'APT-On-APT' Action

Cyber espionage hackers on occasion have bumped into one another in attack campaigns and inadvertently phished each other after stealing the same email addresses of targets. But this time, it was a case of turnabout.

While investigating a massive spear-phishing attack by a cyber espionage gang in March of last year, Kaspersky Lab researchers spotted what they say is the sign of a new form of cyber espionage activity: APT (advanced persistent threat) groups attacking other APTs. A cyber espionage group they call Naikon, which targets government and industry organizations in the Asia-Pacific region, got a response email from one of its targets, "The Security Office," asking to confirm that the "Secretariat" indeed had sent the email. A member of the Naikon gang sent an email reply in broken English purportedly from the Technical Assistant to the National Secretariat that basically said the message was legit.

That's when the targeted organization--another APT that Naikon apparently had unknowingly targeted in its phishing campaign--retaliated by crafting a phishing email of its own a few days later. "The email in this case originates from a government email … and is directed to the Naikon attackers. They decided to strike back at the attacker, a spy-on-spy sort of move," said Costin Raiu, head of Kaspersky's global research and analysis team, in a recorded presentation about the attack.

The message included an attachment that was supposedly a directory, and contained an infected screen saver file in an RAR archive file that Kaspersky confirmed contained malware. "They [Hellsing] are interested in infecting other APTs and learning about their operations," he said.

Raiu says it's a new twist to the APT. "Welcome to the APT wars," he said. "We're now in a world where nation-state APTs are fighting each other in counter-intel and intel-gathering mechanisms. Obviously, the goals are attribution: they want to know who's trying to infect me and what's been stolen or what can be stolen from my country or [from] my neighbors."

The group that hit back also targets the Asia-Pacific region -- mainly government and diplomatic organizations -- in its own cyber espionage attacks, and has been in action since around 2012, according to Kaspersky, which has dubbed the group "Hellsing" after some strings the attackers left behind in their malware.

"In the past, we’ve seen APT groups accidentally hitting each other while stealing address books from victims and then mass-mailing everyone on each of these lists. However, considering the targeting and origin of the attack, it seems more likely that this is an example of a deliberate APT-on-APT attack," Raiu said.

It was also the first time Kaspersky had seen Hellsing, which it says loads a custom backdoor that can download and upload files on the infected machine, as well as update and uninstall itself. Hellsing has targeted some 20 different organizations, mainly in Malaysia, the Philippines, India, Indonesia, and the US. 

Kaspersky Lab has posted a blog with screen shots and code samples.