CVE-2016-9938
Severity CVSS v4.0:
Pending analysis
Type:
CWE-285
Improper Authorization
Publication date:
12/12/2016
Last modified:
12/04/2025
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. 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.
Impact
Base Score 3.x
5.30
Severity 3.x
MEDIUM
Base Score 2.0
5.00
Severity 2.0
MEDIUM
Vulnerable products and versions
| CPE | From | Up to |
|---|---|---|
| cpe:2.3:a:digium:asterisk:11.0.0:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.0.0:beta1:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.0.0:beta2:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.0.0:rc1:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.0.0:rc2:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.0.1:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.0.2:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.1.0:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.1.0:rc1:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.1.0:rc3:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.1.1:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.1.2:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.2.0:*:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.2.0:rc1:*:*:*:*:*:* | ||
| cpe:2.3:a:digium:asterisk:11.2.0:rc2:*:*:*:*:*:* |
To consult the complete list of CPE names with products and versions, see this page