A financially-motivated malware campaign has compromised over 800 WordPress websites to deliver a banking trojan dubbed Chaes targeting Brazilian customers of Banco do Brasil, Loja Integrada, Mercado Bitcoin, Mercado Livre, and Mercado Pago.
First documented by Cybereason in November 2020, the info-stealing malware is delivered via a sophisticated infection chain that’s engineered to harvest sensitive consumer information, including login credentials, credit card numbers, and other financial information.
“Chaes is characterized by the multiple-stage delivery that utilizes scripting frameworks such as JScript, Python, and NodeJS, binaries written in Delphi, and malicious Google Chrome extensions,” Avast researchers Anh Ho and Igor Morgenstern said. Chaes’ ultimate goal is to intercept logins from popular Brazilian banking sites and steal Chrome credentials. “
The attack sequence is triggered when users visit one of the infected websites, upon which a pop-up is displayed, urging them to install a fake Java Runtime application. If the user follows the prompts, the malicious installer will launch a complicated malware delivery process that eventually leads to the deployment of multiple modules.
- Online – A Delphi module used to fingerprint the victim and transmit the system information to a command-and-control (C2) server
- Mtps4 (MultiTela Pascal) – A Delphi-based backdoor whose main purpose is to connect to the C2 server and wait for a responding Pascal Script to execute
- Chrolog (ChromeLog) – A Google Chrome password stealer written in Delphi
Avast stated that they have shared their findings with Brazilian CERTs to stop the spread of the malware. However, Chaes-related artifacts are still found on infected sites.
“Chaes exploits many websites containing CMS WordPress to serve malicious installers,” the researchers concluded. “The Google Chrome extensions are able to steal users’ credentials stored in Chrome and collect users’ banking information from popular banking websites. “