Virtual Event: Threat Detection and Incident Response Summit - Watch Sessions
Connect with us

Hi, what are you looking for?



Critical DoS Flaws Patched in Asterisk Framework

Updates released on Friday for the Asterisk communications framework address three critical denial-of-service (DoS) vulnerabilities discovered by Sandro Gauci, a penetration tester and researcher who specializes in VoIP and communications systems.

Updates released on Friday for the Asterisk communications framework address three critical denial-of-service (DoS) vulnerabilities discovered by Sandro Gauci, a penetration tester and researcher who specializes in VoIP and communications systems.

Asterisk, considered the world’s most popular open source communications framework, is used by government agencies, carriers and other businesses, including most Fortune 1000 companies. According to its developers, more than one million IP PBX systems, VoIP gateways, conference servers and other solutions rely on Asterisk.

In collaboration with Alfred Farrugia, Gauci discovered in April that the project is affected by three potentially serious vulnerabilities that can be exploited to cause the system to crash. Separate advisories have been published by Asterisk developers for each of the flaws, and Gauci has also released technical details

The vulnerabilities affect all versions of Asterisk 13, 14 and Certified Asterisk 13.13. The issues have been addressed with the release of versions 13.15.1, 14.4.1 and 13.13-cert4.

One of the security holes can be exploited by a remote attacker to cause Asterisk to exhaust all available memory by sending a specially crafted Signalling Connection Control Part (SCCP) packet. Removing or disabling support for the SCCP protocol prevents potential attacks.

“A remote memory exhaustion can be triggered by sending an SCCP packet to Asterisk system with ‘chan_skinny’ enabled that is larger than the length of the SCCP header but smaller than the packet length specified in the header. The loop that reads the rest of the packet doesn’t detect that the call to read() returned end-of-file before the expected number of bytes and continues infinitely. The ‘partial data’ message logging in that tight loop causes Asterisk to exhaust all available memory,” Asterisk developers wrote in their advisory.

The other two vulnerabilities found by Gauci affect PJSIP, an open source multimedia communication library that implements SIP (Session Initiation Protocol) and other protocols. The flaws can be exploited remotely to cause a crash by sending specially crafted SIP packets.

Advertisement. Scroll to continue reading.

The latest Asterisk releases include a version of PJSIP that addresses these vulnerabilities. However, other projects using the PJSIP library are vulnerable as well, and they will need to obtain upstream patches to protect their users against attacks.

*Updated with link to Gauci’s advisory 

Related Reading: HackerOne Offers Free Service to Open Source Projects

Related Reading: cURL Security Audit Reveals Several Vulnerabilities

Related Reading: Command Execution Vulnerability Patched in Ansible

Written By

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

SecurityWeek’s Threat Detection and Incident Response Summit brings together security practitioners from around the world to share war stories on breaches, APT attacks and threat intelligence.


Securityweek’s CISO Forum will address issues and challenges that are top of mind for today’s security leaders and what the future looks like as chief defenders of the enterprise.


Expert Insights

Related Content


Less than a week after announcing that it would suspended service indefinitely due to a conflict with an (at the time) unnamed security researcher...

Data Breaches

OpenAI has confirmed a ChatGPT data breach on the same day a security firm reported seeing the use of a component affected by an...

Risk Management

The supply chain threat is directly linked to attack surface management, but the supply chain must be known and understood before it can be...


The latest Chrome update brings patches for eight vulnerabilities, including seven reported by external researchers.


Patch Tuesday: Microsoft warns vulnerability (CVE-2023-23397) could lead to exploitation before an email is viewed in the Preview Pane.


Apple has released updates for macOS, iOS and Safari and they all include a WebKit patch for a zero-day vulnerability tracked as CVE-2023-23529.

IoT Security

A group of seven security researchers have discovered numerous vulnerabilities in vehicles from 16 car makers, including bugs that allowed them to control car...

Application Security

Drupal released updates that resolve four vulnerabilities in Drupal core and three plugins.