Session fixation across login
A session known to an attacker remains usable after another controlled user authenticates into it.
Candidate CWE: CWE-384
Test hypothesis#
In the local replica, obtain an anonymous session and establish a realistic way to place it in B’s browser. After B logs in, replay the original session from A’s separate client.
Evidence required#
A’s client gains B’s authenticated identity using the previously known identifier. Document the delivery precondition and whether the server rotates or rebinds the credential.
Rule out false positives#
An unchanged analytics cookie or session name, or no feasible method to fix the victim’s session, does not prove account access.
Playbook and command references#
- Authentication, recovery, federation, and session lifecycle — Test registration, recovery, identity changes, invitations, SSO enforcement, and deprovisioning as one account state machine.
Find the associated command snippets
Referenced by these target playbooks#
Report checklist#
- Capture the affected version, configuration, identities, and object ownership.
- Preserve a valid baseline and a negative control.
- Reproduce the forbidden data access, action, or state change on controlled fixtures.
- Explain the intended security rule and why the observed behavior violates it.
- State prerequisites, uncertainty, cleanup, and the smallest demonstrated impact.
Conditional ATT&CK mapping#
- T1550.004 · Use Alternate Authentication Material: Web Session Cookie — Only if: A session cookie acquired across a security boundary is accepted in another controlled client to access the represented user's protected session. Not established by: A missing cookie flag, reflected cookie name, or untested assumption about MFA bypass is insufficient. Ordinary cookie-based login does not demonstrate compromise.