A malware program with data wiping functionality that was recently used to attack Sony Pictures Entertainment bears technical similarities to destructive malware that affected organizations in South Korea and the Middle East in the past.
Security researchers from Kaspersky Lab, Symantec and Blue Coat Systems independently reported that Trojan Destover, the malicious program used in the Sony Pictures attack, relied on a legitimate commercial driver called EldoS RawDisk to overwrite data and master boot records.
That same driver was used by a piece of malware called Shamoon that is believed to have been used in August 2012 to render up to 30,000 computers inoperable at Saudi Aramco, the national oil company of Saudi Arabia.
A previously unknown hacktivist group called the Cutting Sword of Justice took credit for the attack on Saudi Aramco through a series of posts on Pastebin. The group said it targeted the company because it was the main financial source for Saudi Arabia's Al Saud regime, which the group claimed supported oppressive government actions in countries like Syria, Bahrain, Yemen, Lebanon and Egypt.
The attack against Sony Pictures Entertainment was carried out by another previously unknown group called the Guardian of Peace (GOP), which claimed to have targeted the company because "Sony and Sony Pictures have made terrible racial discrimination and human rights violation, indiscriminate tyranny and restructuring in recent years."
The sharing of a third-party driver is not enough evidence to establish a direct link between the two malware programs, but it is possible that the Destover creators copied techniques from Shamoon, especially since the EldoS RawDisk driver is an unusual choice for implementing data wiping functionality.
Both Destover and Shamoon stored the EldoS RawDisk driver in their resource sections and both were compiled just days before being used in attacks, researchers from Kaspersky Lab said in a blog post.
Destover shares even more commonalities with another wiper malware program called DarkSeoul or Jokra that affected several banks and broadcasting organizations in South Korea in March 2013.
"The malware used in the Jokra attacks contained code that did not begin wiping the hard drive until a set time period expired," researchers from Symantec said in a blog post. "Destover is also configured to perform a delayed wipe. Furthermore, media outlets in South Korea have reported that a number of similar file names were used in both attacks."
The Jokra attacks were accompanied by website defacements that displayed a message from an obscure group of hackers called the Whois Team. "This is the beginning of our movement," the message said. "User accounts and all data are in our hands."
The GOP also left a message for Sony Pictures informing the company that it had obtained its internal data and both GOP's and Whois Team's messages were accompanied by images of skeletons, though this might be a mere coincidence.
"Just like DarkSeoul, the Destover wiper executables were compiled somewhere between 48 hours prior to the attack and the actual day of attack," the Kaspersky researchers said. "It is highly unlikely that the attackers spear-phished their way into large numbers of users, and highly likely that they had gained unfettered access to the entire network prior to the attack."
A more direct connection was established by Symantec between Destover and a backdoor program known as Volgmer that allows attackers to retrieve system information, execute commands, upload files, and download files for execution.
"Some samples of Destover report to a command-and-control (C&C) server that was also used by a version of Trojan.Volgmer crafted to attack South Korean targets," the Symantec researchers said. "The shared C&C indicates that the same group may be behind both attacks."
The apparent links between Destover and malware that was used to target South Korean organizations will likely fuel ongoing speculation that North Korea might be behind the attack against Sony Pictures Entertainment, supposedly as retaliation for an upcoming comedy film called "The Interview" in which two reporters are asked by the CIA to assassinate North Korean leader Kim Jong Un. North Korea reportedly denied its involvement in the attack.
These commonalities "do not prove that the crew behind Shamoon is the same as the crew behind both DarkSeoul and Destover," the Kaspersky researchers said. "But it should be noted that the reactionary events and the groups' operational and toolset characteristics all carry marked similarities. And, it is extraordinary that such unusual and focused acts of large scale cyber-destruction are being carried out with clearly recognizable similarities."
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