Session hijacking
Taking over an authenticated session by stealing or predicting its identifier, through XSS, network interception, malware, logs or a leaked URL, and presenting it as the victim (CAPEC-593). Protect session cookies with Secure, HttpOnly and SameSite, rotate identifiers and require reauthentication for sensitive actions.
- Defined in
- MITRE CAPEC-593: Session Hijacking
Covered in
Session management: cookies, timeouts, rotation and revocation
Model authentication as transitions in server authority, set session cookies and timeouts to current NIST and OWASP values, and verify fixation prevention, expiry, reauthentication, revocation and stolen-cookie defenses.
Case study: Citrix Bleed (CVE-2023-4966)
How a NetScaler memory over-read leaked session cookies that bypassed passwords and MFA in 2023, why patching did not end hijacked sessions, and how the pattern returned in 2025.
Case study: the Okta support-system breach and session tokens in HAR files (2023)
How a service account password saved to a personal browser profile let an attacker download customers' HAR files from Okta's support system, replay the session tokens inside them against five customers, and stay unseen for two weeks; and why HAR files are credentials, admin sessions need binding, and every exposed credential must be rotated.
Case study: the CircleCI security incident (January 2023)
How a session stolen from one engineer's laptop reached CircleCI's production systems and customers' stored secrets in 2023, and what platform operators and CI users should change.