Common authentication attacks are methods used to steal, guess, reuse, or bypass credentials so an attacker can gain unauthorized access to accounts, systems, or data. They include phishing, credential stuffing, brute force attempts, password spraying, session hijacking, and MFA fatigue, each targeting weaknesses in human behavior, secret handling, or identity controls.
What Authentication Attacks Target
Common authentication attacks target the control plane that decides who gets in, so the attacker is usually trying to turn weak sign-in, weak recovery, or reused secrets into usable access. The danger is not only the initial login, but the downstream ability to read data, move laterally, or impersonate a trusted user or service.
These attacks succeed when the defender’s trust model is weaker than the attacker’s access to guesses, stolen secrets, or user interaction. That is why phishing, password spraying, credential stuffing, brute force attempts, MFA fatigue, and session hijacking are often discussed together: they are different paths to the same outcome, unauthorized access.
Common Attack Patterns
Phishing and MFA fatigue rely on human pressure. Phishing tries to capture passwords, one-time codes, or session tokens, while MFA fatigue, sometimes called push bombing, exploits approval prompts until a user accepts one they should have denied. The control failure is often not encryption or protocol design, but human trust and sign-in friction.
Credential stuffing and password spraying are different forms of password abuse. Credential stuffing uses username and password pairs recovered from other breaches, betting that people reuse passwords across services. Password spraying uses a small set of common passwords against many accounts, which can evade lockout controls that are tuned to stop repeated guesses against one account.
Brute force attacks are more direct, repeatedly trying many password combinations against a target. Session hijacking shifts the attack from password guessing to stealing an existing authenticated session, which can bypass the login step entirely if the attacker obtains a valid cookie, token, or browser session.
Why These Attacks Work
Authentication attacks work because authentication is only as strong as the weakest factor in the chain, including password quality, reset processes, recovery workflows, device trust, and session handling. If any one of those pieces is easy to coerce, reuse, intercept, or replay, the attacker can often enter without defeating the whole system.
Modern authentication also creates multiple opportunities for abuse beyond the password itself. Attackers may target help desk resets, legacy accounts without stronger controls, sync gaps between identity systems, or session tokens stolen from browsers, reverse proxies, or compromised endpoints. The result is often a valid sign-in that looks normal unless the organisation is watching for unusual location, device, or behaviour patterns.
What Good Defenses Usually Require
Strong defense starts with phishing-resistant authentication, reduced password dependence, and strict session protection. NIST SP 800-63 Digital Identity Guidelines provides the clearest external baseline for authenticator strength, assurance levels, and phishing-resistant approaches such as FIDO and WebAuthn.
For practitioner detail on rollout and failure modes, MFA Guide explains how attackers bypass weaker MFA methods, and Passwordless and Passkeys Guide shows how passkeys reduce phishing and replay risk when recovery is designed carefully.
Identity programs also need lifecycle discipline, because dormant accounts, old recovery paths, and weak administrative hygiene are frequent entry points. Workforce Identity Security Guide covers the controls that reduce this exposure, including SSO, phishing-resistant MFA, account recovery hardening, and session theft awareness. When session theft is the issue, CitrixBleed exploitation 2023 is a useful reminder that tokens can outlive the password check they were meant to protect.
Detection, Containment, and Recovery
Detection should look for patterns that do not match normal human behaviour, such as many failed attempts across many accounts, repeated MFA push prompts, logins from impossible travel patterns, new device enrolment before access, or sessions that continue after a suspicious reset. For brute force and spraying, the signal is often distributed and low and slow rather than obviously noisy.
Once compromise is suspected, the response focus shifts from blocking one login attempt to revoking what the attacker may already hold, including active sessions, refresh tokens, remembered devices, API keys, and recovery channels. If credential theft or session theft occurred, the account may still be abused even after the password changes, so the compromise review must include sign-in logs, token issuance, and any privileged actions performed during the suspected window.
For external reference on attack pattern and incident response context, CISA cyber threat advisories remains a useful source for active threat guidance, while MITRE ATT&CK Enterprise Matrix helps map credential access, valid account abuse, and session-oriented intrusion techniques into a detection workflow.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
MITRE ATT&CK addresses the attack and risk surface, while NIST SP 800-63 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-63 | 3 — Digital Identity Guidelines | Defines authenticator assurance and phishing-resistant sign-in for authentication attacks |
| Recommendation — Use phishing-resistant authenticators and assurance levels to reduce credential theft and replay risk. | ||
| NIST SP 800-53 Rev 5 | IA-2 — Identification and Authentication (Organizational Users) | Covers strong user authentication for account access protection |
| IA-5 — Authenticator Management | Addresses password, token, and credential lifecycle weaknesses exploited by attackers | |
| Recommendation — Enforce strong user authentication and monitor for abnormal sign-in behavior. Harden authenticator lifecycle controls and rotate compromised secrets promptly. | ||
| MITRE ATT&CK | T1110 — Brute Force | Directly describes password guessing, spraying, and stuffing behavior |
| T1078 — Valid Accounts | Covers use of stolen or abused credentials for unauthorized access | |
| Recommendation — Detect and rate-limit repeated authentication attempts across accounts and services. Alert on valid-account use that deviates from normal user, device, or location patterns. | ||
Related resources from NHI Mgmt Group
- Why do password spraying attacks evade common lockout controls?
- How can organisations reduce the risk of authentication downgrade attacks?
- Why do AI-driven phishing attacks make passwordless authentication more important?
- Why do AI-driven phishing attacks still succeed when organisations use modern authentication?