Infostealers: Why Saved Passwords Get You Owned

A Beaumont oilfield services company had an employee download what looked like a PDF invoice from an email. The file was actually an infostealer—a type of malware specifically designed to harvest passwords, cookies, and credentials from infected computers.

Within hours, the attacker had extracted every saved password from the employee's browser: their email, their VPN, their company cloud storage, their client portal logins. The attacker used those credentials to access the company's systems, spent two weeks mapping out their network, and then ransomware hit on a Friday night.

The initial infection cost nothing—a fake PDF. The total damage: six figures and weeks of downtime.

Infostealers are one of the most common ways attackers get initial access to business networks. They work because people save passwords in browsers, and browsers aren't designed to be secure credential stores.

How infostealers actually work

An infostealer is malware that runs on your computer and steals information. The most common delivery:

1. Phishing email with a malicious attachment or link
2. Fake software downloads from search results or unofficial sites
3. Pirated software that bundles infostealers with the "free" program
4. Malvertising where attackers pay for search ads that lead to malware

Once installed, modern infostealers like RedLine, Raccoon, Vidar, and Lumma Stealer will:

• Extract saved passwords from Chrome, Firefox, Edge, and other browsers. Browser password storage is designed for convenience, not security.
• Grab browser cookies that let attackers hijack your logged-in sessions without needing passwords.
• Capture system information including IP address, hostname, installed software.
• Steal cryptocurrency wallet data from browser extensions and local wallet files.
• Export VPN credentials if you saved passwords in your VPN client.
• Pull saved FTP credentials and remote desktop connection details.

All of this gets packaged up and sent to the attacker, usually within minutes of infection.

What can go wrong

Immediate account takeover: If the infected computer has saved passwords for business accounts, attackers have those passwords now.

Session hijacking: Even without passwords, stolen browser cookies let attackers impersonate you in active sessions. They can access web apps without logging in.

Lateral movement: If the infected computer has VPN access, remote desktop credentials, or saved connections to internal systems, attackers can walk into your network.

Credential stuffing fuel: Stolen credentials go into databases that attackers use to try the same passwords on other services.

Data theft: Email access lets attackers read your conversations, find valuable data, and impersonate you to clients and vendors.

Ransomware delivery: Infostealer access is often sold to ransomware operators who then use it to reach high-value targets.

What it costs

• Incident response: $5,000 to $50,000 for a professional cleanup after infostealer infection
• Ransomware costs: If the infostealer access leads to ransomware, $50,000 to $500,000+ total
• Account recovery: Time spent resetting passwords, recovering compromised accounts, and verifying system integrity
• Business interruption: Days to weeks if attackers use stolen access to disrupt operations
• Data exposure: If email or cloud storage was accessed, notification requirements and liability

Vendor questions (copy/paste)

"How does your endpoint protection detect and block infostealer malware? What do your detection rates look like for these threats?"

"We have employees on personal devices that access company email. How do we protect those devices without managing them?"

"What's your recommendation for password management that doesn't rely on browser-saved passwords?"

"How do I check if an employee's computer has been compromised by an infostealer?"

"We clicked something we shouldn't have. What are the signs that an infostealer might be running on our system?"

Minimum viable implementation

1. Deploy a real password manager and stop using browser-saved passwords. Browser password storage is not secure. Services like 1Password, Bitwarden, or Dashlane store passwords in encrypted vaults that infostealers can't easily access. Cost: $3-10 per user per month on business plans.

2. Enable browser-based protections where available. Chrome, Edge, and Firefox all have enhanced protections that can help detect some malware. Make sure they're enabled on all business computers.

3. Implement endpoint detection and response (EDR) on business computers. Good EDR can detect the behaviors infostealers exhibit—unusual file writes, credential access, network connections to known-bad destinations. This catches infections that traditional antivirus misses.

4. Restrict what employees can download. Use application controls to block executables from running outside approved locations. Many infostealers need to run as executable files.

5. Patch your operating system and software. Infostealers exploit vulnerabilities to run. Keeping systems updated closes those doors.

6. Block personal email and non-work software on work computers where possible. If employees can't download things from random websites or pirated software sites, infostealer delivery becomes harder.

7. Have a response plan for when someone clicks something they shouldn't. Time matters with infostealers. If someone downloads something suspicious, the response should be immediate: disconnect from the network, scan with antivirus, reset passwords from a clean device.

8. Segment your network. If one computer is compromised, it shouldn't have direct access to your server, financial systems, or other sensitive resources. Network segmentation limits what attackers can reach.

When to hire help

Call someone today if:

• An employee downloaded something suspicious and you're not sure if it's an infostealer
• You're seeing unusual activity—password reset emails you didn't request, account lockouts, unfamiliar devices in your security logs
• An employee's computer is acting strange after opening an attachment

Call someone this week if:

• You want to audit whether your endpoints are protected against infostealers
• You need help deploying a password manager and getting your team off browser-saved passwords
• You want to set up EDR and learn how to use it

You can probably handle it yourself if:

• You already have a password manager in place and your team uses it instead of browser passwords
• Your endpoint protection is current and you're monitoring alerts
• Your employees know not to download software from unknown sources

The browser's "save password" prompt is convenient. It's also a direct line from an employee's click to your entire credential database. The tradeoff isn't worth it.