In res/res_rtp_asterisk.c in Asterisk 11.x before 11.25.2, 13.x before 13.17.1, and 14.x before 14.6.1 and Certified Asterisk 11.x before 11.6-cert17 and 13.x before 13.13-cert5, unauthorized data disclosure (media takeover in the RTP stack) is possible with careful timing by an attacker. The "strictrtp" option in rtp.conf enables a feature of the RTP stack that learns the source address of media for a session and drops any packets that do not originate from the expected address. This option is enabled by default in Asterisk 11 and above. The "nat" and "rtp_symmetric" options (for chan_sip and chan_pjsip, respectively) enable symmetric RTP support in the RTP stack. This uses the source address of incoming media as the target address of any sent media. This option is not enabled by default, but is commonly enabled to handle devices behind NAT. A change was made to the strict RTP support in the RTP stack to better tolerate late media when a reinvite occurs. When combined with the symmetric RTP support, this introduced an avenue where media could be hijacked. Instead of only learning a new address when expected, the new code allowed a new source address to be learned at all times. If a flood of RTP traffic was received, the strict RTP support would allow the new address to provide media, and (with symmetric RTP enabled) outgoing traffic would be sent to this new address, allowing the media to be hijacked. Provided the attacker continued to send traffic, they would continue to receive traffic as well.
| Software | From | Fixed in |
|---|---|---|
| digium / asterisk | 13.1.0 | 13.1.0.x |
| digium / asterisk | 13.1.0-rc2 | 13.1.0-rc2.x |
| digium / asterisk | 13.2.1 | 13.2.1.x |
| digium / asterisk | 13.8.0-rc1 | 13.8.0-rc1.x |
| digium / asterisk | 13.15.0-rc2 | 13.15.0-rc2.x |
| digium / asterisk | 13.7.0-rc1 | 13.7.0-rc1.x |
| digium / asterisk | 13.7.0-rc2 | 13.7.0-rc2.x |
| digium / asterisk | 13.7.1 | 13.7.1.x |
| digium / asterisk | 13.1.0-rc1 | 13.1.0-rc1.x |
| digium / asterisk | 13.12 | 13.12.x |
| digium / asterisk | 13.15.0-rc1 | 13.15.0-rc1.x |
| digium / asterisk | 13.1.1 | 13.1.1.x |
| digium / asterisk | 13.14.0-rc2 | 13.14.0-rc2.x |
| digium / asterisk | 13.4.0 | 13.4.0.x |
| digium / asterisk | 13.15.0-rc3 | 13.15.0-rc3.x |
| digium / asterisk | 13.17.0-rc1 | 13.17.0-rc1.x |
| digium / asterisk | 13.2.0 | 13.2.0.x |
| digium / asterisk | 13.3.2 | 13.3.2.x |
| digium / asterisk | 13.0.1 | 13.0.1.x |
| digium / asterisk | 13.10.0-rc1 | 13.10.0-rc1.x |
| digium / asterisk | 13.10.0 | 13.10.0.x |
| digium / asterisk | 13.6.0-rc1 | 13.6.0-rc1.x |
| digium / asterisk | 13.2.0-rc1 | 13.2.0-rc1.x |
| digium / asterisk | 13.8.0 | 13.8.0.x |
| digium / asterisk | 13.0.0 | 13.0.0.x |
| digium / asterisk | 13.11.1 | 13.11.1.x |
| digium / asterisk | 13.13.1 | 13.13.1.x |
| digium / asterisk | 13.17.0 | 13.17.0.x |
| digium / asterisk | 13.11.0 | 13.11.0.x |
| digium / asterisk | 13.9.0 | 13.9.0.x |
| digium / asterisk | 13.12.0 | 13.12.0.x |
| digium / asterisk | 13.8.1 | 13.8.1.x |
| digium / asterisk | 13.12.2 | 13.12.2.x |
| digium / asterisk | 13.0.0-beta1 | 13.0.0-beta1.x |
| digium / asterisk | 13.13.0 | 13.13.0.x |
| digium / asterisk | 13.15.1 | 13.15.1.x |
| digium / asterisk | 13.16.0-rc2 | 13.16.0-rc2.x |
| digium / asterisk | 13.9.1 | 13.9.1.x |
| digium / asterisk | 13.0.2 | 13.0.2.x |
| digium / asterisk | 13.14.1 | 13.14.1.x |
| digium / asterisk | 13.7.2 | 13.7.2.x |
| digium / asterisk | 13.4.0-rc1 | 13.4.0-rc1.x |
| digium / asterisk | 13.3.0-rc1 | 13.3.0-rc1.x |
| digium / asterisk | 13.11.2 | 13.11.2.x |
| digium / asterisk | 13.13 | 13.13.x |
| digium / asterisk | 13.12.1 | 13.12.1.x |
| digium / asterisk | 13.5.0 | 13.5.0.x |
| digium / asterisk | 13.8.2 | 13.8.2.x |
| digium / asterisk | 13.0.0-beta3 | 13.0.0-beta3.x |
| digium / asterisk | 13.14.0 | 13.14.0.x |
| digium / asterisk | 13.15.0 | 13.15.0.x |
| digium / asterisk | 13.5.0-rc1 | 13.5.0-rc1.x |
| digium / asterisk | 13.14.0-rc1 | 13.14.0-rc1.x |
| digium / asterisk | 13.0.0-beta2 | 13.0.0-beta2.x |
| digium / asterisk | 13.16.0-rc1 | 13.16.0-rc1.x |
| digium / asterisk | 13.16.0 | 13.16.0.x |
| digium / asterisk | 14.3.0 | 14.3.0.x |
| digium / asterisk | 14.4.1 | 14.4.1.x |
| digium / asterisk | 14.6.0 | 14.6.0.x |
| digium / asterisk | 14.2.1 | 14.2.1.x |
| digium / asterisk | 14.6.0-rc1 | 14.6.0-rc1.x |
| digium / asterisk | 14.02 | 14.02.x |
| digium / asterisk | 14.5.0-rc2 | 14.5.0-rc2.x |
| digium / asterisk | 14.0.0-beta1 | 14.0.0-beta1.x |
| digium / asterisk | 14.1.1 | 14.1.1.x |
| digium / asterisk | 14.3.0-rc2 | 14.3.0-rc2.x |
| digium / asterisk | 14.4.0-rc1 | 14.4.0-rc1.x |
| digium / asterisk | 14.4.0-rc3 | 14.4.0-rc3.x |
| digium / asterisk | 14.4.0-rc2 | 14.4.0-rc2.x |
| digium / asterisk | 14.0.0-rc1 | 14.0.0-rc1.x |
| digium / asterisk | 14.2.0 | 14.2.0.x |
| digium / asterisk | 14.0.0 | 14.0.0.x |
| digium / asterisk | 14.1.2 | 14.1.2.x |
| digium / asterisk | 14.0 | 14.0.x |
| digium / asterisk | 14.3.0-rc1 | 14.3.0-rc1.x |
| digium / asterisk | 14.0.2 | 14.0.2.x |
| digium / asterisk | 14.0.0-rc2 | 14.0.0-rc2.x |
| digium / asterisk | 14.4.0 | 14.4.0.x |
| digium / asterisk | 14.0.0-beta2 | 14.0.0-beta2.x |
| digium / asterisk | 14.0.1 | 14.0.1.x |
| digium / asterisk | 14.5.0-rc1 | 14.5.0-rc1.x |
| digium / asterisk | 14.1 | 14.1.x |
| digium / asterisk | 14.5.0 | 14.5.0.x |
| digium / asterisk | 14.1.0 | 14.1.0.x |
| digium / asterisk | 14.01 | 14.01.x |
| digium / asterisk | 14.3.1 | 14.3.1.x |
| digium / asterisk | 14.2 | 14.2.x |
| digium / asterisk | 11.22.0 | 11.22.0.x |
| digium / asterisk | 11.10.2 | 11.10.2.x |
| digium / asterisk | 11.8.0 | 11.8.0.x |
| digium / asterisk | 11.0.0-rc2 | 11.0.0-rc2.x |
| digium / asterisk | 11.1.1 | 11.1.1.x |
| digium / asterisk | 11.21.1 | 11.21.1.x |
| digium / asterisk | 11.17.0-rc1 | 11.17.0-rc1.x |
| digium / asterisk | 11.14.0-rc2 | 11.14.0-rc2.x |
| digium / asterisk | 11.10.1 | 11.10.1.x |
| digium / asterisk | 11.11.0 | 11.11.0.x |
| digium / asterisk | 11.19.0-rc1 | 11.19.0-rc1.x |
| digium / asterisk | 11.12.1 | 11.12.1.x |
| digium / asterisk | 11.23.0-rc1 | 11.23.0-rc1.x |
| digium / asterisk | 11.0.2 | 11.0.2.x |
| digium / asterisk | 11.9.0-rc2 | 11.9.0-rc2.x |
| digium / asterisk | 11.2.0-rc1 | 11.2.0-rc1.x |
| digium / asterisk | 11.15.0-rc2 | 11.15.0-rc2.x |
| digium / asterisk | 11.14.0 | 11.14.0.x |
| digium / asterisk | 11.0.0-beta1 | 11.0.0-beta1.x |
| digium / asterisk | 11.25.1 | 11.25.1.x |
| digium / asterisk | 11.18.0 | 11.18.0.x |
| digium / asterisk | 11.7.0 | 11.7.0.x |
| digium / asterisk | 11.22.0-rc1 | 11.22.0-rc1.x |
| digium / asterisk | 11.23.1 | 11.23.1.x |
| digium / asterisk | 11.12.0 | 11.12.0.x |
| digium / asterisk | 11.12.0-rc1 | 11.12.0-rc1.x |
| digium / asterisk | 11.15.1 | 11.15.1.x |
| digium / asterisk | 11.6.0-rc1 | 11.6.0-rc1.x |
| digium / asterisk | 11.10.1-rc1 | 11.10.1-rc1.x |
| digium / asterisk | 11.0.0 | 11.0.0.x |
| digium / asterisk | 11.10.0 | 11.10.0.x |
| digium / asterisk | 11.8.0-rc1 | 11.8.0-rc1.x |
| digium / asterisk | 11.25.0 | 11.25.0.x |
| digium / asterisk | 11.4.0-rc4 | 11.4.0-rc4.x |
| digium / asterisk | 11.13.0 | 11.13.0.x |
| digium / asterisk | 11.15.0-rc1 | 11.15.0-rc1.x |
| digium / asterisk | 11.24.1 | 11.24.1.x |
| digium / asterisk | 11.1.0-rc3 | 11.1.0-rc3.x |
| digium / asterisk | 11.8.1 | 11.8.1.x |
| digium / asterisk | 11.1.0-rc2 | 11.1.0-rc2.x |
| digium / asterisk | 11.1.2 | 11.1.2.x |
| digium / asterisk | 11.21.2 | 11.21.2.x |
| digium / asterisk | 11.14.2 | 11.14.2.x |
| digium / asterisk | 11.9.0-rc3 | 11.9.0-rc3.x |
| digium / asterisk | 11.16.0-rc1 | 11.16.0-rc1.x |
| digium / asterisk | 11.2.2 | 11.2.2.x |
| digium / asterisk | 11.18.0-rc1 | 11.18.0-rc1.x |
| digium / asterisk | 11.21.0-rc2 | 11.21.0-rc2.x |
| digium / asterisk | 11.14.1 | 11.14.1.x |
| digium / asterisk | 11.1.0 | 11.1.0.x |
| digium / asterisk | 11.21.0-rc1 | 11.21.0-rc1.x |
| digium / asterisk | 11.11.0-rc1 | 11.11.0-rc1.x |
| digium / asterisk | 11.10.0-rc1 | 11.10.0-rc1.x |
| digium / asterisk | 11.7.0-rc2 | 11.7.0-rc2.x |
| digium / asterisk | 11.17.1 | 11.17.1.x |
| digium / asterisk | 11.0.0-beta2 | 11.0.0-beta2.x |
| digium / asterisk | 11.1.0-rc1 | 11.1.0-rc1.x |
| digium / asterisk | 11.0.1 | 11.0.1.x |
| digium / asterisk | 11.20.0-rc1 | 11.20.0-rc1.x |
| digium / asterisk | 11.8.0-rc3 | 11.8.0-rc3.x |
| digium / asterisk | 11.6.0 | 11.6.0.x |
| digium / asterisk | 11.23.0 | 11.23.0.x |
| digium / asterisk | 11.6.0-rc2 | 11.6.0-rc2.x |
| digium / asterisk | 11.24.0 | 11.24.0.x |
| digium / asterisk | 11.14.0-rc1 | 11.14.0-rc1.x |
| digium / asterisk | 11.7.0-rc1 | 11.7.0-rc1.x |
| digium / asterisk | 11.9.0 | 11.9.0.x |
| digium / asterisk | 11.2.1 | 11.2.1.x |
| digium / asterisk | 11.13.1 | 11.13.1.x |
| digium / asterisk | 11.9.0-rc1 | 11.9.0-rc1.x |
| digium / asterisk | 11.8.0-rc2 | 11.8.0-rc2.x |
| digium / asterisk | 11.13.0-rc1 | 11.13.0-rc1.x |
| digium / asterisk | 11.6.1 | 11.6.1.x |
| digium / asterisk | 11.0.0-rc1 | 11.0.0-rc1.x |
| digium / certified_asterisk | 11.6-cert6 | 11.6-cert6.x |
| digium / certified_asterisk | 11.6-cert14_rc1 | 11.6-cert14_rc1.x |
| digium / certified_asterisk | 11.6-cert15 | 11.6-cert15.x |
| digium / certified_asterisk | 11.6-cert3 | 11.6-cert3.x |
| digium / certified_asterisk | 11.6-cert14 | 11.6-cert14.x |
| digium / certified_asterisk | 11.6-cert1 | 11.6-cert1.x |
| digium / certified_asterisk | 11.6-cert1_rc2 | 11.6-cert1_rc2.x |
| digium / certified_asterisk | 11.6-cert2 | 11.6-cert2.x |
| digium / certified_asterisk | 11.6-cert16 | 11.6-cert16.x |
| digium / certified_asterisk | 11.6-cert9 | 11.6-cert9.x |
| digium / certified_asterisk | 11.6-cert4 | 11.6-cert4.x |
| digium / certified_asterisk | 11.6-cert5 | 11.6-cert5.x |
| digium / certified_asterisk | 11.6-cert10 | 11.6-cert10.x |
| digium / certified_asterisk | 11.6-cert11 | 11.6-cert11.x |
| digium / certified_asterisk | 11.6-cert1_rc1 | 11.6-cert1_rc1.x |
| digium / certified_asterisk | 11.6-cert14_rc2 | 11.6-cert14_rc2.x |
| digium / certified_asterisk | 11.6-cert7 | 11.6-cert7.x |
| digium / certified_asterisk | 11.6-cert13 | 11.6-cert13.x |
| digium / certified_asterisk | 11.6-cert8 | 11.6-cert8.x |
| digium / certified_asterisk | 11.6-cert12 | 11.6-cert12.x |
| digium / certified_asterisk | 13.13-cert1 | 13.13-cert1.x |
| digium / certified_asterisk | 13.13-cert1_rc1 | 13.13-cert1_rc1.x |
| digium / certified_asterisk | 13.13-cert1_rc4 | 13.13-cert1_rc4.x |
| digium / certified_asterisk | 13.13-cert1_rc3 | 13.13-cert1_rc3.x |
| digium / certified_asterisk | 13.13-cert2 | 13.13-cert2.x |
| digium / certified_asterisk | 13.13-cert3 | 13.13-cert3.x |
| digium / certified_asterisk | 13.13-cert4 | 13.13-cert4.x |
| digium / certified_asterisk | 13.13-cert1_rc2 | 13.13-cert1_rc2.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.