Category: Account & Session Attacks
Credential stuffing in the browser
Credential stuffing is when attackers use leaked username/password pairs to automatically try logins across many sites until one works.
Quick answer
It turns unrelated breaches into new compromises, especially when employees reuse passwords across work and personal accounts.
For token theft and session hijacking patterns, isolation reduces exposure by separating web execution from the endpoint and limiting session residue when the container is deleted.
When you need this
- You’ve seen indicators of this threat in your environment.
- Users frequently click unknown links as part of daily work.
- You need a control that reduces risk without relying on perfect user judgment.
Last updated
2026-01-29
How it usually happens in the browser
- Attackers obtain large credential dumps from previous breaches.
- They automate login attempts against SaaS apps and identity portals.
- Successful logins are used to steal data, create persistence, and phish internally.
- Browsers become part of the flow when victims are prompted into “verify/login” actions and attackers use session tokens post-auth.
What traditional defenses miss
- Rate limiting and bot detection aren’t always configured strongly across all apps.
- Users continue to reuse passwords and underestimate the risk of past breaches.
- MFA helps, but attackers can still harvest sessions through related techniques if users are lured to malicious pages.
How isolation changes the game
- Isolation reduces exposure to the phishing and social engineering steps that often follow credential-stuffing discovery (verification prompts, fake resets).
- Policy can route unknown destinations into isolation so “account verification” lures don’t run directly on endpoints.
- Isolation complements identity controls like SSO, MFA, and strong password hygiene.
Operational checklist
- Enforce SSO and MFA for critical apps; prefer phishing-resistant MFA for admins.
- Use password managers and prohibit password reuse for work accounts.
- Enable bot detection, rate limiting, and suspicious login alerts across identity providers.
- Isolate untrusted browsing paths to reduce follow-on phishing and malware delivery.
- Monitor for account takeover signals after successful stuffing (new inbox rules, API keys, OAuth grants).
FAQs
Is credential stuffing the same as brute force?
Not exactly. Brute force guesses passwords. Credential stuffing uses known leaked credentials and tests them at scale.
Does MFA stop credential stuffing?
It helps significantly, but you still need bot defenses and good password hygiene to reduce noise and prevent partial compromise.
What’s the fastest mitigation?
Enforce SSO + MFA and require strong unique passwords via a manager. Then tune bot protections and alerts.
How does isolation relate?
Isolation reduces risk from the browser-based follow-on steps attackers use after they find working credentials—like phishing for MFA bypass or stealing sessions.