When the worm is executed, it creates the following mutex so that only one instance of the worm runs on the compromised computer:
It then sends one of the following messages, depending on the locale setting on the compromised computer, to all contacts in Skype and Windows Live Messenger:
hey é essa sua foto de perfil?
hej je to vasa nova slika profila?
hey c'est votre nouvelle photo de profil?
¿hey esta es tu nueva foto de perfil?
hey ini foto profil?
hei er dette din nye profil bilde?
hej to jest twój nowy obraz profil?
hey ito sa iyong larawan sa profile?
¿aquesta és la teva nova foto de perfil?
hej detta är din nya profilbild?
hej jeli ovo vasa nova profil skila?
hey là anh tieu cua ban?
sa k’vo profili lusankary
hey è la tua immagine del profilo nuovo?
tas ir jusu jauna profila bildes?
moin, kaum zu glauben was für schöne fotos von dir auf deinem profil
hei zhè shì ni de gèrén ziliào zhàopiàn ma?
hey bu yeni profil pic?
ni phaph porfil khxng khun?
hej er det din nye profil billede?
lol is this your new profile pic?
hoi schöni fotis hesch du uf dim profil öppe nöd?
hé ez az új profil kép?
on tämä uusi profiilikuva?
eínai aftí i néa fotografía profíl sas?
hej je to tvuj nov
hey is dit je nieuwe profielfoto?
tung, cka paske lyp ti nket fotografi?
The message also includes the following link:
[USER ID] is the Skype/Windows Live Messenger user ID.
At the time of writing, the link downloads either a copy of the worm or W32.IRCBot.NG.
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":
Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.