Threats Tagged 'browser data exfiltration'

This analysis examines a sophisticated Vidar infostealer variant that employs a custom virtual machine to obfuscate its malicious code through proprietary bytecode interpretation. The malware implements extensive anti-analysis measures including debugger detection via NtQueryInformationProcess and RDTSC timing checks, sandbox evasion by identifying antivirus processes and checking system resources, and environment fingerprinting. Vidar targets credentials from web browsers including Chromium and Gecko-based extensions, Azure authentication tokens, FileZilla FTP credentials, and captures screenshots. It utilizes SeDebugPrivilege for elevated access, creates hidden desktops for browser automation, and exfiltrates stolen data through Telegram channels. The malware performs cleanup operations to remove execution artifacts and proxies DLL execution through rundll32.exe to blend with legitimate Windows processes.

A sophisticated ClickFix campaign targets both Windows and macOS users through fake CAPTCHA pages that trick victims into executing malicious commands. The macOS variant deploys an AppleScript-based infostealer that harvests sensitive data including keychain databases, credentials, and session cookies from 12 browsers, over 200 browser extensions, and 16 cryptocurrency wallets. The malware employs a persistent, non-closable dialog box mimicking legitimate system prompts to force victims into providing their system password. Stolen session cookies enable attackers to bypass multi-factor authentication by hijacking active sessions. The campaign uses client-side JavaScript to filter victims by user-agent, directing desktop users to OS-specific payloads while ignoring mobile devices. Latest macOS updates include native terminal security warnings designed to alert users against pasting potentially malicious commands.