Parallel execution

[StrongWind1]

What problem does this solve?

Credential testing is currently sequential — each attempt waits for the previous one to complete before starting the next. For large user/password lists, especially over TCP where connection setup dominates, this makes runs unnecessarily slow. A 10,000-user spray with 15-second timeouts on unreachable hosts could take days sequentially.

Proposed solution

Add thread-based or async parallelism with a configurable concurrency level (e.g. --threads N, default 1 for backwards compatibility). Each worker would independently pull user/secret pairs from a shared queue and test them against the target. Results would still be written to output in a thread-safe manner.

Key considerations:

• The --delay and --jitter options should apply per-thread to maintain rate limiting guarantees
• The --max-lockouts consecutive revoked counter needs to be thread-safe (atomic or locked)
• The --stop-on-success flag needs to signal all workers to stop
• Salt caching for Kerberos AES should be shared across threads (one salt fetch per user regardless of thread count)
• Connection failure and clock skew should halt all threads immediately

Alternatives considered

• GNU parallel or xargs -P wrapping multiple credwolf invocations — works but loses salt caching, lockout tracking, and stop-on-success coordination across instances
• asyncio — possible but impacket's socket operations are synchronous, so would require run_in_executor wrappers