Infostealer: The Malware That Silently Steals Your Credentials

An infostealer (or stealer) is a type of malware designed to silently extract credentials, passwords, session cookies, and sensitive data stored on an infected computer. Unlike ransomware, it operates in seconds without leaving visible traces, exfiltrating all harvested data to servers controlled by cybercriminals.

How does it work?

Infection typically begins when a user downloads a trojanized file: cracked software, a phishing email attachment, a fake browser update, or a malicious advertisement. Once executed, the stealer scans local browser databases (Chrome, Firefox, Edge) to extract all saved passwords, active session cookies, autofill data, and cryptocurrency wallets.

The collected data is compressed into a file called a “log” and sent to a command-and-control (C2) server or a private Telegram channel. The entire process takes less than 30 seconds. These logs are then sold on dark web marketplaces, cybercriminal forums, or specialized Telegram channels, sometimes for as little as $10.

The most active families include RedLine, Raccoon, Vidar, and LummaC2, all distributed as Malware-as-a-Service (MaaS) accessible even to attackers with limited technical skills.

Why does it matter?

Infostealers represent one of the most critical threats in cybersecurity today. According to the IBM X-Force report, stolen credentials are involved in over 30% of security incidents. A single infected workstation can compromise all of an employee’s access: corporate email, VPN, internal tools, and cloud accounts.

The volume is staggering: over 100 million new credential lines from stealer logs circulate daily across dark web channels. Businesses of all sizes are targeted, from startups to enterprises, because attackers focus on credentials rather than infrastructure.

The speed of the attack makes prevention alone insufficient. Even with up-to-date antivirus software and strict security policies, infections can still occur. This is why rapid detection of compromised credentials has become an essential pillar of any security strategy.

How Stealed protects you

Stealed monitors in real time the sources where infostealer logs are published: private Telegram channels, cybercriminal forums, and dark web marketplaces. When a credential matching one of your monitored domains is detected, you receive an immediate alert via Slack, Microsoft Teams, or webhook.

Unlike services like HaveIBeenPwned that focus on traditional breach databases, Stealed specifically analyzes stealer logs, the most active source of credential leaks today.

Learn more: read our comprehensive guide on infostealers for a detailed analysis of stealer families, stolen data types, and protection measures.

Start monitoring for free to find out if your credentials are circulating in infostealer logs.