How to Use the LockCrypt Ransomware Decryption Tool (Step‑by‑Step)
Note: LockCrypt has multiple variants. The most widely available decryptors (from Bitdefender / Unit42 analyses) target specific sub‑variants (e.g., files ending in .1btc). This guide assumes you have the correct decryptor for your LockCrypt variant.
Before you begin (precautions)
- Isolate infected machines: Disconnect from networks and unplug external drives to prevent spread.
- Work on copies: Do not run the decryptor on original encrypted files. Make full disk or file-level backups (copy encrypted files to an external drive) first.
- Identify variant: Confirm file extensions (e.g., .1btc, .lock, .2018). Only some extensions may be supported by a given tool.
- Collect ransom notes & samples: Save one or two encrypted files and the ransom note files (ReadMe.txt / Restore Files.txt) for diagnostics.
Step 1 — Obtain the official decryptor
- Use a trusted vendor: download the LockCrypt decryptor from a reputable security vendor (examples historically: Bitdefender, Unit42/Palo Alto Networks, or Emsisoft). Do not download from forums or unknown sites.
- Verify file integrity (virus scan) before running.
Step 2 — Prepare the system and tool
- Boot into a safe environment if recommended by vendor (some tools require normal Windows; others can run from PE/rescue media).
- Ensure you run the decryptor with Administrator privileges (right‑click → Run as administrator on Windows).
- If the vendor tool offers an offline mode, prefer that while the machine is isolated.
Step 3 — Configure options in the decryptor UI
Most vendor decryptors use a similar workflow:
- Accept EULA and any prompts.
- Select folders or drive(s) to scan:
- Option A: Scan entire system (recommended if you don’t know all affected locations).
- Option B: Add specific folder(s) containing encrypted files (faster).
- Enable “Backup files” if the option exists (creates copies before decryption).
- Select log / output location if configurable (useful for troubleshooting).
Step 4 — Run a test on a small sample
- Choose 1–5 small encrypted files (non‑critical) and attempt decryption first.
- Verify successful decryption and that original data integrity looks correct. If files are corrupted or remain encrypted, stop and consult vendor support or logs.
Step 5 — Full decryption run
- Start the main scan/decryption.
- Monitor progress; decryption speed depends on file sizes and CPU. Tools will typically show files decrypted, skipped, or failed.
- If the tool requires known‑plaintext or additional steps (some LockCrypt analyses require recovering keys with known plaintext and running scripts), follow vendor instructions exactly:
- Acquire a matching original file (e.g., same DLL from a clean install) of sufficient size if requested.
- Use provided scripts (Python/SageMath) only on an offline, secured machine and follow the vendor’s step sequence to recover keys, then run the decryptor.
Step 6 — Review results and logs
- Inspect the tool’s log (often saved to %temp% or a folder the tool shows).
- Confirm critical files are restored and open properly.
- If some files failed, check if those files belong to an unsupported LockCrypt variant or are partially corrupted.
Step 7 — Clean up and restore operations
- Remove ransomware artifacts: follow vendor removal instructions or run a full anti‑malware scan to ensure the infection is removed.
- Replace infected systems from clean backups if necessary.
- Reconnect to the network only after you’re sure malware is removed.
- Restore any files from backups for files that couldn’t be decrypted.
When decryption fails
- Confirm you used the correct decryptor for the extension/variant.
- Check vendor FAQs or contact their support and attach the decryptor log.
- If vendor tools require advanced recovery (key recovery via scripts), consider engaging a professional incident responder.
Practical tips
- Keep originals backed up offline before attempting any automated fixes.
- Document the incident (timestamps, affected systems, sample filenames) for later forensic or insurance needs.
- After recovery, apply security fixes (patch OS/software, change credentials, review RDP exposure) and implement a 3‑2‑1 backup strategy.
Useful vendor resources (examples)
- Bitdefender LockCrypt decryptor page
- Unit 42 analysis and recovery scripts on GitHub
- No More Ransom portal (for aggregated decryptors)
If you want, I can:
- Provide direct vendor links for the decryptor that matches your file extension (tell me the extension, e.g., .1btc).
Leave a Reply