ESET researchers recently discovered attempts to deploy Lazarus malware via a supply-chain attack (on less secure parts of the supply network) in South Korea. In order to deliver its malware, the attackers used an unusual supply-chain mechanism, abusing legitimate South Korean security software and digital certificates stolen from two different companies. The attack was made easier for Lazarus since South Korean internet users are often asked to install additional security software when visiting government or internet banking websites.

“To understand this novel supply-chain attack, you should be aware that WIZVERA VeraPort, referred to as an integration installation program, is a South Korean application that helps manage such additional security software. When WIZVERA VeraPort is installed, users receive and install all necessary software required by a specific website. Minimal user interaction is required to start such software installation,” explains Anton Cherepanov, ESET researcher who led the investigation into the attack. “Usually this software is used by government and banking websites in South Korea. For some of these websites it’s mandatory to have WIZVERA VeraPort installed,” adds Cherepanov.

Additionally, the attackers used illegally obtained code-signing certificates in order to sign the malware samples. Interestingly, one of these certificates was issued to the U.S. branch of a South Korean security company. “The attackers camouflaged the Lazarus malware samples as legitimate software. These samples have similar file names, icons and resources as legitimate South Korean software,” says Peter Kálnai, ESET researcher who analyzed the Lazarus attack with Cherepanov. “It’s the combination of compromised websites with WIZVERA VeraPort support and specific VeraPort configuration options that allows attackers to perform this attack,” adds Kálnai.

ESET Research has strong indications to attribute the attack to Lazarus, as it is a continuation of what KrCERT has called Operation BookCodes, attributed to Lazarus by some in the cybersecurity research community. The other reasons are typical toolset characteristics; detection (many tools are already flagged as NukeSped by ESET); the fact that the attack took place in South Korea, where Lazarus is known to operate; the unusual and custom nature of the intrusion and encryption methods used; and the setup of network infrastructure.

It must be noted that the Lazarus toolset is extremely broad, and ESET believes there are numerous subgroups. Unlike toolsets used by some other cybercriminal groups, none of the source code of any Lazarus tools has ever been disclosed in a public leak.

For more technical details about the latest Lazarus supply-chain attack, read the blogpost “Lazarus supply-chain attack in South Korea” on WeLiveSecurity. Make sure to follow ESET Research on Twitter for the latest news from ESET Research.