Podatność CVE-2016-9938


Publikacja: 2016-12-12   Modyfikacja: 2016-12-13

Opis:
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.

CVSS2 => (AV:N/AC:L/Au:N/C:N/I:P/A:N)

Ogólna skala CVSS
Znaczenie
Łatwość wykorzystania
5/10
2.9/10
10/10
Wymagany dostęp
Złożoność ataku
Autoryzacja
Zdalny
Niska
Nie wymagana
Wpływ na poufność
Wpływ na integralność
Wpływ na dostępność
Brak
Częściowy
Brak
Affected software
Digium -> Asterisk 
Digium -> Certified asterisk 
Asterisk -> Open source 

 Referencje:
http://downloads.asterisk.org/pub/security/AST-2016-009.html
http://www.securityfocus.com/bid/94789
http://www.securitytracker.com/id/1037408

Copyright 2022, cxsecurity.com

 

Back to Top