CVE-2021-37624 : Exploit Details and Defense Strategies

FreeSWITCH is a Software Defined Telecom Stack that did not authenticate SIP MESSAGE requests before version 1.10.7, allowing spam and message spoofing.

Understanding CVE-2021-37624

This CVE relates to a vulnerability in FreeSWITCH that could be exploited to send unauthenticated SIP MESSAGE requests, potentially enabling spam and message spoofing.

What is CVE-2021-37624?

FreeSWITCH version < 1.10.7 did not authenticate SIP MESSAGE requests, leading to security risks such as spam, social engineering, and phishing attacks.

The Impact of CVE-2021-37624

The vulnerability could allow attackers to send messages to user agents registered with the server without authentication, posing risks of message spoofing and enabling various malicious activities.

Technical Details of CVE-2021-37624

The vulnerability primarily stemmed from the lack of authentication for SIP MESSAGE requests in FreeSWITCH versions prior to 1.10.7.

Vulnerability Description

FreeSWITCH did not authenticate SIP MESSAGE requests, allowing unauthenticated parties to send messages to registered user agents.

Affected Systems and Versions

Product: FreeSWITCH
Vendor: SignalWire
Versions Affected: < 1.10.7

Exploitation Mechanism

Abuse of this security issue could enable attackers to send unauthenticated SIP MESSAGE requests to any registered user agent without proper verification, potentially leading to spam, social engineering, and phishing attacks.

Mitigation and Prevention

To mitigate the risks associated with CVE-2021-37624, immediate steps should be taken along with long-term security practices and timely patching:

Immediate Steps to Take

Upgrade FreeSWITCH to version 1.10.7 or above to patch the vulnerability
Ensure that SIP MESSAGE requests are authenticated by default

Long-Term Security Practices

Regularly update FreeSWITCH to the latest versions to avoid known vulnerabilities
Implement network segmentation and access controls for additional security

Patching and Updates

Refer to the official FreeSWITCH website or repositories for patches, updates, and security advisories.