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securityvulnsSecurityvulnsSECURITYVULNS:DOC:21116
HistoryJan 09, 2009 - 12:00 a.m.

AST-2009-001: Information leak in IAX2 authentication

2009-01-0900:00:00
vulners.com
5
           Asterisk Project Security Advisory - AST-2009-001

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| Product | Asterisk |
|----------------------Âą------------------------------------------------|
| Summary | Information leak in IAX2 authentication |
|----------------------Âą------------------------------------------------|
| Nature of Advisory | Unauthorized data disclosure |
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| Susceptibility | Remote Unauthenticated Sessions |
|----------------------Âą------------------------------------------------|
| Severity | Minor |
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| Exploits Known | Yes |
|----------------------Âą------------------------------------------------|
| Reported On | October 15, 2008 |
|----------------------Âą------------------------------------------------|
| Reported By | http://www.unprotectedhex.com |
|----------------------Âą------------------------------------------------|
| Posted On | January 7, 2009 |
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| Last Updated On | January 7, 2009 |
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| Advisory Contact | Tilghman Lesher < tlesher AT digium DOT com > |
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| CVE Name | CVE-2009-0041 |
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| Description | IAX2 provides a different response during authentication |
| | when a user does not exist, as compared to when the |
| | password is merely wrong. This allows an attacker to |
| | scan a host to find specific users on which to |
| | concentrate password cracking attempts. |
| | |
| | The workaround involves sending back responses that are |
| | valid for that particular site. For example, if it were |
| | known that a site only uses RSA authentication, then |
| | sending back an MD5 authentication request would |
| | similarly identify the user as not existing. The |
| | opposite is also true. So the solution is always to send |
| | back an authentication response that corresponds to a |
| | known frequency with which real authentication responses |
| | are returned, when the user does not exist. This makes |
| | it very difficult for an attacker to guess whether a |
| | user exists or not, based upon this particular |
| | mechanism. |
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| Resolution | Upgrade to revision 167259 of the 1.2 branch or 167260 of |
| | the 1.4 branch or one of the releases noted below. |
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Affected Versions
Product
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Asterisk Open Source
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Asterisk Open Source
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Asterisk Open Source
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Asterisk Addons
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Asterisk Addons
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Asterisk Addons
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Asterisk Business Edition
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Asterisk Business Edition
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Asterisk Business Edition
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Asterisk Business Edition
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AsteriskNOW
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s800i (Asterisk Appliance)
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Corrected In
Product
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Asterisk Open Source
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Asterisk Open Source
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Asterisk Open Source
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Asterisk Business Edition
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Asterisk Business Edition
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Asterisk Business Edition
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s800i (Asterisk Appliance)
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Patches
URL
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http://downloads.digium.com/pub/security/AST-2009-001-1.2.diff
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http://downloads.digium.com/pub/security/AST-2009-001-1.4.diff
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http://downloads.digium.com/pub/security/AST-2009-001-1.6.0.diff
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| Links | http://code.google.com/p/iaxscan/ |
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| 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-2009-001.pdf and |
| http://downloads.digium.com/pub/security/AST-2009-001.html |
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Revision History
Date
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2009-01-07
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           Asterisk Project Security Advisory - AST-2009-001
          Copyright &#40;c&#41; 2009 Digium, Inc. All Rights Reserved.

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