Shuyal Stealer is an advanced infostealer malware designed to target 19 different web browsers, enabling it to harvest a wide range of sensitive user data. It conducts comprehensive system reconnaissance, gathering detailed hardware information and user-specific data to tailor its operations and evade detection. The malware disables Windows Task Manager, preventing users and administrators from easily terminating its processes. Persistence is achieved by inserting itself into the Windows startup folder, ensuring execution upon system reboot. Shuyal Stealer collects credentials stored in multiple browsers, captures clipboard contents, takes screenshots, and steals Discord authentication tokens, thereby compromising both personal and organizational accounts. Data exfiltration is performed covertly via a Telegram bot, which receives compressed data using PowerShell scripts, enhancing stealth and reducing forensic footprints. The malware also employs self-deletion techniques to remove traces after execution, complicating incident response efforts. Despite the lack of a CVE identifier or known exploits in the wild, its extensive capabilities and evasion tactics make it a significant threat. The malware’s targeting of a broad spectrum of browsers increases its attack surface, affecting users across various platforms and increasing the likelihood of successful data theft. The use of Telegram for data exfiltration is notable for its difficulty to block without impacting legitimate communications. The malware’s tactics align with multiple MITRE ATT&CK techniques, including credential access, persistence, defense evasion, and command and control communications.

For European organizations, Shuyal Stealer presents a considerable risk to confidentiality and integrity of sensitive information. The theft of browser-stored credentials can lead to unauthorized access to corporate accounts, internal systems, and cloud services, potentially enabling lateral movement and data breaches. Clipboard capture and screenshot capabilities increase the risk of leaking sensitive information such as passwords, financial data, or confidential documents. Discord token theft may expose internal communications or allow attackers to impersonate users in collaboration platforms. Disabling Task Manager and self-deletion hinder detection and remediation, prolonging attacker presence and increasing damage potential. The malware’s persistence mechanism ensures ongoing risk until fully eradicated. The use of Telegram for data exfiltration complicates network monitoring and blocking efforts, as Telegram traffic is often allowed in corporate environments. Organizations with remote or hybrid workforces using diverse browsers are particularly vulnerable. The broad browser targeting means that even users who do not use mainstream browsers may still be affected. Overall, the malware could facilitate espionage, financial fraud, and reputational damage, especially in sectors handling sensitive personal or business data.

European organizations should implement multi-layered defenses tailored to Shuyal Stealer’s capabilities. First, enforce strict application control policies to prevent unauthorized execution of PowerShell scripts and unknown binaries, especially those attempting to modify startup folders. Deploy endpoint detection and response (EDR) solutions with behavioral analytics to detect disabling of Task Manager and unusual process activities. Regularly audit and restrict access to stored browser credentials and encourage use of password managers with master passwords rather than browser storage. Monitor clipboard access and implement controls to limit sensitive data exposure. Network monitoring should include detection of unusual Telegram API traffic or connections to known malicious Telegram bots, with the possibility of blocking or alerting on such traffic. Conduct user awareness training focusing on phishing and social engineering, as initial infection vectors often rely on user interaction. Maintain up-to-date backups and incident response plans to quickly recover from infections. Employ browser hardening techniques and keep all browsers updated to reduce vulnerabilities. Finally, implement strict privilege management to limit malware’s ability to persist and evade detection.