Hat-Squad Advisory: Remote Heap Corruption Vulnerability in Interaction SIP Proxy Product: Interaction SIP Proxy Vendor: Interactive Intelligence Inc. (http://www.inin.com) Systems Affected: Vonexus Enterprise Interaction Center Interaction SipProxy 3.0.010 Release Date: 12/21/2005 Vendor Status: Informed on 12/11/2005 Initial response on 12/12/2005 Patch released on 12/18/2005 Overview: Interaction SIP Proxy is Microsoft Windows-based software that provides basic SIP proxy and registrar functionality as defined in the IETF SIP-oriented RFC 3261. The Interaction SIP Proxy routes incoming SIP messages based on configurable dial plan and server plans, with simplified administration via Web interface. Problem: Hat-Squad security team has discovered a remote heap overflow in Interaction SIP Proxy. The vulnerability allows a remote attacker to overwrite heap memory and cause a a severe denial-of-service condition on system. Exploitation of this vulnerability for code execution requires a magic sequence of pre-allocations, data and size. Technical Details: The code in i3sipmsg.dll is responsible for handling SIP requests. The vulnerability is triggered by sending 2900 bytes of space (0x20) or TAB (0x9) characters as SIP version in a REGISTER request line. This will cause a heap overflow in SIPParser function. A Proof of concept for this vulnerability is available at http://www.hat-squad.com/i3sip.html Credits: This Vulnerability has been Discovered By Behrang Fouladi (behrang hat-squad com) Greetings: Persia, Hamid, Hesam geek, Nima, Brett Moore, class101 and Babak