Moscow-based security firm Kaspersky Lab has detected 35 unique malicious programs that targeted the Bitcoin system.

As of late August, Kaspersky Lab’s analysts found that cybercriminals, realising that their potential earnings largely depend on the number of computers they have access to, have moved from stealing Bitcoin wallets to using Twitter and P2P network-based botnets.

Kaspersky said that the move was intended to counter action by the antivirus companies to block the operation of a single botnet command centre (C&C) server if no alternate servers exist in the malicious network.

The use of Twitter as a botnet C&C is the first time it has been used with the Bitcoin system, claimed Kaspersky.

The company added that excluding the J2ME platform, 85% of the total number of smartphone threats detected during August 2010 targeted the Android system.

The company also said that in August, it discovered that one of the largest botnets conceals actual accounts as they can be deleted by server owners who take a proactive stance against unlawful mining programs.

Kaspersky said that almost a year after the original code of the most wide-spread threat targeting online banking users was leaked, Trojan ZeuS (Trojan-Spy.Win32.Zbot), "Russian-speaking" cybercriminals created its clone which became popular among fraudsters this summer.

The new variant which emerged in the spring was dubbed Ice IX by its creator and sells for US $600-1,800, said the company.

The company added that the new network worm Morto is interesting in that it does not exploit vulnerabilities in order to self-replicate.

Kaspersky said that it detected the first-ever malicious program for the Android operating system in early August 2010: the SMS Trojan FakePlayer.