A new report links North Korea to the Lazarus APT Group

Pierluigi Paganini May 31, 2017

Moscow-based threat intelligence firm Group-IB published a report that details evidence linking the Lazarus APT Group to North Korea.

Researchers at security firm Group-IB released a report that links the notorious Lazarus APT to North Korea.

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.  Security researchers discovered that North Korean Lazarus APT group was behind recent attacks on banks, including the Bangladesh cyber heist.

According to security experts, the group was behind, other large-scale cyber espionage campaigns against targets worldwide, including the Troy Operation, the DarkSeoul Operation, and the Sony Picture hack.

According to the experts from Group-IB, the attacks against the SWIFT systems used by banks worldwide left the most clues.

The Lazarus APT group conducted massive reconnaissance operations before the banks attack in order to gather information on the infrastructure of the targets.

“We have detected and thoroughly analyzed the C&C infrastructure used by Lazarus,” explained Dmitry Volkov, Head of Threat Intelligence Department. “Our research shows how hackers gained access to the banks’ information systems, what malware they used, and who their attempts were aimed at.”

Investigating the Group-IB activity the researchers analyzed the complex botnet infrastructure used by the hackers.
To make harder the investigation of the attribution of the attacks, the cyberspies used a three-layer architecture of compromised servers that communicate through SSL encrypted channels.

“In addition to encrypted traffic, data sent through SSL channel was additionally encrypted. The attackers achieved anonymity by employing a legitimate VPN client – SoftEther VPN. In some cases, they also used corporate web servers that were part of the attacked infrastructure.” states the report published by Group-IB.

Lazarus APT 3-Layer Architecture

According to the researchers, the APT group changed its TTPs after the publication of the Operation Blockbuster report that revealed much information about the activity of the crew.

“According to our investigation of the Lazarus infrastructure, the threat actors connected to the end C&C layer (Layer3) from two North Korean IP addresses and The second IP-address relates to Potonggang District, perhaps coincidentally, where National Defence Commission is
located — the highest military body in North Korea” continues the report.

Investigating the Lazarus attack, Group-IB discovered the hackers used two IP addresses belonging to the C&C server infrastructure.

The first is is assigned to a company in China named China Netcom, but according to Group-IB’s sources the range of IPs was assigned to North Korea

The second IP address,, points to  North Korean Internet service provider because it is allocated to the Potonggang District. This is the same District where the military National Defence Commission is located.

“ belongs to an autonomous system China Netcom. However, some sources indicate that the set of IPs is assigned to North Korea. refers to a North Korean Internet service provider. The Whois service indicates that this address is allocated to the Potonggang District, perhaps coincidentally, where Natinal Defence Commission is located — the highest military body in North Korea”

The researchers also discovered that the Lazarus APT Group is masquerading its operations as Russian hackers. The group used false flags in its malware to deceive the investigators and to attribute the attack to the Russian hackers.

Group-IB experts, like peers from security firm BAE, discovered Russian words in the source code of the malware, but they noticed an incorrect use of the words.

Hackers also leveraged Flash and Silverlight exploits used by Russian state-sponsored hackers, they also used the Enigma Protector, an anti-tampering system for executable files developed by a Russian company.

“They added specific debugging symbols and strings containing Russian words to a new version of Client_TrafficForwarder, a
module designed to proxy network traffic.” continues the report. “To protect their executables, they used Enigma Protector, a commercial product, which was created by a Russian software developer. They also used exploits for Flash and SilverLight from sets of exploits created by Russian-speaking hackers. These masquerade techniques did initially mislead some researchers who conducted express analysis of malicious code.”

I don’t want to tell you more, for more details on the Group-IB investigation give a look at the interesting report that also includes IOCs about the malware used in recent operations attributed to the Lazarus Group.

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Pierluigi Paganini

(Security Affairs – Lazarus APT Group, North Korea)

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