Below research is reflecting our observations during month of March 2022. We also would like to thank Maria Jose Erquiaga for her contribution in introduction and support during the process of writing.

Overview

As the Russian-Ukrainian war continues over conventional warfare, cybersecurity professionals witnessed their domain turning into a real frontier. Threat actors picking sides [1], group members turning against each other [2], some people handing out DDoS tools [3], some people blending in to turn it into profit [4], and many other stories, proving that this new frontier is changing daily, and its direct impact is not limited to geographical boundaries.

While attacks seem to be evolving daily, it is challenging for one to stay up to date with all that is going around. Therefore, we believe that it is important to distinguish between information and actionable intelligence. In Cisco Global Threat Alerts, we would like to share our observations related to this conflict during March of 2022 and discover how we can turn them into actionable intelligence together.

Threat Actors in the Russian-Ukrainian Conflict

Since the rapid escalation of the conflict in 2022, security researchers and analysts have been gathering information regarding the adversarial groups, malware, techniques, and types of attacks implemented [1, 5, 6]. Some of the groups and malware related to the conflict are described in Table 1:

Table 1: Threat actors and their relations

Gamaredon

Gamaredon group, also known as Primitive Bear, Shuckworm and ACTINIUM, is an advanced persistent threat (APT) based in Russia. Their activities can be traced back as early as 2013, prior to Russia's annexation of the Crimean Peninsula. They are known to target state institutions of Ukraine and western government entities located in Ukraine. Ukrainian officials attribute them to Russian Federal Security Service, also known as FSB [17].

Gamaredon often leverages malicious office files, distributed through spear phishing as the first stage of their attacks. They are known to use a PowerShell beacon called PowerPunch to download and execute malware for ensuing stages of attacks. Pterodo and QuietSieve are popular malware families that they deploy for stealing information and various actions on objective [18].

We were able to collect network IoC's related to Gamaredon infrastructure. During our initial analysis, most of the indicators were not attributed directly to any specific malware and they were rather listed as part of Gamaredon's infrastructure. Therefore, we wanted to analyze their infrastructure to understand their arsenal and deployment in greater detail.

Network Infrastructure

The first part of this research is focused on WHOIS record analysis. We observed that Gamaredon domains were dominantly registered by REG[.]RU. Creation dates are going back as early as February 2019 and have a changing pattern for the registrant email. Until August 2020, we observed that message-yandex.ru@mail[.]ru was the main registrant email. Later, it shifted to macrobit@inbox[.]ru, mixed with the occasional usage of message-yandex.ru@mail[.]ru and tank-bank15@yandex[.]ru. Domain creation dates in some of the WHOIS records are as recent as March 2022.

Other than WHOIS information, the domains we observed that were related to Gamaredon campaigns had a distinguishing naming convention. While dataset consisted of domain names (without TLDs) varying between 4 to 16 characters, 70% percent of them were between 7 to 10 characters. Combined with a limited group of top-level domains (TLDs) used (see Table 2), this leads us to a naming pattern for further attribution. Additionally, the usage of TLDs on domain creation seems to be rotating.

Table 2: TLD distribution and time in use

In the case of domain resolutions, we aimed to analyze the distribution of autonomous system numbers (ASN) used by resolved IP addresses (see Table 3). Once more, the owner REG[.]RU is leading the list, owning most of the domains. TimeWeb was the second this time, with 28% of the domains we found to be related to Gamaredon activities. Domains having '. online' and '.ru' TLDs are regularly updating their IP resolutions, almost daily.

Table 3: Distribution of IP addresses per ASN and owner

Tooling

After understanding the infrastructure, let's proceed with their arsenal. We looked at associated file samples for the domains through Umbrella and Virustotal. A sample of the results can be seen below. Referring to a file type, we can see that the Gamaredon group prefers malicious office documents with macros. Also, they are known to use Pterodo, which is a constantly evolving custom backdoor [8, 18].

Table 4: Domains, files (hash and type), and malware name associated to the Gamaredon group

After reviewing the behaviors of the associated malicious samples, it is easier to build attribution between the malicious domain and the corresponding sample. IP addresses resolved by the domain are later used to establish raw IP command and control (C2) communication with a distinguishing URL pattern.