The 4th Workshop on Recurring Malcode (WORM), 2006. Internet-wide infectious epidemics have emerged as one of the leading threats to information security and service availability. Self- propagating threats, generally termed 'worms', exploit software weaknesses, hardware limitations, Internet topology, and the open Internet communication model to compromise large numbers of networked systems. Internet worms are increasingly being used as delivery mechanisms for malicious payloads such as spyware, phishing servers, spam relays, and information espionage. Unfortunately, current operational practices still face significant challenges in containing these threats as evidenced by the rise in automated botnet networks and the continued presence of worms released years ago. This workshop provides a forum for exchanging ideas, increasing understanding, and relating experiences on self-propagating malicious software from a wide range of communities, including academia, industry, and the government. We are soliciting papers from researchers and practitioners on subjects including, but not limited to: Automatic worm detection and characterization Reactive countermeasures Proactive defenses Detecting and disrupting botnets and malware command and control Threat assessment New threats and related challenges Measurement studies Testbeds \amp; evaluation Reverse engineering Significant operational experiences Analysis of worm/botnet construction, current \amp; future Modeling and analysis of propagation dynamics Forensic methods of attribution WORM aims to be a true workshop, with a primary goal of fostering the development of preliminary work and helping nucleate a worm-research community. To this end, WORM is open to two classes of submissions. Paper Submissions: First and foremost, we invite traditional paper submissions describing original work to appear in the WORM Proceedings to be published by ACM. Such submissions must not have been previously published and must not be in simultaneous submission elsewhere. Papers describing original work should be at most 8 pages long (double column) in an 11-point font with at least 1-inch margins. Significantly shorter papers will also be considered in terms of the degree to which they might contribute to the Workshop goals of fostering a worm-research community. All such accepted papers will appear in the ACM WORM Proceedings. Papers submitted must be original unpublished work and must not be simultaneously submitted or under review for any other workshop, conference or journal. Any paper found to be in violation of these rules will be rejected without review. Papers accompanied by non- disclosure agreement forms will not be considered. All submissions are treated as confidential, both as a matter of policy and in accordance with the U.S. Copyright Act of 1976. Panel Submissions: WORM is also soliciting proposals for a discussion panel on a topic relevant to the workshop. Panel proposals must include the title of the panel, an abstract describing the topic and why it should be of interest to the WORM community, and a list of potential panelists. Panels are expected to be at most 1 hour long, comprised of short presentations by the panelists followed by discussion among panel members and the audience; other formats may be used, but should be described in the proposal. Submission Instructions: Papers must be received by 23:59:59 (EDT) of June 16th, 2006. Reviews of submissions and notification of acceptance or rejection will be sent to the authors no later than August 9th, 2006, and, for papers to appear in the WORM Proceedings, authors will have an opportunity to revise their work by August 21st, 2006. PLEASE NOTE: Authors of accepted papers must guarantee that their paper will be presented at the workshop. More detailed submission instructions will be posted in a timely manner on this page. Important Dates: Paper submissions due: June 16th, 2006 Acceptance notifications: August 9th, 2006 Camera ready copy for accepted papers: August 21st, 2006 CCS Conference: October 30th - November 3rd, 2006 The workshop will be held on November 3rd, 2006. Please see http://www.eecs.umich.edu/~farnam/worm2006.html for more details.