Pierluigi Paganini November 24, 2018

According to security reearchers at Trend Micro, the North Korea-linked APT group Lazarus recently targeted banks in Latin America.

The North Korea-linked APT group Lazarus recently targeted banks in Latin America, Trend Micro experts reported.

The activity of the Lazarus Group surged in 2014 and 2015, its members used mostly custom-tailored malware in their attacks and experts that investigated on the crew consider it highly sophisticated.

This threat actor has been active since at least 2009, possibly as early as 2007, and it was involved in both cyber espionage campaigns and sabotage activities aimed to destroy data and disrupt systems.

The group is considered responsible for the massive WannaCry ransomware attack, a string of SWIFTattacks in 2016, and the Sony Pictures hack.

Recently, the group was involved in several attacks aimed at stealing millions from ATMs across Asia and Africa.

The ATP group has been using this malware at least since 2016 to siphon millions of dollars from ATMs of small and midsize banks in Asia and Africa.

Now experts from Trend Micro have found a Lazarus backdoor on several machines belonging to financial institutions across Latin America. The malicious codes were installed by the APT group on the targeted machines on September 19.

“There seems to be a resurgence of activity from the group, and recent events show how their tools and techniques have evolved. Just last week they were found stealing millions from ATMs across Asia and Africa.” reads the analysis published by Trend Micro.

“We also recently discovered that they successfully planted their backdoor (detected by Trend Micro as BKDR_BINLODR.ZNFJ-A) into several machines of financial institutions across Latin America.”

The technique recently used by Lazarus resembles a 2017 wave of attacks that hit targets in Asia, at the time hackers used the FileTokenBroker.dll and a modularized backdoor.

In 2018 attacks, the Lazarus group used multiple backdoors, and also implemented a sophisticated technique that involves the three major components:

• AuditCred.dll/ROptimizer.dll (detected by Trend Micro as BKDR_BINLODR.ZNFJ-A) – loader DLL that is launched as a service
• Msadoz<n>.dll (detected by Trend Micro as BKDR64_BINLODR.ZNFJ-A) – encrypted backdoor
  n = number of characters in the loader dll’s filename
• Auditcred.dll.mui/rOptimizer.dll.mui (detected by Trend Micro as TROJ_BINLODRCONF.ZNFJ-A) – encrypted configuration file

Experts noticed that the loader DLL is installed as a service, it uses different names on different machines. The backdoor implements several capabilities, it can collect files and system information, download files and additional malware, launch/terminate/enumerate processes, update configuration data, delete files; inject code from files to other running process, utilize proxy, open reverse shell, and run in passive mode, where it opens and listens to a port to receive commands through it.

C&C information is contained in the encrypted configuration file, the backdoor requires a C&C connection for conducting activities.

“The Lazarus group is an experienced organization, methodically evolving their tools and experimenting with strategies to get past an organization’s defenses. The backdoors they are deploying are difficult to detect and a significant threat to the privacy and security of enterprises, allowing attackers to steal information, delete files, install malware, and more,” Trend Micro concludes.

Pierluigi Paganini

(Security Affairs – Hacking, Lazarus)

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