NVD
- Id
- 22531
- Name
- CVE-2016-9938
- 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 Contactx01: 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. Asterisk will then process the request as a new call. The result is that Asterisk can process calls from unvetted sources without any authentication. If you do not use a proxy for authentication, then this issue does not affect you. If your proxy is dialog-aware (meaning that the proxy keeps track of what dialogs are currently valid), then this issue does not affect you. If you use chan_pjsip instead of chan_sip, then this issue does not affect you.
- Reject
- CVSS Version
- 2
- CVSS Score
- 5
- Severity
- Medium
- CVSS Base Score
- 5
- CVSS Impact Subscore
- 2.9
- CVSS Exploit Subscore
- 10
- CVSS Vector
- (AV:N/AC:L/Au:N/C:N/I:P/A:N)
- Pub Date
- 2017-01-19
- Published
- 2016-12-12
- Modified Date
- 2017-01-03
- Seq
- 2016-9938
