NS-STEALER Uses Discord Bots to Exfiltrate Your Secrets from Popular Browsers

Cybersecurity researchers have discovered a new Java-based “sophisticated” information stealer that uses a Discord bot to exfiltrate sensitive data from compromised hosts.

The malware, named NS-STEALER, is propagated via ZIP archives masquerading as cracked software, Trellix security researcher Gurumoorthi Ramanathan said in an analysis published last week.

The ZIP file contains within it a rogue Windows shortcut file (“Loader GAYve”), which acts as a conduit to deploy a malicious JAR file that first creates a folder called “NS-<11-digit_random_number>” to store the harvested data.

To this folder, the malware subsequently saves screenshots, cookies, credentials, and autofill data stolen from over two dozen web browsers, system information, a list of installed programs, Discord tokens, Steam and Telegram session data. The captured information is then exfiltrated to a Discord Bot channel.

“Considering the highly sophisticated function of gathering sensitive information and using X509Certificate for supporting authentication, this malware can quickly steal information from the victim systems with [Java Runtime Environment],” Ramanathan said.

“The Discord bot channel as an EventListener for receiving exfiltrated data is also cost-effective.”

The development comes as the threat actors behind the Chaes (aka Chae$) malware have released an update (version 4.1) to the information stealer with improvements to its Chronod module, which is responsible for pilfering login credentials entered in web browsers and intercepting crypto transactions.

Infection chains distributing the malware, per Morphisec, leverage legal-themed email lures written in Portuguese to deceive recipients into clicking on bogus links to deploy a malicious installer to activate Chae$ 4.1.

But in an interesting twist, the developers also left behind messages for security researcher Arnold Osipov – who has extensively analyzed Chaes in the past – directly within the source code, expressing gratitude for helping them improve their “software.”