| Term | What it is | CISSP Trap |
|---|
| TOCTOU | Attacker exploits window between permission check and resource use | NOT a covert channel — it's an implementation vulnerability |
| Race Condition | Two threads compete for a shared resource; outcome depends on timing | Root cause of TOCTOU |
| Deadlock | Two threads each hold a resource the other needs — neither proceeds | Availability failure, not confidentiality |
| Starvation | A thread is perpetually denied resources by higher-priority threads | Also an availability issue |
| Mutex | Only ONE thread may access the resource at a time (binary lock) | Fix for race conditions |
| Semaphore | Controls access for up to N concurrent threads (counting signal) | More flexible than mutex; not binary |
| Atomic Operation | Executes as one indivisible unit — no thread can interrupt mid-execution | Strongest guarantee; eliminates race windows |
| Covert Timing Channel | Leaking data by varying response time (e.g., cache hit vs miss) | Sutherland model — different from TOCTOU |