Bitdefender researcher have recently analyzed a malware sample that has been found to be very similar to something that a cybercriminal group, named DarkHotel, used to operate for nearly a decade.
The DarkHotel threat actors have been known to operate by targeting thousands of businesses across the world using the Wi-Fi infrastructure in hotels. Blending high-level spear phishing techniques with advanced malware and other complex attack avenues, the group has been able to operate for years without drawing any attention from law enforcement, apart for the few times some of their malware samples were documented by security researchers.
Unlike their usual way of compromising victims, the recently analyzed sample uses a new payload delivery mechanism rather than the traditional zero-day exploitation technique. Basically, instead of compromising a hotel’s Wi-Fi network to get to their victims, the new campaign blends social engineering with a relatively complex Trojan to infect a really select pool of victims.
Even more interesting is that if past DarkHotel campaigns used to target corporate research and development personnel, CEOs and other senior corporate officials, the new attack seems focused on politics rather than financial gains, at least judging from the content of the spear phishing email.
The social engineering part of the attack involves a very carefully crafted phishing email targeted to one person at a time, promising an attachment that contains sensitive political information about North Korea. In fact, it even shows a list of alleged contacts in the North Korean capital referencing organizations such as UN, UNICEF, and the World Food Programme.
Ironically, the decoy document even contained a warning message about spammer and ensuring privacy, encouraging recipients to use the Bcc address field to lessen the chances of spammers getting it. In addition to improving privacy, the document also said that it is also easier for readers to get to the actual email, rather than scrolling through the recipients first.
After opening the attachment, a multi-stage Trojan download would covertly install multiple malicious components designed to not only gain complete control over the targeted device, but also ensure persistency while dodging the victim’s security defenses.
The use of valid digital certificates, multi-stage payloads, carefully crafted political spear phishing messages, and cherry-picked victims could suggest the group is government-sponsored. However, is nearly impossible know that for sure when it comes to the cyber world, but it is clear that a sudden shift in the DarkHotel’s group behavior has occurred.
For more details about the APT, check out the full Inexmar technical research.