We required MFA. One query parameter turned it off.
📰 Dev.to · authagonal
Learn how a simple query parameter can bypass MFA and understand why MFA is a session property, not just a login step
Action Steps
- Implement MFA as a session property, not just a login step
- Validate MFA at every token endpoint
- Test authentication systems for potential bypasses
- Use secure protocols for token issuance and validation
- Regularly review and update authentication systems for security vulnerabilities
Who Needs to Know This
Developers and security teams can benefit from this lesson to ensure the security of their authentication systems
Key Insight
💡 MFA is a property of the session, not just a step in the login process
Share This
🚨 MFA bypassed with a single query parameter! 🚨 Ensure MFA is a session property, not just a login step #security #MFA
Key Takeaways
Learn how a simple query parameter can bypass MFA and understand why MFA is a session property, not just a login step
Full Article
We challenged the second factor on the login page and never re-checked it at the token endpoint. So a valid password plus a hand-edited return URL walked straight past MFA. The fix, and the rule it taught us: MFA is a property of the session you issue, not a step in the login screen.
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