In a report titled "2005: *nix Malware Evolution," the Russian antivirus software developer pointed out that the number of Linux-based malicious programs -- viruses, Trojans, back-doors, exploits, and whatnot -- doubled from 422 to 863.
Numerically, that pales compared to the 11,000 Kaspersky found for Windows in the second half of 2005 alone.
However, it could be more devastating because many non-Windows users assume malware is only a Windows problem and don't take any precautions. Kaspersky said Linux users are careful, but one security expert disagrees.
"With Linux users, there's a very vigilant effort to make sure the system is as secure as possible, mostly because Linux people are very aware of security dangers and the security that needs to be put in place," said Shane Coursen, senior technical consultant with Kaspersky's U.S. office in Woburn, Mass.
"The other thing is that there are people who have transitioned from Windows to Linux, thinking Linux would provide them more security, and they make sure their new Linux system is secured," he added.