CVE-2017-17850 : What You Need to Know

A vulnerability has been found in versions of Asterisk prior to 13.18.4, 14.7.4, 15.1.4, and 13.18-cert1, where certain SIP messages can cause Asterisk to crash if a contact header is missing, especially when using the PJSIP channel driver. Enabling authentication can reduce the impact of this vulnerability.

Understanding CVE-2017-17850

This CVE relates to a specific vulnerability in Asterisk versions prior to 13.18.4, 14.7.4, 15.1.4, and 13.18-cert1.

What is CVE-2017-17850?

Asterisk, an open-source communications framework, is susceptible to crashing due to missing contact headers in certain SIP messages, particularly when using the PJSIP channel driver.

The Impact of CVE-2017-17850

The vulnerability can lead to Asterisk crashing, but enabling authentication can mitigate the severity by requiring user authorization before reaching the crash point.

Technical Details of CVE-2017-17850

This section provides more in-depth technical information about the CVE.

Vulnerability Description

The vulnerability arises from a lack of contact headers in specific SIP messages, causing crashes in Asterisk, especially with the PJSIP channel driver.

Affected Systems and Versions

Versions of Asterisk prior to 13.18.4, 14.7.4, 15.1.4, and 13.18-cert1

Exploitation Mechanism

Certain SIP messages without contact headers
Usage of the PJSIP channel driver

Mitigation and Prevention

Protecting systems from CVE-2017-17850 involves taking immediate and long-term security measures.

Immediate Steps to Take

Enable authentication in Asterisk
Regularly monitor for updates and patches

Long-Term Security Practices

Implement network segmentation to limit exposure
Conduct regular security audits and assessments

Patching and Updates

Update Asterisk to versions 13.18.4, 14.7.4, 15.1.4, or 13.18-cert1 to mitigate the vulnerability