An unidentified cybercrime threat actor has recently been observed targeting Spanish- and Portuguese-speaking individuals in Mexico, Peru, and Portugal, aiming to compromise their online banking accounts.
The campaign, known as Operation CMDStealer, utilizes tactics such as LOLBaS (living-off-the-land binaries and scripts) and CMD-based scripts to carry out malicious activities, according to a report by the BlackBerry Research and Intelligence Team. Based on artifact analysis, the cybersecurity company has attributed this campaign to a Brazilian threat actor.
The attack chain primarily relies on social engineering, utilizing Portuguese and Spanish emails with tax- or traffic violation-themed lures to trigger infections and gain unauthorized access to victims’ systems.
These emails contain an HTML attachment that conceals code to fetch the next-stage payload from a remote server in the form of a geofenced RAR archive file. Within the archive, a .CMD file houses an AutoIt script that downloads a Visual Basic Script, enabling the theft of Microsoft Outlook and browser password data.
BlackBerry noted that the use of LOLBaS and CMD-based scripts allows the threat actor to evade detection by traditional security measures. By leveraging built-in Windows tools and commands, they can bypass endpoint protection platform (EPP) solutions and security systems. The harvested information is then transmitted back to the attacker’s server via an HTTP POST request method.
The Canadian cybersecurity company highlighted that the threat actor behind Operation CMDStealer appears to have a specific interest in targeting online business accounts in Mexico, likely due to their better cash flow.
This campaign adds to the growing list of financially motivated malware campaigns originating from Brazil. Additionally, recent findings by ESET have exposed the tactics employed by a Nigerian cybercrime ring involved in complex financial fraud scams, including business email compromise, which targeted individuals, banks, and businesses globally over a period of several years.
