A new information-stealing malware, ACRStealer, is leveraging legitimate platforms like Google Docs and Steam to carry out its attacks, according to research from the AhnLab Security Intelligence Center (ASEC). This malware, which initially appeared in mid-2024 as a beta version, has seen a significant increase in distribution since 2025, with February’s volume mirroring January’s and indicating a potential surge.
It is worth noting that, according to Hudson Rock’s report, infostealers have become the biggest threat to critical infrastructure. The report reveals that computers belonging to the US Army, Navy, and even the FBI have been compromised, with stolen data available on the dark web for as little as $10.
In the ongoing campaign, ASEC’s monitoring confirms that ACRStealer is spread through software cracks and key generators, commonly used for software piracy, and the malware is frequently disguised as these illegal programs.
While Lumma Stealer and Vidar have been dominant infostealers distributed this way, researchers observed that ACRStealer’s presence is growing rapidly. According to their report, the distribution trend of ACRStealer from June 2024 to February 2025 indicates a dramatic rise in 2025.
ACRStealer boasts a range of malicious capabilities. It can detect installed antivirus solutions, steal cryptocurrency wallets and login credentials, extract browser data, harvest FTP credentials, and read all text files. This stolen information allows cybercriminals to target financial assets and personal accounts. Stolen credentials grant access to email, social media, and banking services. This data can also be used for identity theft or sold on dark web markets.
A key feature is ACRStealer’s C2 server communication. Instead of embedding the server’s IP, it uses a Dead Drop Resolver (DDR). This method involves the malware contacting a legitimate service, such as Google Docs or Steam, to retrieve the C2 server’s domain. ASEC has identified several platforms used as intermediary C2s, including Steam, telegra.ph, and various forms of Google Docs (Forms and Presentations).
This approach allows attackers to easily change the C2 domain if it is compromised without needing to update the malware itself. They simply modify the information within the intermediary C2.
The actual C2 domain, retrieved from the intermediary C2, is combined with a hardcoded UUID (Universally Unique Identifier) to create the URL for downloading encrypted configuration data. This data contains crucial information like target programs, additional malware URLs, file extensions, and target extension IDs.
The configuration file specifies a wide range of data to be stolen, including browser data, text files, cryptocurrency wallets, FTP information, chat program information, email client information, remote program information, terminal program information, VPN information, password manager information, database (DB) information, and browser extension plugin information.
Also, it targets numerous programs, from browsers like Chrome and Firefox to cryptocurrency wallets like Binance and Electrum, chat programs like Telegram and Signal, and various browser plugins. Collected files are often compressed before transmission.
AhnLab’s research highlights ACRStealer’s adaptable approach, constantly changing platforms and the locations of C2 information within them. It operates as Malware-as-a-Service (MaaS), making infection tracking difficult.
However, preventative measures can be taken. This involves avoiding websites distributing cracks and key generators, and downloading software only from official sources. Additionally, be cautious with links and attachments in unsolicited communications, enable multi-factor authentication (MFA) for added security, and maintain an active anti-malware solution.