CVE-2016-9938
5.3 · MEDIUMOverview
CVE-2016-9938 is a medium-severity vulnerability affecting digium asterisk. It was published on December 12, 2016 and has a CVSS 3.0 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.0 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
An issue was discovered in Asterisk Open Source 11.x before 11.25.1, 13.x before 13.13.1, and 14.x before 14.2.1 and Certified Asterisk 11.x before 11.6-cert16 and 13.x before 13.8-cert4. The chan_sip channel driver has a liberal definition for whitespace when attempting to strip the content between a SIP header name and a colon character. Rather than following RFC 3261 and stripping only spaces and horizontal tabs, Asterisk treats any non-printable ASCII character as if it were whitespace. This means that headers such as Contact\x01: will be seen as a valid Contact header. This mostly does not pose a problem until Asterisk is placed in tandem with an authenticating SIP proxy. In such a case, a crafty combination of valid and invalid To headers can cause a proxy to allow an INVITE request into Asterisk without authentication since it believes the request is an in-dialog request. However, because of the bug described above, the request will look like an out-of-dialog request to Asterisk
Remediation
Check the references section for vendor advisories and patches from digium. Update asterisk to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
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Frequently Asked Questions
What is CVE-2016-9938?
CVE-2016-9938 is a medium-severity vulnerability affecting digium asterisk. It was published on December 12, 2016 and has a CVSS 3.0 base score of 5.3 (MEDIUM).
How severe is CVE-2016-9938?
This vulnerability has a CVSS 3.0 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2016-9938?
Check the references section for vendor advisories and patches from digium. Update asterisk to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2016-9938?
CyberStrike's AI-powered security agents can automatically detect CVE-2016-9938 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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