Pierluigi Paganini February 03, 2023

Russia-linked threat actor Gamaredon employed new spyware in cyber attacks aimed at public authorities and critical information infrastructure in Ukraine.

The State Cyber Protection Centre (SCPC) of Ukraine warns of a new wave of targeted attacks conducted by the Russia-linked APT group Gamaredon (aka Shuckworm, Actinium, Armageddon, Primitive Bear, UAC-0010, and Trident Ursa). The attacks aimed at public authorities and critical information infrastructure in Ukraine. The government experts pointed out that the threat actor continues to evolve its TTPs to avoid detection.

Currently, the Gamaredon group is using the GammaLoad and GammaSteel SPZs in their campaigns. The former is a VBScript used to download next-stage VBScript from a remote server. GammaSteel is a PowerShell script used to conduct reconnaissance and execute additional commands.

The attack chain starts with spear-phishing messages with a .RAR attachment named “12-1-125_09.01.2023.” The .RAR archive contains the .LNK file named “Запит Служба безпеки України 12-1-125 від 09.01.2023.lnk” (“Request of the Security Service of Ukraine 12-1-125 dated 09.01.2023.lnk”).

Upon opening the .LNK file, it uses the System Binary Proxy Execution technique through the execution of Windows-native binary (designed to execute Microsoft HTML Application (HTA) files (mshta.exe)) to download a file via the URL hxxps://secureurl[.]shop/09.01_otck/quicker[.]rtf . The government experts noticed that access to the file is allowed only from IP addresses in the Ukrainian address space.

“The current activity of the UAC-0010 group is characterized by an approach to the multi-stage loading and execution of payloads of WPS, which is used to maintain control over infected hosts. Such payloads are similar types of malware, which are developed by attackers to perform similar behavioral patterns.” reads the alert published by the SCPC. “Currently, the UAC-0010 group uses the GammaLoad and GammaSteel SPZs in their campaigns.”

One of the methods of getting the C2 IP address relies on the usage of legitimate third-party
services, such as Telegram and cloudflare-dns[.]com.

Another method consists of pinging the subdomain Write[.]mohsengo[.]shop with WMI query and
retrieving the ProtocolAddress value to obtain the C2 IP address.

The State Cyber Protection Centre published a technical report that provides details for each stage of the attack chain.

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Pierluigi Paganini

(SecurityAffairs – hacking, Gamaredon)