Watering Hole Attacks Target South Korean Users With ActiveX Exploits
A new series of reconnaissance attacks targeting ActiveX objects has been associated with the North Korean-linked Andariel group, a known branch of the notorious Lazarus Group.
In May, the group was observed exploitnig an ActiveX zero-day vulnerability in a series of attacks on South Korean targets, mainly for reconnaissance purposes. A script injected into compromised websites would identify the visitors’ operating system and browser and check for ActiveX and running plugins from a specific list of ActiveX components if Internet Explorer was detected.
Highly active in recent months, the Andariel group has apparently launched a new reconnaissance attack against South Korean targets, by injecting their code into four other compromised websites. The attack, which was spotted on June 21, attempts to collect different object information than before.
Despite targeting objects it wasn’t targeting before, the newly discovered script is similar to the one used in May, which led Trend Micro to the conclusion that the same group of hackers is behind both campaigns.
Previously, the group collected targeted ActiveX objects on users’ Internet Explorer browser and only launched the zero-day exploit after identifying the right targets.
“Based on this, we believe it’s likely that the new targeted ActiveX objects we found could be their next targets for a watering hole exploit attack,” Trend Micro explains.
The new attack lasted until June 27 and targeted the visitors of a Korean non-profit organization’s website and those of three South Korean local government labor union websites.
The injected script, which had similar obfuscation and structure as the Andariel-linked script found in May, was designed to collect visitor information such as browser type, system language, Flash Player version, Silverlight version, and multiple ActiveX objects.
According to Trend Micro, the script was attempting to detect two additional ActiveX objects that were not previously targeted, namely o
ne related to a DRM (Digital Rights Management) software from a South Korean Document Protection Security vendor and another related to a South Korea-based voice conversion software company.
The script also included code to connect websocket to localhost. “The voice conversion software has websocket service listening on the local host so the injected script can detect the software by checking if they can establish a connection to ports 45461 and 45462, which the software uses,” Trend Micro explains.
The websocket verification, the security researchers say, could also be performed on Chrome and Firefox, in addition to Internet Explorer, which would suggest that the hackers have expanded their target base, aiming at the software and not just the ActiveX objects.
“Based on this change, we can expect them to start using attack vectors other than ActiveX,” Trend Micro notes.