Cookie Security Checker

Session cookies are the keys to your users' accounts. A cookie without the HttpOnly flag can be stolen via XSS. A cookie without the Secure flag can be transmitted over HTTP. A cookie without the SameSite flag is vulnerable to CSRF attacks. All three flags should be set on every authentication cookie.

What it checks

  • HttpOnly flag (prevents JavaScript access)
  • Secure flag (HTTPS-only transmission)
  • SameSite attribute (CSRF protection)
  • Cookie prefix (__Secure- and __Host-)
  • Cookie expiry / session vs persistent
  • Path and Domain scope

Why it matters

Session cookies without proper flags are the most common vector for account takeover. HttpOnly prevents cookie theft via XSS; Secure prevents transmission over HTTP; SameSite prevents CSRF. All three take 5 minutes to add.

Common issues found

Missing HttpOnly flag on session cookiesMissing Secure flag (cookie sent over HTTP)Missing SameSite=Lax or Strict (CSRF risk)Overly broad Domain scopePersistent session tokens that never expire

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Free, instant Cookie Security check — no account required