Abstract: Methods and systems for reducing the spread of malware in communication between an instant message (IM) client and an IM server are described. An IM filter module (IM FM) is configured to examine incoming messages from an IM server to an IM client and outgoing messages from the IM client to the IM server. The IM filter module is further configured to analyze relationship among the incoming and outgoing messages and determine whether one or more messages contain malware based on the analysis of relationship among the incoming and outgoing messages.

Abstract: Methods and systems for reducing the spread of malware in communication between an instant message (IM) client and an IM server are described. A malware trapping system (MTS) creates and registers a set of virtual IM users with an IM server. The virtual IM users include account names by which other users of the IM server can communicate with the virtual IM users. The MTS publicizes the account names of the virtual IM users, which causes sources of malware to illicitly acquire the account names of the virtual IM users. The MTS identifies any IM user sending a message to one of the virtual users as a source of malware. The MTS also identifies such a message as a malware message and collects information about the sources of malware and malware messages and stores the information in a database. An IM filter module, accessing the information stored in the database, identifies and blocks malware messages based on the information.

Abstract: Methods and systems for reducing the spread of malware in communication between an instant message (IM) client and an IM server are described. An IM filter module (IM FM) is configured to intercept a buddy list sent from an IM server to an IM client, add one or more fictitious buddies to the intercepted buddy list, and forward the buddy list with the one or more fictitious buddies to the IM client. The IM FM is further configured to identify a computer that hosts the IM client as a source of malware based on messages sent by the IM client to at least one of the fictitious buddies and to determine that the host computer of the IM client is a source of malware if a content of the messages sent to the at least one of the fictitious buddies contains malware.

Abstract: Methods and systems for reducing the spread of malware in communication between an instant message (IM) client and an IM server are described. An IM filter module (IM FM) is configured to analyze messages exchanged between an IM server and an IM client. The IM FM also identifies one or more messages as possibly containing malware among the exchanged messages and assigns a confidence level to each identified message. A confidence level represents a probability of a message containing malware. A Bayesian filter is configured to train itself using the identified messages and the confidence levels and adjust the confidence levels. A feedback training mechanism for the Bayesian filter is also included. In particular, the IM FM examines additional messages exchanged between the IM server and IM client, identifies one or more messages as possibly containing malware among the additional messages using the adjusted confidence values. The IM FM also assigns a confidence level to each additionally identified message.