An analysis of hacker attacks on online servers in January by UK-based security consultancy mi2g found that Linux servers were the most frequently hit, accounting for 13,654 successful attacks, or 80 percent of the survey total. Windows came in a distant second with 2,005 attacks.
A detailed analysis of government servers also found Linux to be more susceptible, accounting for 57 percent of all security breaches.
In a similar study last year, Microsoft Windows proved to be more vulnerable, accounting for 51 percent of successful attacks on government servers.
However, the sharp rise in Linux breaches probably reflects a lack of training and deployment expertise rather than inherent security problems within Linux, mi2g officials suggested.
"The swift adoption of Linux last year within the online government and non-government server community, coupled with inadequate training and knowledge on how to keep that environment secure when running vulnerable third party applications, has contributed to a consistently higher proportion of compromised Linux servers," mi2g chairman DK Matai said in a statement.
According to the study, the most secure OS turned out to be BSD (Berkley Software Distribution) and Mac OS X.
mi2g said its study focused on "overt digital attacks" and did not include other methods of intrusion such as viruses and worms.