
Recently, experts noted that two types of malware - Spy Eye and Zeus - were recorded 'fighting' each other for control of computers, with Spy Eye including coding to destroy the other trojan.
Both pieces of malware are designed to steal banking information from computers, with Spy Eye selling for around £320 to cybercriminals - less than a fifth of the price of Zeus.
Commenting on the malware-on-malware attack, SophosLabs manager Richard Wang claimed it demonstrates the lengths hackers will go to increase their earnings from trojans.
'Using one form of malware to attack another is a means of increasing market share and thereby the value of a botnet or other set of controlled computers,' he said.
The expert also predicted that such attacks could become more common, as the number of viruses increase their competition to dominate the declining numbers of computers which remain uninfected.

Both pieces of malware are designed to steal banking information from computers, with Spy Eye selling for around £320 to cybercriminals - less than a fifth of the price of Zeus.
Commenting on the malware-on-malware attack, SophosLabs manager Richard Wang claimed it demonstrates the lengths hackers will go to increase their earnings from trojans.
'Using one form of malware to attack another is a means of increasing market share and thereby the value of a botnet or other set of controlled computers,' he said.
The expert also predicted that such attacks could become more common, as the number of viruses increase their competition to dominate the declining numbers of computers which remain uninfected.
