Vulnerability identifier: #VU12322

Vulnerability risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2009-0041

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Description
IAX2 in Asterisk Open Source 1.2.x before 1.2.31, 1.4.x before 1.4.23-rc4, and 1.6.x before 1.6.0.3-rc2; Business Edition A.x.x, B.x.x before B.2.5.7, C.1.x.x before C.1.10.4, and C.2.x.x before C.2.1.2.1; and s800i 1.2.x before 1.3.0 responds differently to a failed login attempt depending on whether the user account exists, which allows remote attackers to enumerate valid usernames.

Mitigation
Install update from vendor's website.

External links
http://www.securityfocus.com/bid/33174
http://www.vupen.com/english/advisories/2009/0063
http://www.securitytracker.com/id?1021549
http://www.securityfocus.com/archive/1/archive/1/499884/100/0/threaded
http://www.debian.org/security/2009/dsa-1952
http://securityreason.com/securityalert/4910
http://security.gentoo.org/glsa/glsa-200905-01.xml
http://downloads.digium.com/pub/security/AST-2009-001.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.