CVE-2016-9938 Detail
Modified
This vulnerability has been modified since it was last analyzed by the NVD. It is awaiting reanalysis which may result in further changes to the information provided.
Current 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.
Source:
MITRE
Description Last Modified:
12/12/2016
View Analysis Description
Analysis 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.
Source:
MITRE
Description Last Modified:
12/12/2016
Impact
CVSS v3.0 Severity and Metrics:
Base Score:
5.3 MEDIUM
Vector:
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
(V3 legend)
Impact Score:
1.4
Exploitability Score:
3.9
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
Low
Availability (A):
None
CVSS v2.0 Severity and Metrics:
Base Score:
5.0 MEDIUM
Vector:
(AV:N/AC:L/Au:N/C:N/I:P/A:N)
(V2 legend)
Impact Subscore:
2.9
Exploitability Subscore:
10.0
Access Vector (AV):
Network
Access Complexity (AC):
Insufficient_Info
Authentication (AU):
None
Confidentiality (C):
None
Integrity (I):
Partial
Availability (A):
None
Additional Information:
Allows unauthorized modification
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Change History
4 change records found
- show changes
CVE Modified by MITRE -
7/26/2017 9:29:07 PM
| Action |
Type |
Old Value |
New Value |
| Added |
Reference |
|
http://www.securitytracker.com/id/1037408 [No Types Assigned] |
Reanalysis -
1/3/2017 2:58:44 PM
| Action |
Type |
Old Value |
New Value |
| Added |
CPE Configuration |
|
Record truncated, showing 500 of 2892 characters.
View Entire Change Record
OR
*cpe:2.3:a:digium:certified_asterisk:11.0.0:*:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.0.0:rc1:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.0.0:rc2:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.1.0:*:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.1.0:rc1:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.1.0:rc2:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.1.0:rc3:*:*:*:*:*:*
*cpe:2.3:a:digium:certified_asterisk:11.2 |
| Changed |
CPE Configuration |
Record truncated, showing 500 of 6009 characters.
View Entire Change Record
OR
*cpe:2.3:a:asterisk:open_source:11.0.0:*:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:beta1:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:beta2:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:rc1:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:rc2:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.1:*:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.2:*:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.1.0:*:*:*:*:*:*:*
*cpe:2.3:a:aster |
Record truncated, showing 500 of 5499 characters.
View Entire Change Record
OR
*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:*:*:*:*:*:*
* |
Initial Analysis -
12/22/2016 11:20:32 AM
| Action |
Type |
Old Value |
New Value |
| Added |
CPE Configuration |
|
Record truncated, showing 500 of 6009 characters.
View Entire Change Record
OR
*cpe:2.3:a:asterisk:open_source:11.0.0:*:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:beta1:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:beta2:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:rc1:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.0:rc2:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.1:*:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.0.2:*:*:*:*:*:*:*
*cpe:2.3:a:asterisk:open_source:11.1.0:*:*:*:*:*:*:*
*cpe:2.3:a:aster |
| Added |
CVSS V2 |
|
(AV:N/AC:L/Au:N/C:N/I:P/A:N) |
| Added |
CVSS V3 |
|
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| Added |
CWE |
|
CWE-285 |
| Changed |
Reference Type |
http://downloads.asterisk.org/pub/security/AST-2016-009.html No Types Assigned |
http://downloads.asterisk.org/pub/security/AST-2016-009.html Mitigation, Vendor Advisory |
| Changed |
Reference Type |
http://www.securityfocus.com/bid/94789 No Types Assigned |
http://www.securityfocus.com/bid/94789 Third Party Advisory, VDB Entry |
CVE Modified by MITRE -
12/15/2016 9:59:09 PM
| Action |
Type |
Old Value |
New Value |
| Added |
Reference |
|
http://www.securityfocus.com/bid/94789 [No Types Assigned] |
Quick Info
CVE Dictionary Entry:
CVE-2016-9938
NVD Published Date:
12/12/2016
NVD Last Modified:
07/26/2017
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