Dal 2007 la polizia tedesca usa un trojan chiamato Quellen-TKÜ per intercettare le chiamate via Skype (normalmente crittografate e dunque ‘sicure’). Un gruppo di hacker che ha fatto il reverse engineering del codice di Quellen ha scoperto che c’è molto di più:

European ‘hacker club’, the Chaos Computer Club, has claimed to have reverse engineered a sample of German authorities’ lawful intercept malware, Quellen-TKÜ, and found that besides eavesdropping on Skype conversations it also captures screenshots and logs keystrokes.

Il trojan contiene codice che permette l’esecuzione di comandi a distanza, attiva microfoni e webcam, memorizza i comandi dati da tastiera, può inviarli a server remoti e molto altro:

The CCC’s analysis showed the trojan was built from the outset to receive uploads from the web, contains remote execution capabilities and could be used to activate attached devices such as the computer’s microphone and camera for wider surveillance than just spying on telecommunications e, secondo Sophos, can log keystrokes in Firefox, Opera, Internet Explorer and SeaMonkey, take JPEG screenshots and record Skype audio calls. It labeled the trojan Troj/BckR2D2-A.