Virus-like program that spreads automatically to other computers by sending itself out by email or by any other means. A program that propagates itself by attacking other machines and copying itself to the affected machine.
Worms have self-replicating code that travels from machine to machine by various means. A worms first objective is merely propagation. Worms can be destructive depending on what payload they have been given. Worms may replace files, but do not insert themselves into files.
Comment:
W32.MSNmaker is a worm that spreads through MSN Messenger. This worm arrives as a file manually sent by a malicious user via MSN Messenger.
When executed, this worm rename the original file as msrr.exe and replaces the original MSN Messenger executable file msnmsgr.exe with a copy of itself. When the worm is executed, it also executes msrr.exe to avoid immediate detection.
Screenshots:
A typical snapshot showing the chat message containing malicious link sent by MSNMaker.
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