A mysterious group of computer hackers has spent four years spying on the South Korea military, US security software maker McAfee has said, citing evidence uncovered from malicious software samples.
The findings, which were not confirmed by authorities in Seoul, provide one possible motive for ongoing attacks on South Korea that date to 2009.
McAfee, a division of Intel Corp, did not identify a sponsor for the attacks but said they were carried out by a hackers group known as the New Romanic Cyber Army Team. Seoul has blamed North Korea for some of the cyber attacks although Pyongyang denies responsibility and says it too has been a victim.
Officials at the South Korean Embassy in Washington were not immediately available for comment. A Pentagon spokesman said he was unaware of McAfee's findings and declined comment.
Experts with Symantec, another security software maker, last month definitively linked the four-year string of attacks to a single group of hackers. The attacks hit government and corporate computers.
McAfee released a 29-page technical paper on Monday that analysed the code of the software used by those hackers, whose identity is still not known.
It said the hacking gang infected PCs with sophisticated software that automatically sought out documents of interest by scanning computers for military keywords in English and Korean.
Once the software identified documents of interest, it encrypted those files then delivered them to the hackers' servers, McAfee said.
The paper also described in detail how the attackers siphoned data from infected computers using a sophisticated infrastructure known as a "botnet."
McAfee named the attacks "Operation Troy," because the word Troy frequently appeared in the code of the malicious software. The New Romanic Cyber Army Team makes frequent use of Roman and classical terms in their code.
On July 4, 2009, it launched its first significant attack, unleashing malicious software that wiped data on PCs and also disrupted some government and business websites in South Korea and the United States.
In March, the gang knocked tens of thousands of PCs off line at South Korean companies by destroying data on their hard drives. It was one of the most destructive cyber attacks on private computer networks to date.
McAfee published its report on the gang on its website: