[Bert John]

http://forums.steampowered.com/forums/showthread.php?p=35468592
http://facepunch.com/showthread.php?t=1386818
Mainly hundred's of garrys mod server's are spreading around a virus that makes the client spam *cough* through ingame & steam itself.

EDIT: The client gets infected with this file, then when they leave, they join a new server and upload it there, and basically it just spams everywhere... infected servers have 3 ! infront of there names

Luckily it seems if you just turn sv_allowdownload and sv_allowupload to 0 and take the rcon pass out of server.cfg it should be fine
[Looks like a garrys mod only issue, so css should be fine?]

EDIT2: New version of virus released, deleting peoples files... id highly recommend staying off server's you know that arn't protected yet[Many server's are applying the patch, but theres still a bit that haven't]

EDIT3: Trojan's! http://facepunch.com/showthread.php?t=1351764

EDIT4: It's now changing player's names and such

EDIT5: There's a fix here: http://facepunch.com/showthread.php?t=1386855

Remember, this is ONLY GARRYS MOD, Not CSS

All fixed, All good, http://steamcommunity.com/games/garrysmod/announcements/detail/1498880232135333176

Note: Id recommend everyone who experianced this to reinstall garrys mod, as there was a trojan and another virus that stole credit cards