AST-2007-027 - Database matching order permits host-based authentication to be ignored

           Asterisk Project Security Advisory - AST-2007-027

±-----------------------------------------------------------------------+
| Product | Asterisk |
|--------------------±--------------------------------------------------|
| Summary | Database matching order permits host-based |
| | authentication to be ignored |
|--------------------±--------------------------------------------------|
| Nature of Advisory | Logic error |
|--------------------±--------------------------------------------------|
| Susceptibility | Remote Unauthenticated Sessions |
|--------------------±--------------------------------------------------|
| Severity | Moderate |
|--------------------±--------------------------------------------------|
| Exploits Known | No |
|--------------------±--------------------------------------------------|
| Reported On | October 30, 2007 |
|--------------------±--------------------------------------------------|
| Reported By | Tilghman Lesher <tlesher AT digium DOT com> |
|--------------------±--------------------------------------------------|
| Posted On | December 18, 2007 |
|--------------------±--------------------------------------------------|
| Last Updated On | December 18, 2007 |
|--------------------±--------------------------------------------------|
| Advisory Contact | Tilghman Lesher <tlesher AT digium DOT com> |
|--------------------±--------------------------------------------------|
| CVE Name | CVE-2007-6430 |
±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+
| Description | Due to the way database-based registrations ("realtime") |
| | are processed, IP addresses are not checked when the |
| | username is correct and there is no password. An |
| | attacker may impersonate any user using host-based |
| | authentication without a secret, simply by guessing the |
| | username of that user. This is limited in scope to |
| | administrators who have set up the registration database |
| | ("realtime") for authentication and are using only |
| | host-based authentication, not passwords. However, both |
| | the SIP and IAX protocols are affected. |
±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+
| Resolution | As a workaround, administrators may set a password for |
| | all users and peers in their registration "realtime" |
| | database. A fix is included in the newest release of |
| | Asterisk, as provided below. |
±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+
| Links | |
±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+
| Asterisk Project Security Advisories are posted at |
| http://www.asterisk.org/security |
| |
| This document may be superseded by later versions; if so, the latest |
| version will be posted at |
| http://downloads.digium.com/pub/security/AST-2007-027.pdf and |
| http://downloads.digium.com/pub/security/AST-2007-027.html |
±-----------------------------------------------------------------------+

±-----------------------------------------------------------------------+

           Asterisk Project Security Advisory - AST-2007-027
          Copyright (c) 2007 Digium, Inc. All Rights Reserved.

Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.