Asterisk IAX2 Protocol ACK response denial of service
| asterisk-iax2protocol-ack-dos (41966) |  Low Risk |
Description:
Asterisk is vulnerable to a denial of service, caused by the failure to verify the ACK response has a call number matching the server's reply to a NEW message during IAX2 handshakes by the IAX2 Protocol. By sending a spoofed ACK response message, a remote attacker could cause the system to release early audio packets to the targeted address and cause a denial of service.
Platforms Affected:
- Debian, Debian Linux 4.0
- Digium, Asterisk Business Edition B.2.5.1
- Digium, Asterisk Business Edition C.1.8
- Digium, Asterisk Open Source 1.2.27
- Digium, Asterisk Open Source 1.4.19
- Digium, AsteriskNOW 1.0.2
- Digium, s800i 1.1.0.2
- Gentoo, Linux
Remedy:
Refer to AST-2008-006 for patch, upgrade or suggested workaround information. See References.
Consequences:
Denial of Service
References:
- AltSci Concepts Web site, AltSci Concepts IAX2 Exploit Framework at https://www.altsci.com/concepts/page.php?s=asteri&p=2.
- AST-2008-006, 3-way handshake in IAX2 incomplete at http://downloads.digium.com/pub/security/AST-2008-006.html.
- Digium Issue Tracker ID 0010078, IAX2 protocol flaw in IC_NEW could cause reflective amplification DoS at http://bugs.digium.com/view.php?id=10078.
- BID-28901: Asterisk IAX2 Packet Amplification Remote Denial of Service Vulnerability
- CVE-2008-1897: The IAX2 channel driver (chan_iax2) in Asterisk Open Source 1.0.x, 1.2.x before 1.2.28, and 1.4.x before 1.4.19.1; Business Edition A.x.x, B.x.x before B.2.5.2, and C.x.x before C.1.8.1; AsteriskNOW before 1.0.3; Appliance Developer Kit 0.x.x; and s800i before 1.1.0.3, when configured to allow unauthenticated calls, does not verify that an ACK response contains a call number matching the server's reply to a NEW message, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed ACK response that does not complete a 3-way handshake. NOTE: this issue exists because of an incomplete fix for CVE-2008-1923.
- DSA-1563: asterisk -- denial of service
- GLSA-200905-01: Asterisk: Multiple vulnerabilities
- SA29927: Asterisk IAX2 Handshake Denial of Service
- SECTRACK ID: 1019918: Asterisk IAX2 Protocol Verification Bug Lets Remote Users Deny Service
- VUPEN/ADV-2008-1324: Asterisk IAX2 Protocol Verification Remote Denial of Service Vulnerability
Reported:
Apr 22, 2008
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