Predictable temporary files and unsafe creation
A component creates or reuses temporary files in a way that permits another local principal to precreate, replace, read, or redirect sensitive operations.
Candidate CWE: CWE-377
Test hypothesis#
In a local multi-user fixture, inspect path selection, creation atomicity, permissions, and link handling. Use an owned synthetic destination and a harmless marker to test precreation or replacement. Establish the attacker's directory permissions and the victim's actual privilege.
Evidence required#
Temporary path construction, creation flags/mode, distinct actor identities, directory permissions, protected synthetic effect, and safe exclusive-creation control. For races, preserve a repeatable bounded sequence and observed success count.
Rule out false positives#
Secure atomic creation in a private directory, restrictive file permissions, caller-owned paths with no privilege difference, or a hypothetical race with no attainable scheduling/permission conditions.
Playbook and command references#
- Source review: entry point to protected operation — Trace attacker control and authorization through handlers, services, queues, and sensitive operations; promote only reachable violations of a stated invariant.
- OSS lab: pin, install, prove, reset — Turn an eligible release into a repeatable synthetic environment with preserved versions, realistic controls, and an explicit reset recipe.
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#
No direct ATT&CK mapping selected. Record the weakness and demonstrated impact without forcing an adversary-behavior classification. See the mapping guide.