Asterisk Open Source 1.2.x before 1.2.26 and 1.4.x before 1.4.16, and Business Edition B.x.x before B.2.3.6 and C.x.x before C.1.0-beta8, when using database-based registrations ("realtime") and host-based authentication, does not check the IP address when the username is correct and there is no password, which allows remote attackers to bypass authentication using a valid username.

References

• https://nvd.nist.gov/vuln/detail/CVE-2007-6430
• https://exchange.xforce.ibmcloud.com/vulnerabilities/39124
• http://downloads.digium.com/pub/security/AST-2007-027.html
• http://lists.opensuse.org/opensuse-security-announce/2008-03/msg00001.html
• http://secunia.com/advisories/28149
• http://secunia.com/advisories/29242
• http://secunia.com/advisories/29456
• http://secunia.com/advisories/29782
• http://security.gentoo.org/glsa/glsa-200804-13.xml
• http://securityreason.com/securityalert/3467
• http://www.debian.org/security/2008/dsa-1525
• http://www.osvdb.org/39519
• http://www.securityfocus.com/archive/1/485287/100/0/threaded
• http://www.securityfocus.com/bid/26928
• http://www.securitytracker.com/id?1019110
• http://www.vupen.com/english/advisories/2007/4260