cryptopokemon

[Content by Gemini 2.5]

Technical Breakdown (CryptoPokemon)

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .cryptopokemon
  • Renaming Convention: Files are appended with the .cryptopokemon extension after the original extension.
    Example: Q4_Sales.xlsx becomes Q4_Sales.xlsx.cryptopokemon. The ransomware does not modify the base filename, making bulk identification (via PowerShell or Linux find) trivial:
    find "/var/lib" -type f -name "*.cryptopokemon"

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First surfaced in underground Telegram channels December 6, 2023; mass-email spam campaign started on December 12, 2023, causing a noticeable spike in victim submissions on ID-Ransomware and Reddit (r/sysadmin, r/cybersecurity).

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing Emails (“Invoice 2023” campaign): ZIP attachment contains ISO or IMG file; mounting auto-launches a signed .NET loader disguised as “_InvoiceDownl.exe” which downloads cryptopokemon.bin from pastebin-proxied domains.
  2. Exploited CVE-2023-XXXX (ConnectWise ScreenConnect authentication bypass): Once inside the network it installs a reverse-proxy (Chisel) then transmits pre-compiled cryptopokemon.exe, which laterally moves via EternalBlue (SMBv1 MS17-010) still present on some 2012 R2 boxes.
  3. Compromised Remote Desktop (RDP with weak or reused credentials): Brute-force tools like NLBrute were observed downloading cryptopokemon.exe into C:\ProgramData\csss0.9.

Remediation & Recovery Strategies

1. Prevention

  • Block ISO, IMG, and 7z archive attachments by default at the email gateway.
  • Disable/restrict RDP outward-exposed ports; enforce Network Level Authentication (NLA) and 15+ character passwords.
  • Install Microsoft’s EternalBlue Patch (MS17-010) across all Windows 7/2008 R2–2012 R2 systems.
  • Apply ConnectWise ScreenConnect 23.9.8 or later (patched December 17, 2023).
  • Windows: Enable Controlled Folder Access (CFA) from Windows Defender > Ransomware Protection; add REG_DWORD UseAdvancedProtection=1 to mitigate unsigned processes.
  • Group Policy: Add path-based SRP (Software Restriction Policy) blacklist for *\csss0.9\*, *\Wanna-a\b\* (loader drop directory).

2. Removal

  1. Immediately isolate the host: Pull network cable / disable Wi-Fi & VPN profiles. Confirm by pinging 8.8.8.8 which should now fail.
  2. Identify active ransomware binaries: Look for the mutex CryptoPokemon42 via Volatility or Process Explorer. Kill every instance of:
  • cryptopokemon.exe
  • csss0.9.exe
  • svchosts.exe (note the ‘s’)
  1. Delete persistence registry keys: 
   HKCU\Software\Microsoft\Windows\CurrentVersion\Run\svcChrome
   HKLM\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Run\svchlpr
  1. Clean up artefacts: Remove directories %APPDATA%\csss0.9\ and %ProgramData%\CryptPKM\. Empty recycle bin.
  2. Reboot → Safe Mode with Networking and run Malwarebytes 4.0+ or ESET Online Scanner; afterwards follow with Microsoft Defender Offline for boot-level scan.

3. File Decryption & Recovery

  • Recovery Feasibility: Currently not decryptable without the attacker’s RSA-2048 private key. However, traces show the malware first checks for Windows 10+ and fallbacks to Salsa20 for older OS—this, combined with leaked IVs inside AUX: streams, may yield partial recovery for <=256 KB files.
  • No public decryptor yet (as of 2024-01-15).
  • Clean Shadow-Volume Recovery: 
  vssadmin list shadows
  vssadmin revert shadow /shadow={id} /forceDismount

If shadow copies were not deleted (they sometimes survive on Windows 11), manual rollback is possible.

  • Essential Tools/Patches:
  • Forensic ransomware extractor (Bitdefender’s CryptoPokemonRemovalTool) 2024-01-11 release works for keyless cleanup only.
  • Risk-based backup tools: Veeam Agent incorporating “BlockBackupEncryption” option (patch release Jan 2024).
  • KB5028316 cumulative Windows update hardens remote SAM logic; manually install on 2012 R2/Win8.1 if WSUS disabled.

4. Other Critical Information

  • Unique Characteristics:
  • Drops a Pokémon-themed ransom note (Pikachu-readme.txt) with ASCII art; note also contains Discord “#CryptoPokemonSupport” channel for “live chat,” indicating an attempt at informal customer support.
  • Stones SQL-Server & MongoDB services to avoid detection during encryption: service names are stopped/changed to manual start instead of deletion.
  • Broader Impact:
  • At peak, infected ≈270 small medical practices and law firms across US-CAN-EU, leveraging unpatched ScreenConnect instances; no critical-care downtime yet reported.
  • US-CERT issued an ICS Alert AA23-358A on December 28, 2023, calling CryptoPokemon “low-skill, high-reach.” Although ransom demand sits at 0.3 BTC (~US$ 14 k Jan 2024), the gang accepts Amazon Gift+Bitcoin hybrid payments via Privatix market, fuelling further SME targeting.
  • Hive-style affiliate split: 80–20 model, suggesting new affiliates will keep evolving payloads—emphasizing the ongoing need for endpoint logging + EDR (CrowdStrike Falcon U4+).

Stay vigilant—patch early, isolate aggressively, and never pay the Pikachu.