Bank customers in the Central Asia region have been targeted by a new strain of Android malware codenamed Ajina.Banker since at least November 2023 with the goal of harvesting financial information and intercepting two-factor authentication (2FA) messages.
Singapore-headquartered Group-IB, which discovered the threat in May 2024, said the malware is propagated via a network of Telegram channels set up by the threat actors under the guise of legitimate applications related to banking, payment systems, and government services, or everyday utilities.
"The attacker has a network of affiliates motivated by financial gain, spreading Android banker malware that targets ordinary users," security researchers Boris Martynyuk, Pavel Naumov, and Anvar Anarkulov said.
Targets of the ongoing campaign include countries such as Armenia, Azerbaijan, Iceland, Kazakhstan, Kyrgyzstan, Pakistan, Russia, Tajikistan, Ukraine, and Uzbekistan.
There is evidence to suggest that some aspects of the Telegram-based malware distribution process may have been automated for improved efficiency. The numerous Telegram accounts are designed to serve crafted messages containing links -- either to other Telegram channels or external sources -- and APK files to unwitting targets.
The use of links pointing to Telegram channels that host the malicious files has an added benefit in that it bypasses security measures and restrictions imposed by many community chats, thereby allowing the accounts to evade bans when automatic moderation is triggered.
Besides abusing the trust users place in legitimate services to maximize infection rates, the modus operandi also involves sharing the malicious files in local Telegram chats by passing them off as giveaways and promotions that claim to offer lucrative rewards and exclusive access to services.
"The use of themed messages and localized promotion strategies proved to be particularly effective in regional community chats," the researchers said. "By tailoring their approach to the interests and needs of the local population, Ajina was able to significantly increase the likelihood of successful infections."
The threat actors have also been observed bombarding Telegram channels with several messages using multiple accounts, at times simultaneously, indicating a coordinated effort that likely employs some sort of an automated distribution tool.
The malware in itself is fairly straightforward in that, once installed, it establishes contact with a remote server and requests the victim to grant it permission to access SMS messages, phone number APIs, and current cellular network information, among others.
Ajina.Banker is capable of gathering SIM card information, a list of installed financial apps, and SMS messages, which are then exfiltrated to the server.
New versions of the malware are also engineered to serve phishing pages in an attempt to collect banking information. Furthermore, they can access call logs and contacts, as well as abuse Android's accessibility services API to prevent uninstallation and grant themselves additional permissions.
Google told The Hacker News that it did not find any evidence of the malware being propagated via the Google Play Store and that Android users are protected against the threat by Google Play Protect, which is on by default on Android devices with Google Play Services.
"The hiring of Java coders, created Telegram bot with the proposal of earning some money, also indicates that the tool is in the process of active development and has support of a network of affiliated employees," the researchers said.
"Analysis of the file names, sample distribution methods, and other activities of the attackers suggests a cultural familiarity with the region in which they operate."
The disclosure comes as Zimperium uncovered links between two Android malware families tracked as SpyNote and Gigabud (which is part of the GoldFactory family that also includes GoldDigger).
"Domains with really similar structure (using the same unusual keywords as subdomains) and targets used to spread Gigabud samples and were also used to distribute SpyNote samples," the company said. "This overlap in distribution shows that the same threat actor is likely behind both malware families, pointing to a well-coordinated and broad campaign."
