I've seen this kinda of thing before - although it relied upoon the user to download a file in order to spread.

it was something like

ROFL you gotta see this
Accept File Pic123.jpg.exe
once installed it didn't do anything malicous just started PM'ing everyone on your list with a request to accept the file - I wrote a simple bat/reg file to clean up infected machines I got so annoyed at all my friends PM'ing me with requests >_<;

ICQ had one as well but the file attachment was called something like

FunnyNude.jpg .exe

all the spaces would mean that ICQ wouldn't show the real exstension as it had a limit on characters shown and didn't trunchicate the name so that it became something like FunnyNude.jpg....exe - instead it just cut the last part of the name hiding the real payload

dunno if that has been fixed yet - never use ICQ anymore

v_Ln