North Korea prime suspect after crude Trojan aimed at South Korean think tanks

Kimsuky origins painted in neon

Kaspersky Lab has uncovered what looks like a surprisingly clunking attempt by North Korean hackers to steal data from think-tanks in hated neighbour South Korea using a poorly-concealed Trojan.

The Russian firm's analysis makes clear that attribution for 'Kimsuky' can't be planted on the door of North Korea with absolute certainty but it's hard to see why anyone else would be so interested in its target list.

These include among 11 South Korean organisations, the Sejong Institute, the Korea Institute For Defense Analyses (KIDA), the Ministry of Unification Government department, and Hyundai Merchant Marine, all attacked most likely using some form of spear phishing.

The malware first turns off the Windows firewall and the Windows service that alerts users to this event and, if it is present, tries to disable firewall software from South Korean firm AhnLab, an antivirus client extremely popular with businesses in the country.

Once achieved, it is able to attempt to send data gathered using sometimes poorly-implemented keylogging routines.

Another module is designed to steal documents created in the word processor that comes as part of the popular South Korean Hancom Office suite. An extremely unusual feature of this particular element of the malware is that it only notices these HWP files after they have been opened, ignoring those that lie on the system unread.

To make this work, the malware has to open the document itself before passing it to the real program. This is, presumably, a way of working out which documents are important rather than the attackers having to sift through a huge number.

Bizarrely, the hackers communicate with their creation using a Bulgarian email account registered to 'Kimsukyang' (hence the Trojan's moniker) and 'asdfa' rather than via a more conventional command and control. Are these the names of the attackers? Kaspersky Lab suspects so.

"The attackers' IP-addresses do provide some additional clues. During our analysis, we observed ten IP-addresses used by the Kimsuky operators. All of them lie in ranges of the Jilin Province Network and Liaoning Province Network, in China," said Kaspersky researcher, Dmitry Tarakanov.

"Interestingly, the ISPs providing internet access in these provinces are also believed to maintain lines into North Korea."

Kimsuky looks like a hasty attempt to plunder its South Korean targets which isn't to say that it was successful in its aim after its first appearance in April.

Not that long ago, attacks on a sector as obscure as think tanks in a country like South Korea would have been seen as interesting only to admins inside that country's borders. But cybercrime is a patchwork of sometimes influential campaigns and the likely culprit, North Korea, is being watched extremely closely.

South Korea has been hit by waves of attacks blamed on the North, most prominently a large-scale attack on 20 March against a large number of firms in the media sector. The attacks have subsided since then large because South Korean firms have tightened security, but June still saw a nasty disk-wiping assault pinned on the 'DarkSeoul' gang.

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