Attackers long have used distributed denial-of-service (DDoS) attacks as cover for more nefarious hacking activity. But it turns out the recent high-profile DDoS and data destruction attacks on major South Korean banks, media outlets, and other entities were also a glaring example of such subterfuge, as cyberespionage actors posed as hacktivists knocking websites offline and wiping hard drives -- while in the background quietly stealing military secrets about South Korea and the U.S.
The so-called Dark Seoul DDoS and data annihilation attack on South Korean entities on March 20 has now been tied to earlier campaigns against South Korean targets, as well as the most recent attacks on June 25, according to new research by McAfee. The attacks are all part of a four-year effort to steal information about South Korean military and government operations that McAfee has dubbed Operation Troy, which also targeted U.S. Forces Korea, Republic of Korea, the Korean Department of Defense, and the U.S. Department of Defense, according to McAfee. "The attacks on South Korean targets were actually the conclusion of a covert espionage campaign," according to McAfee's report.
Waves of cyberattacks on South Korean banks and media networks at 2 p.m. local time on March 20 wiped the hard drives of tens of thousands of computers and defaced machines with a message from "The WhoIs Team." Network provider LG + U's website was defaced as well. Another group that went by the name NewRomanic Cyber Army Team via a pop-up Web message on some of the victim sites claimed to have in its possession personal data stolen from the victim organizations.
Most recently, South Korean universities were hit by massive malware infections. Aviv Raff, CTO at Seculert, said the malware used in the attacks -- PinkStats -- had been in use for more than four years, targeting various nation-states and organizations worldwide. While Raff didn't find any direct connection to the March 20 attacks, he noted that PinkStats was written by Chinese-speaking attackers, so the plot thickens on whether North Korea, China, or a combination thereof are the perpetrators of the attacks on South Korea.
Meanwhile, all of the loud and destructive hacking and claiming of responsibility posing as hacktivist activity was a ruse to hide old-fashioned cyberespionage. And the series of attacks against South Korea were all waged by one well-heeled and sophisticated entity, McAfee researchers say. "The main takeaway here is what we saw on June 25, March 20, and previous attacks [on South Korea] were not just isolated incidents: There was more to those than the destructive component and [disruption of website] availability," says Jim Walter, manager of the McAfee Threat Intelligence Service (MTIS) for the Office of the CTO. "These things are tied together."
Walter says the systems the attackers wiped already had been under their control for some time, thanks to the Operation Troy's botnet and sophisticated malware. "It took a certain amount of coordination for the [March destruction] on that number of machines," he says.
Symantec last month concluded the gang behind the DarkSeoul attacks had been in action for four years in attacks on South Korea, including the June 25 attacks -- the anniversary of the start of the Korean war -- the March attacks on banks and media outlets, and the May attacks on South Korean banks.
"Symantec expects the DarkSeoul attacks to continue and, regardless of whether the gang is working on behalf of North Korea or not, the attacks are both politically motivated and have the necessary financial support to continue acts of cybersabotage on organizations in South Korea ... the DarkSeoul gang is almost unique in its ability to carry out such high-profile and damaging attacks over several years," Symantec researchers said in a blog post last month. A Symantec spokesperson said the company at this time has no other information to share about the attacks beyond that research note.
[Spearphishing email discovered as a possible initial attack vector, malicious Android mobile clue found. See South Korea Attackers Set Time Bomb For Data-Destroying Malware.]
Malware used in the attacks is tied to code first created in 2009, and the attackers from the start were attempting to pilfer intelligence from South Korea military targets. The remote access Trojan employed in the attacks and the malware for wiping the Master Boot Record (MBR) of the targeted computers were both compiled in late January, according to McAfee's findings. And victim zero was infected via a spearphishing attack prior to March 20.
The Trojan dropper was compiled just a few hours before the March attack, wiping the MBRs within minutes after it was unleashed.
The attackers also used an encrypted network and automated reconnaissance tools to sniff out "specific military information" on the victims' networks, according to McAfee's findings.
Darin Dutcher, cyberthreat researcher with Trend Micro, says the correlation of similar tools across the various attacks is interesting. "The correlation of similar tools across differing attacks over time are notable. Whether this is due to a concerted campaign by a single threat actor posing as multiple groups against a target or multiple threat actors using similar tools can be difficult to prove," Dutcher says.
McAfee's Walter won't conclude the attacks are nation-state-sponsored, but the characteristic earmarks of such an entity are there: "The level of sophistication alone, and the tools and tactics they utilized" rule out hacktivists, he says. The malware's time of compilation, distribution, and execution was well-coordinated and the work of a sophisticated group, he says.
"And their complex use of encryption through HTTP and IRC channels ... it's a level well above what we typically see from an everyday hacktivist group," he says.
So why destroy the victims' data? "It's similar to what we saw in Shamoon. Once the compromise was discovered, and [people] started tracking it back ... that's when those machines were wiped," he says. "It can be a similar situation on 3/20: Some people were starting to get [alerted] to what was going on, or a piece of the puzzle was discovered, and the safest [thing for the attackers] was to wipe the machines and get out," he says.
The data-destruction phase can signify the end of an attack campaign if the mission has been met, for instance, notes Trend Micro's Dutcher. "But it can also mean that those were the calculated and expendable exploited resources for that point in time, meaning that more actions can be expected be expected in the future," he says.
Researchers haven't closed the book on the cyberespionage campaign just yet. "Some of this is still unfolding," Walter says. "Some pieces may become more clear as we continue down this path, such as why the [South Korean] media components were so interesting" to the attackers, he says.
The full report by McAfee on Operation Troy is available here (PDF) for download.
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