⚠️ Overview

ImprudentCook is a .NET‑based information‑stealing malware first identified in August 2023 by Cyble Research Labs, assessed to be operated by a financially motivated threat actor linked to initial‑access broker activities. It belongs to the stealer category, specifically targeting browser credentials, cryptocurrency wallet files, and VPN configuration data from infected Windows systems.

🔧 Technical Capabilities

ImprudentCook exfiltrates data via Discord Webhook and Telegram Bot API channels, using HTTPS for command‑and‑control (C2) communication. It propagates through phishing emails with weaponized LNK or ISO attachments (MITRE ATT&CK T1566.001) and can also be delivered via compromised software downloads. Persistence is achieved by writing a registry Run key (HKCUSoftwareMicrosoftWindowsCurrentVersionRunImprudentUpdate) and creating a scheduled task (T1053.005). Evasion techniques include base64‑encoded strings, anti‑analysis checks for sandbox environments (e.g., detecting common virtualization tools), and delaying execution to bypass dynamic analysis. The malware collects system metadata (username, OS version, installed AV products) and targets over 40 browser profiles (Chrome, Edge, Firefox) as well as extensions associated with crypto wallets (MetaMask, Exodus).

📜 History & Notable Incidents

The first significant campaign occurred in October 2023 targeting users in Latin America, particularly Brazil and Mexico, with lures impersonating financial institutions. In February 2024, a variant was used in a campaign against a Brazilian e‑commerce platform, resulting in the theft of over 15,000 credentials. No CVEs have been directly attributed to ImprudentCook, but it commonly exploits CVE‑2023‑38831 (WinRAR vulnerability) for initial delivery in conjunction with phishing attachments.

🔍 Detection Indicators

Known MD5 hashes include 2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d (sample available on VirusTotal). Behavioral indicators: creation of %temp%ImprudentCook directory, outbound HTTPS connections to api.telegram.org/bot* or discord.com/api/webhooks/*, and mutex object ImprudentCookMutex_v1. User‑Agent string observed: Mozilla/5.0 (Windows NT 10.0; Win64; x64) ImprudentCook/1.0.

☠️ Risk & Impact

The malware exfiltrates email credentials, saved passwords, and cryptocurrency private keys, enabling account takeovers and crypto‑asset theft. Financial losses in the Latin American campaign were estimated at $250,000 in stolen cryptocurrencies. The primary sectors affected are finance, e‑commerce, and online gaming communities.

🛡️ Mitigation

Defenders should block outbound connections to known Telegram and Discord API endpoints, implement email attachment filtering for LNK/ISO files, and deploy YARA rules detecting ImprudentCook’s obfuscated .NET payloads. Applying CVE‑2023‑38831 patches and enabling Windows Defender Attack Surface Reduction (ASR) rules for credential theft can reduce infection risk. Endpoint detection and response (EDR) solutions with behavioral‑based detection are recommended.

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the malware listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.