Cybersecurity glossary
What are Authentication Failures?
Learn what authentication failures are in the OWASP Top 10, how weak login, session, and credential handling enable account takeover, and how to strengthen authentication.
Definition
Authentication Failures is an OWASP Top 10 category (A07:2021 Identification and Authentication Failures) covering weaknesses in proving and maintaining user identity—weak passwords, credential stuffing exposure, broken session handling, missing MFA, and related flaws that enable account takeover.
Why authentication failures matter
Account takeover turns your product into the attacker’s. Authentication Failures (OWASP A07) cover weak proofs of identity and fragile sessions—still among the most profitable bugs because a single inbox or SaaS account can unlock downstream systems.
Credential stuffing, session theft, and poorly designed recovery flows routinely beat “we have a login page” as a security story.
How authentication failures are exploited
Obtain or guess credentials
Breach corpora, phishing, spraying, or weak default passwords supply login material.
Bypass or weaken checks
Missing rate limits, MFA gaps, verbose login errors, or flawed recovery help the attacker in.
Establish a lasting session
Predictable session IDs, fixation, or cookies without Secure/HttpOnly keep access alive.
Abuse the account
Data theft, fraud, lateral SaaS access, or persistence via new MFA factors and API keys.
Common A07 failure patterns
Credential stuffing
Automated reuse of breached passwords against login APIs without effective bot controls.
Weak session handling
Session fixation, IDs in URLs, missing rotation, and insecure cookie attributes.
MFA gaps
Optional MFA, skippable enrollment, or recovery that resets to password-only.
Unsafe recovery
Predictable reset tokens, account enumeration, and sessions that survive password change.
Strengthening authentication
| Control | Notes |
|---|---|
| Strong password policy | Length, breach checks, and resistance to common passwords over complex rituals |
| MFA / passkeys | Prefer phishing-resistant factors for sensitive accounts and admins |
| Bot and stuffing defenses | Rate limits, device signals, and credential stuffing detection on login |
| Secure sessions | Rotate on login; Secure, HttpOnly, SameSite cookies; short idle timeouts |
| Safe recovery | Single-use tokens, tight TTL, and invalidate sessions after credential change |
| Monitor auth events | Alert on impossible travel, stuffing spikes, and MFA fatigue patterns |
- Block known-breached passwords and enforce sensible length minimums.
- Add rate limiting and stuffing detection on authentication endpoints.
- Require MFA for privileged roles; encourage passkeys where feasible.
- Regenerate session identifiers after login and privilege changes.
- Set Secure, HttpOnly, and appropriate SameSite on session cookies.
- Harden password reset and magic-link flows against enumeration and replay.
- Invalidate sessions and refresh tokens after password or MFA changes.
- Review 'remember me', OAuth callbacks, and API key issuance for A07 gaps.
The practical takeaway
Authentication Failures (OWASP A07) let attackers become your users. Combine strong credentials, MFA, stuffing defenses, and secure session/recovery design—and treat broken authentication and credential stuffing as first-class test targets.
Related security terms
Broken Authentication
Classic framing of authN flaws that overlap heavily with OWASP A07.
Credential Stuffing
Automated login attempts using breached username/password pairs.
Brute Force Attack
Systematic guessing against passwords, tokens, or OTPs.
Adaptive Authentication
Risk-based challenges that strengthen auth under suspicious signals.
Frequently asked questions
What are authentication failures in simple terms?
The system cannot reliably tell who someone is, or cannot keep that proof safe—weak passwords, stuffed credentials, guessable sessions, or MFA that can be skipped.
Is this the same as broken authentication?
Largely yes in practice. OWASP A07 uses 'Identification and Authentication Failures'; many materials still say broken authentication for the same class of issues.
How does credential stuffing fit?
If login lacks bot defenses, breach detection, and MFA, attackers replay leaked passwords at scale. That is a primary A07 exploitation path.
Are sessions part of authentication failures?
Yes. Session IDs in URLs, missing regeneration after login, overly long idle lifetimes, and insecure cookie flags undermine authenticated identity.
Does MFA eliminate A07 risk?
MFA greatly reduces password-only takeover but can be bypassed via phishing, SIM swap, fatigue attacks, or flawed recovery flows if those paths are weak.
What should password reset look like?
Unpredictable, single-use, short-lived tokens delivered out of band; no account enumeration side channels; and invalidation of old sessions after reset.
How do teams test authentication?
Probe rate limits, stuffing resistance, session fixation, cookie flags, MFA enrollment/bypass, and recovery flows with both automated and manual abuse cases.
References
Explore authoritative guidance and frameworks related to authentication failures.
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