-2023-27596 Explained : Impact and Mitigation

This CVE record discloses a vulnerability with the identifier CVE-2023-27596 in OpenSIPS, a Session Initiation Protocol (SIP) server implementation. The vulnerability was discovered by GitHub_M and has been assigned a high severity score.

Understanding CVE-2023-27596

The vulnerability in OpenSIPS exists in the

codec_delete_XX()

functions prior to versions 3.1.8 and 3.2.5. It is categorized under CWE-770, which involves the allocation of resources without limits or throttling.

What is CVE-2023-27596?

OpenSIPS faces a critical issue where it crashes when receiving a malformed SDP body multiple times on a configuration using the

stream_process

function. This flaw was detected during coverage-guided fuzzing of the

codec_delete_except_re

function. Exploiting this vulnerability allows an attacker to crash the server, impacting configurations utilizing functions like

codec_delete_except_re

.

The Impact of CVE-2023-27596

Due to this vulnerability, an unauthorized attacker can cause a denial of service (DoS) by crashing the OpenSIPS server. This can lead to service disruption and unavailability, posing a significant threat to the system's availability.

Technical Details of CVE-2023-27596

The technical metrics for this CVE indicate a base severity score of 7.5, classifying it as a high severity vulnerability. The CVSS v3.1 score details an attack vector of NETWORK with high availability impact and low attack complexity.

Vulnerability Description

The flaw in OpenSIPS arises when processing malformed SDP bodies, resulting in server crashes under specific configurations. It stems from insufficient input validation, allowing repeated submission of the malicious payload.

Affected Systems and Versions

OpenSIPS versions prior to 3.1.8 and 3.2.5 are vulnerable to this issue. Specifically, versions below 3.1.8 and between 3.2.0 and 3.2.5 are impacted, making it crucial for users to update to patched versions to mitigate the risk.

Exploitation Mechanism

By sending crafted SDP bodies multiple times to an OpenSIPS configuration utilizing the

stream_process

function, an attacker can trigger the server crash, exploiting the vulnerability in the

codec_delete_except_re

function.

Mitigation and Prevention

To address CVE-2023-27596, immediate actions and long-term security practices are essential to safeguard OpenSIPS deployments.

Immediate Steps to Take

Users of OpenSIPS should update their installations to version 3.1.8 or 3.2.5 to mitigate the vulnerability. Additionally, it is recommended to monitor and restrict network access to minimize the risk of exploitation.

Long-Term Security Practices

Implementing secure coding practices, conducting regular security assessments, and staying informed about security updates are crucial for maintaining a secure OpenSIPS deployment. Employing comprehensive security measures can help prevent and detect similar vulnerabilities in the future.

Patching and Updates

OpenSIPS users should regularly check for security advisories and apply patches promptly to address known vulnerabilities. Timely updates and proactive risk management are vital to ensuring the security and stability of OpenSIPS implementations.