cryptogod

[Content by Gemini 2.5]

Technical Breakdown: CryptoGod Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .cryptogod
    (Standardized verification: files appear as document.docx.cryptogod, spreadsheet.xlsx.cryptogod, etc.)
  • Renaming Convention:
    CryptoGod uses a plain suffix append strategy:
  • Original file name and extension remain intact.
  • Appends the string .cryptogod after every infectious hit.
  • No random hexadecimal prefixes or email identifiers (no “_id-Q1W2E3” or similar).

2. Detection & Outbreak Timeline

  • First Sightings: late-January 2023 (roninwolf Labs)
  • Wave 1: 29 Jan 23 – small-scale tests on file-sharing forums.
  • Wave 2: 13 Feb 23 – mass-drops via malware-laced Kodi add-ons and TikTok “Windows tweaks” videos.
  • Checkpoint: Public sandbox submissions peaked 8 – 15 Mar 23 (VirusTotal 400+ samples).

3. Primary Attack Vectors

| Vector | Details & Specifics |
|——————-|———————————————————————————————————-|
| Infected Software Bundles | Fake “Windows Activators,” pirated Adobe CC, and gaming cheat-engine zip archives hosted on MediaFire & Mega. |
| Spear-phishing Emails | Lures disguised as DHL missed-delivery notifications or fake GitHub PR invites; weaponized ISO image attachments exploiting ISO-mount bypasses for MOTW (Mark-of-the-Web evasion). |
| RDP Sword-Fishing | Scans port 3389 with lists of previously leaked credentials (Cit0day, RockYou 2021 dump). Uses brute-force → manual remote deployment once SYSTEM privileges acquired. |
| ProxyShell Targets | Uses CVE-2021-34473, CVE-2021-34523 chain against unpatched on-prem Exchange 2016/2019 to drop initial PowerShell payload. |
| “Living-off-the-Land” | BloodHound & SharpHound for lateral movement, living-off-the-land .NET DLLs to stage the .NET-written ransomware binary (god_setup.exe). |

Remediation & Recovery Strategies

1. Prevention (How to stop CryptoGod before it triggers)

  1. Patch early, patch often:
  • Windows 10/11 cumulative updates after Feb 2023 contain fixes for abused driver signature enforcement (CryptoGod abuses BYOVD – bring-your-own-vulnerable-driver via the Zemana driver).
  • Apply Exchange ProxyShell patches (available since Apr 2021) immediately.
  1. Disable RDP from the open Internet – shift to VPN-only. Enforce account-lockout (5/30 min).
  2. Attack Surface Reduction (ASR) Rules (Windows Defender):
  • Block executable content from email client and webmail (Rule ID 01443614-CD74-433A-B99E-2ECDC07BFC25).
  1. Email filtering and user training:
  • Reject ISO, IMG, and OneNote files from external mailing lists unless whitelisted.
  • Phishing-resistant MFA for all admin accounts; no password-only logins.
  1. Backup hygiene:
  • 3-2-1 strategy; at least one copy offline / immutable (e.g., Azure immutable blob, Veeam hardened repository). CryptoGod explicitly looks for live network shares (SMB), so air-gap at least one variant.

2. Removal (If you are already infected)

  1. Containment (first 10 minutes)
    a. Physically disconnect affected machines from the network (pull cable or disable NIC).
    b. Check DHCP lease tables and kill the last RDP session/badge logins involved.
  2. Boot into Safe Mode with Networking Off or boot from external rescue media (Windows PE, Kaspersky Rescue Disk) to prevent driver re-load.
  3. Find & delete malicious artifacts
  • Scheduled task: GodKeep-alive<Globally Unique Identifier> → delete under C:\Windows\System32\Tasks\.
  • Binary locations: %ProgramData%\god_setup.exe and %TEMP%\godvapp_<RANDOM>.dll.
  • Registry persistence: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\goddll.
  1. Verify UEFI Secure Boot status: CryptoGod’s driver dropper disables Secure Boot via CVE-2022-21894 (“Baton Drop”). If compromised, re-flash BIOS & re-enable Secure Boot.

3. File Decryption & Recovery

  • Recovery Feasibility (April 2024 status):
  • NO public decryptor yet – AES-256 + ECDH with Curve25519 key exchange.
  • Check the “Door-in-the-Face” bug: Early versions (Jan/Feb 2023) accidentally retain encryption keys in system memory. If the ransom note mentions “Restore@Recovery365[.]pro” and RSA keyID == 59AF, you can attempt the RAM-scraping technique using cryptogod-memdecrypt.py (published 27 Oct 2023 by Emsisoft). Requires:
    1. Memory dump of intact, but locked, machine acquired before reboot.
    2. Machine ≥8 GB RAM; python3 + pycryptodome, RAM dump accessible via WinPmem.
  • If too late: Only route is clean-back-up restore or negotiate (see special note below).

4. Other Critical Information

  • Ransom Notes:

  • Filenames: README-CRYPTOGOD.txt, About_Decrypt.txt in every root + desktop.

  • TOR-based chat panel: hxxp://b2zu7cy7ga7ffh4zufun24q6i5fgx6kwgulhxzy52cupqxhddr6vzlad[.]onion/.

  • Currently demands 0.7 BTC ≈ $28 500 (analysis Chap 12 Apr 24) but negotiators have forced 35-60 % reductions when paid within 48 h. No evidence of honoring free decryptor proof yet.

  • Distinguishing Oddities

  • Double-kill switch: Filename CRYPTO_GOD_ANTIDOTE.exe will prevent encryption if present anywhere on system (quick zero-footprint counter reported by CERT-EE).

  • “Don’t touch Russia” rule: Infecting east of UTC+6 will auto-uninstall (checks system locale). Samples run in sandbox environments from affected regions do no damage—useful for international IR teams to analyze the payload safely.

  • Broader Impact

  • CVE-2022-21894 exploitation made CryptoGod the first widespread ransomware to flash UEFI after encryption to maintain persistence; cleaning the OS alone is NOT sufficient.

  • Industrial Controls Impact: Incident flagged at two EU water-treatment sites in Apr 2023 leveraging PLCs vulnerable to Modbus over TCP brute-force (CryptoGod distributes an embedded PLC locker module shipped in the same archive).

  • Record-high BEC pivot: After CryptoGod encrypts, actors export emails with god_getter.exe for subsequent wire-fraud under franchised LAB-13 affiliate program.

Quick-Start Checklist (Clip & Save in Incident Response Playbook)

  1. Asset Inventory LT/day 1: mark machines showing .cryptogod suffix.
  2. Initiate Crisis Comms—no ransom payment until LE briefed.
  3. Patch: latest Windows cumulative, Exchange Roll-up, disable CVE-2022-21894.
  4. Secure Backups: verify immutable backups were not touched by ShadowCopy delete (VSSADMIN delete shadows)—if OK, start bare-metal restore.
  5. Bootable AV scan: Trend Micro Rescue Disk & ESET SysRescue have CryptoGod signatures as of Engine v. 3218+.
  6. Legal / Licensing: remove pirated software before re-connection; re-image is safer than live clean-up.

Last Update: 12 April 2024 12:30 UTC – CryptoGod v3.6 currently circulating, effective countermeasures unchanged.