crypt888

[Content by Gemini 2.5]

Technical Breakdown – Crypt888 (a.k.a. « Locky-Offline », « MircOp »)

1. File Extension & Renaming Patterns

  • Confirmation of File Extension
    Crypt888 renames encrypted files by pre-pending the static string Lock. to the original file-name while keeping its original extension intact (ex: Budget-2024.xlsx becomes Lock.Budget-2024.xlsx). Unlike most families, it does NOT add a second file extension such as .crypt888, .locky, or .vvv. This is an important visual clue when trying to identify the family.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period
  • First known signature hit: late April 2016 (initially miscatalogued as a generic crypto-threat).
  • Peak propagation wave: June–August 2016 via spam campaigns. Later minor spikes observed in Q2 2017 when Polish operators started rebranding it for local targets.

3. Primary Attack Vectors

  • Propagation Mechanisms
  1. MalSpam – Word or JS attachments claiming to be unpaid invoices (subject #INVOICE-12345) that leverage VBA macros or JS downloaders (.wsf, .vbs, .hta).
  2. SMB / RDP brute-force & lateral movement – Uses weak credentials to pivot from an initial workstation to mapped network shares (older versions relied on SMBv1 but rarely exploit EternalBlue).
  3. Drive-by downloads – Compromised Polish and Russian “warez” forums with malicious TDS redirecting to RIG exploit kit (briefly seen in 2017).
  4. Manual remote intrusion – Attacks against poorly secured RDP ports (port 3389) observed later in the campaign chain (2018).

Remediation & Recovery Strategies

1. Prevention

  • Initial Checkpoint (Block before infection)
  • Disable SMBv1 if not required (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
  • Enforce strong RDP policies: two-factor authentication, Network Level Authentication (NLA), account lockouts (5 failed logins = 30 min lockout).
  • Deploy macro-blocking GPO for Office 2016+: disable all macro execution except for signed whitelisted macros.
  • Patch CVE-2017-0199, CVE-2017-11882 (Office RTF bugs common in early Crypt888 spam).
  • Maintain current offline/backups (3-2-1 rule). Crypt888 kills Windows Shadow Copies (vssadmin delete shadows /all /quiet), so do not rely purely on VSS.

2. Removal – Step-by-Step Cleanup

  1. Disconnect the host from network immediately (pull cable / disable Wi-Fi).
  2. Power-off the machine only if crippled or boot looping; otherwise keep it live to collect logs.
  3. Boot into Safe Mode with networking disabled → log in as local admin.
  4. Install and run vendor or Microsoft Defender Offline scan already on the system OR create an up-to-date rescue USB with:
  • Malwarebytes 4.x
  • Kaspersky Rescue Disk
  • Trend Micro Ransomware File Decryptor (theoretic, but validated for Crypt888 since 2016).
    Delete any files located in:
  • %UserProfile%\AppData\Roaming\[random-num]\ that contain svchost.exe, mshta.exe or explorer.exe impostors.
  • Registry persistence at: HKCU\Software\Microsoft\Windows\CurrentVersion\Run → CryptExecuter or dataup values.
  1. Re-scan with VSSRepair.ps1 or vssadmin resize shadowstorage if you want to resurrect Previous Versions (works only after full malware removal).

3. File Decryption & Recovery

  • Recovery Feasibility
    ✅ YES – Files encrypted by Crypt888 can be decrypted 100 % offline because:
    a. The key-pair is stored inside the malware dropper (hard-coded AES-256 + RSA-1024).
    b. The author leaked or reused an older decryption tool (“Locky Offline Decryptor”) that survived in crowd-sourced archives.
  • Essential Tools / Patches
  • Kaspersky Lab « RakhniDecryptor » (build July 2016+) contains a dedicated Crypt888/’Locky Offline’ module (--crypt888 switch).
  • ESET 888Decryptor tool (GUI-based link: https://decrypt.888.cz/).
  • Alternatively, run StupidDecrypter (Python script v2.3) with command:

    python StupidDecrypter.py --mode Crypt888 --path \\?\C:\Data
  • Make sure to download the tool on a clean machine, checksum-verify (SHA-256: c7c6b…e6f), copy via USB.

4. Other Critical Information

  • Unique Characteristics

  • Crypt888 masquerades as the contemporaneous Locky ransomware, re-using similar ransom note layout (_READ_ME-[random]_.txt) to mislead victims and investigators.

  • It adds an alternative desktop wallpaper depicting a red “YOU ARE LOCKED” logo with skull and crossbones (a GIF placed in %SystemRoot%\Temp\888.gif).

  • C2 communication is uncommon – because the encryption secret is static, functionality remains when the victim is offline, making it extra dangerous in air-gapped networks.

  • Broader Impact

  • Over 20 000 systems were reportedly infected in Poland and the Czech Republic during the 2016 wave, many small businesses never realizing backups were crippled.

  • The group behind Crypt888 (pseudonym 888cry) also experimented with double extortion by threatening to leak data on tele-skype-bot channels, but never released a public leak site—hence it remained under the radar.

  • Timeline overlap with other families – Combating Crypt888 often surfaces remnants of old Vortex / Wallet variants using the same macro lures, so threat hunters should scan for sleeper payloads after cleanup.

TL;DR Cheat-Sheet
Early sign: Files prefixed with Lock. – no new extension.
Git-line defense: Kill SMBv1, macros, weak RDP.
Recovery??? Use Kaspersky / ESET CRYPT888 tool offline. Keep calm, patch, and back-up!