Ashetrace
To check a computer for an infostealer, work from the outside in: disconnect it if the signs are strong, review browser extensions and startup persistence, run an offline scan that boots before Windows, and verify your accounts from a separate clean device. Change passwords only after the machine is clean, because a password typed on an infected device gets stolen again. Flashpoint tracked 11.1 million infostealer-infected devices in 2025.
- Flashpoint tracked 11.1 million infostealer-infected devices in 2025, yielding roughly 3.3 billion credentials, cookies and tokens.
- Infostealers often run once and exit, so a normal on-demand scan can miss them. An offline (boot-time) scan catches malware that hides from the running OS.
- Change passwords only after the device is clean. A reset on an infected machine simply feeds the attacker a fresh credential.
- Verify accounts from a second, trusted device, since a compromised machine can hide the very activity you're checking for.
- Stolen credentials were the top initial-access action in 22% of breaches (Verizon 2025 DBIR), which is why device cleanup and exposure checks go together.
How do I know if I should check for an infostealer?
Check when you see credential-related trouble you can't explain: accounts logged into from unknown locations, passwords that keep leaking after you change them, or several accounts alerting at once. Infostealers are built for exactly this, and they operate at scale. Flashpoint tracked 11.1 million infected devices in 2025, producing about 3.3 billion credentials, cookies and tokens (Flashpoint).
The catch is that many infostealers leave no visible symptom. They run once, copy the browser's saved logins and cookie store, exfiltrate, and sometimes delete themselves. The theft persists as valid credentials and cookies even after the malware is gone, which is why stolen credentials were the top initial-access action in 22% of breaches (Verizon 2025 DBIR). Absence of symptoms is not proof of safety.
What is the safe order to check a computer?
Stolen credentials were the top initial-access action in 22% of breaches, so order matters when you clean up (Verizon 2025 DBIR). Follow a fixed sequence so you don't tip off the attacker or re-expose new passwords. The single most important rule: clean first, change credentials last. A password reset on a still-infected device is captured the moment you type it, which is a common reason people report passwords leaking again and again.
- 1. If indicators are strong, disconnect the device from the network to stop further exfiltration.
- 2. Review installed browser extensions and remove anything you didn't deliberately add.
- 3. Check persistence: startup apps, scheduled tasks and run keys, where stealers reattach.
- 4. Review recent downloads and cracked or pirated software, a top infection route.
- 5. Run an offline (boot-time) antivirus scan so malware can't hide behind the running OS.
- 6. Verify your accounts and active sessions from a separate, known-clean device.
- 7. For a confirmed infection, back up data and do a clean reinstall.
- 8. Only after the device is clean, rotate passwords and revoke sessions everywhere.
How do I run an offline scan?
An offline scan runs from a trusted environment that boots before the operating system, so malware that hides from the running OS can't protect itself. On Windows, Microsoft Defender Offline restarts the machine and scans for about 15 minutes outside the normal session (Microsoft). Run it in addition to, not instead of, a normal full scan.
Pair the scan with a look at what the stealer targets. Infostealers pull secrets straight from credential stores, the technique catalogued as Credentials from Password Stores (MITRE ATT&CK T1555). If a scan flags browser-data theft or unfamiliar persistence, treat the device as compromised and move to a clean reinstall rather than a spot fix.
How did the infostealer get on the computer?
Most infections trace back to something the user ran: cracked or pirated software, a fake installer or update, a malicious ad, or a phishing attachment. Email remains a primary channel, and IBM X-Force logged an 84% rise in emails delivering infostealers in 2024 (IBM X-Force). Knowing the entry point tells you what else to check and what to warn other users about.
Two patterns dominate. The first is fake software: a search result or ad promises a free tool, a game cheat or a cracked app, and the download carries the stealer. The second is social engineering: a message pushes you to run a command, open a document, or paste something into a terminal. If you installed anything unusual in the days before the symptoms started, treat that as the likely source and check where you got it.
- Cracked, pirated or 'free premium' software, the single most common route
- Fake browser, video-codec or software updates pushed by a malicious page
- Phishing attachments and links, still a top delivery channel
- Malvertising: a poisoned ad or search result above the real download
- Fake CAPTCHA or 'paste this to verify' prompts that run a command for you
What should I do after I confirm an infection?
Once an infection is confirmed, assume everything the browser held is exposed: saved passwords, autofill, and active session cookies. For a clean result, back up your files, do a full reinstall of the operating system, and only then start rotating credentials from the clean machine. A stolen session cookie survives a password change, so revoke active sessions on each important account as you go (SpyCloud 2025).
The hard part is knowing which accounts actually leaked, because a device scan tells you the machine was hit, not which corporate logins are now for sale. Ashetrace matches infostealer logs against a domain, so a security team can see which employee identities and sessions are exposed and revoke exactly those, instead of forcing a blind reset across the whole company.
How do I check my computer for an infostealer?
Isolate the device if signs are strong, review browser extensions and startup persistence, then run an offline scan that boots before Windows so hidden malware can't protect itself. Verify accounts from a separate clean device. Flashpoint tracked 11.1 million infected devices in 2025, so treat unexplained credential leaks as a real prompt to check.
Will a normal antivirus scan detect an infostealer?
Sometimes, but not reliably. Many infostealers run once, exfiltrate, and exit, so nothing persists for an on-demand scan to find. An offline scan that boots outside the running OS is more thorough. Microsoft Defender Offline restarts the machine and scans for about 15 minutes, catching malware that hides from the live session.
Should I change my passwords right away?
No, clean the device first. A password typed on an infected machine is stolen again immediately, which is why people report passwords leaking repeatedly. Remove the infection or reinstall the operating system, then rotate credentials from a clean device and revoke active sessions, since stolen cookies survive a password change.
Can an infostealer hide with no symptoms?
Yes. Infostealers are designed to be quiet: they copy saved logins and the cookie store, exfiltrate, and often delete themselves. The damage persists as valid stolen credentials, not as a visibly infected computer. Verizon's 2025 DBIR found stolen credentials were the top initial-access action in 22% of breaches, often with no obvious host symptom.
Do I need to reinstall Windows after an infostealer?
For a confirmed infection, a clean reinstall is the most reliable fix, because stealers can drop persistence you may miss. Back up your files first, reinstall the operating system, then rotate credentials from the clean machine. If you only suspect infection, a thorough offline scan and persistence review may be enough before deciding.
- Flashpoint, The Proactive Defender's Guide to Infostealers (2025)
- Microsoft, Help protect my PC with Microsoft Defender Offline (2025)
- MITRE ATT&CK, Credentials from Password Stores (T1555) (2025)
- Verizon, 2025 Data Breach Investigations Report (DBIR) (2025)
- SpyCloud, 2025 Annual Identity Exposure Report (2025)
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