Voice over IP (VoIP) systems are gaining in popularity as the technology for transmitting voice traffic over IP networks. As the popularity of VoIP systems increases, they are being subjected to different kinds of intrusions some of which are specific to such systems and some which follow a general pattern of IP attacks. VoIP systems pose several new challenges to Intrusion Detection System (IDS) designers. First, these systems employ multiple protocols for call management (e.g., SIP) and data delivery (e.g., RTP). Second, the systems are distributed in nature and employ distributed clients, servers and proxies. Third, the attacks to such systems span a large class, from denial of service to billing fraud attacks. Finally, the systems are heterogeneous, have soft real time requirements, and are typically under several different administrative domains. In this paper, we propose the design of an intrusion detection system targeted to VoIP systems, called SPACEDIVE. SPACEDIVE is structured to detect different classes of intrusions, including, masquerading, denial of service, and media stream-based attacks. It can be installed at multiple points

On the evening of 2 November 1988, someone infected the Internet with a worm program. That program exploited flaws in utility programs based on BSD-derived versions of UNIX. The flaws allowed the program to break into those machhines and copy itself, thus infecting those systems. Thi sprogram eventually spread to thousands of machines , and disrupted normal activities and Internet connectivity for many days. This report gives a detailed description of the components of the worm program-data and functions. It is based on a study of two completely independent reverse-compilations of the worm and a version disassembled to VAX assembly language. Almost no source code is given in the paper because of current concerns about the state of the “immune system” of Internet hosts, but the description should be detailed enough to allow the reader to understand the behavior of the program.  The paper contains a review of the securty flaws exploited by the worm program, and gives some recommendations on how to eliminate or mitigate their future use. The report also includes and analysis of the coding style and methods used by the author(s) of the worm , and draw some conclusions about his abilities and intent.