APT trends report Q2 2021 (DPRK-related paragraph 3)

Kaspersky Securelist

We have discovered Andariel activity using a revised infection scheme and custom ransomware targeting a broad spectrum of industries located in South Korea. In April, we observed a suspicious document containing a Korean file name and decoy uploaded to VirusTotal. It revealed a novel infection scheme and an unfamiliar payload. During the course of our research, Malwarebytes published a report with technical details about the same series of attacks, which attributed it to the Lazarus group. After a deep analysis we reached a different conclusion – that the Andariel group was behind these attacks. Code overlaps between the second stage payload in this campaign and previous malware from the Andariel group allowed for this attribution. Apart from the code similarity and the victimology, we found additional connections with the Andariel group. Each threat actor has a characteristic habit when they interactively work with a backdoor shell in the post-exploitation phase. The way Windows commands and their options were used in this campaign is almost identical to previous Andariel activity. The threat actor has been spreading the third stage payload since the middle of 2020 and leveraged malicious Word documents and files mimicking PDF documents as infection vectors. Notably, in addition to the final backdoor, we discovered one victim infected with custom ransomware. This ransomware adds another facet to this Andariel campaign, which also sought financial profit in a previous operation involving the compromise of ATMs.