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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2011.0056.2 Asterisk Project Security Advisory - AST-2011-001 21 January 2011 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Asterisk Open Source Asterisk Business Edition AsteriskNOW s800i (Asterisk Appliance) Publisher: Digium Operating System: UNIX variants (UNIX, Linux, OSX) Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2011-0495 Original Bulletin: http://downloads.digium.com/pub/security/AST-2011-001.html Revision History: January 21 2011: Added CVE Name and Changed 1.8.2.1 to 1.8.2.2 for fix versions January 19 2011: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Asterisk Project Security Advisory - AST-2011-001 Product Asterisk Summary Stack buffer overflow in SIP channel driver Nature of Advisory Exploitable Stack Buffer Overflow Susceptibility Remote Authenticated Sessions Severity Moderate Exploits Known No Reported On January 11, 2011 Reported By Matthew Nicholson Posted On January 18, 2011 Last Updated On January 20, 2011 Advisory Contact Matthew Nicholson <mnicholson@digium.com> CVE Name CVE-2011-0495 Description When forming an outgoing SIP request while in pedantic mode, a stack buffer can be made to overflow if supplied with carefully crafted caller ID information. This vulnerability also affects the URIENCODE dialplan function and in some versions of asterisk, the AGI dialplan application as well. The ast_uri_encode function does not properly respect the size of its output buffer and can write past the end of it when encoding URIs. Resolution The size of the output buffer passed to the ast_uri_encode function is now properly respected. In asterisk versions not containing the fix for this issue, limiting strings originating from remote sources that will be URI encoded to a length of 40 characters will protect against this vulnerability. exten => s,1,Set(CALLERID(num)=${CALLERID(num):0:40}) exten => s,n,Set(CALLERID(name)=${CALLERID(name):0:40}) exten => s,n,Dial(SIP/channel) The CALLERID(num) and CALLERID(name) channel values, and any strings passed to the URIENCODE dialplan function should be limited in this manner. Affected Versions Product Release Series Asterisk Open Source 1.2.x All versions Asterisk Open Source 1.4.x All versions Asterisk Open Source 1.6.x All versions Asterisk Open Source 1.8.x All versions Asterisk Business Edition C.x.x All versions AsteriskNOW 1.5 All versions s800i (Asterisk Appliance) 1.2.x All versions Corrected In Product Release Asterisk Open Source 1.4.38.1, 1.4.39.1, 1.6.1.21, 1.6.2.15.1, 1.6.2.16.1, 1.8.1.2, 1.8.2.2 Asterisk Business Edition C.3.6.2 Patches URL Branch http://downloads.asterisk.org/pub/security/AST-2011-001-1.4.diff 1.4 http://downloads.asterisk.org/pub/security/AST-2011-001-1.6.1.diff 1.6.1 http://downloads.asterisk.org/pub/security/AST-2011-001-1.6.2.diff 1.6.2 http://downloads.asterisk.org/pub/security/AST-2011-001-1.8.diff 1.8 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-2011-001.pdf and http://downloads.digium.com/pub/security/AST-2011-001.html Revision History Date Editor Revisions Made 2011-01-18 Matthew Nicholson Initial Release 2011-01-19 Matthew Nicholson Added CVE Name 2011-01-20 Matthew Nicholson Changed 1.8.2.1 to 1.8.2.2 for fix versions Asterisk Project Security Advisory - AST-2011-001 Copyright (c) 2011 Digium, Inc. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iD8DBQFNOPSK/iFOrG6YcBERAstvAKCY3M8yQl7Ey37l4TjCB6A3pY5pWQCgka8i qy2JBUiWdanQuS67M5qV248= =utIj -----END PGP SIGNATURE-----