Recently, ESET and Sophos security researchers found out that hackers are trying to transfer an old backdoor Trojan from Linux to the latest Apple Mac OS X platform. By doing this the hackers are trying to expand their reach of PCs which they will be able to use for botnets.
Researchers revealed that the Trojan - Tsunami, gets connected to any IRC channel and then waits for the hackers commands. The commands might vary from instruction to flood any server with unlimited requests. This along with efforts of other computers which are compromised can lead to Distributed denial-of-service attack.
The Trojan also has the ability to download files to any computer which is compromised. This can update itself as well as upload additional malware and also gives complete control to the attacker who can command anything to the compromised computer.
For a while now, the C source code used in Linux variant has been available for the public. So anyone can change or modify this codes which will further affect multiple platforms.
But, the Trojan does not have any method for spreading. Thus, by exploiting a separate vulnerability to upload the malware secretly or by having hands-on access to a target system are only ways the malware can spread.