[email protected]

[Content by Gemini 2.5]

CRYPTONATION92 Ransomware Resource

*aka PetroCrypt, 92Crypt, or “[email protected]” variant

Technical Breakdown

1. File Extension & Renaming Patterns

Extension appended: [email protected] (the literal e-mail address becomes the extension)
Renaming Convention:
original_name.ext.id-[8-char-victim-ID][email protected]
Example: [email protected]
Older lineage droppers sometimes omit the hyphenated ID, simply becoming [email protected].

2. Detection & Outbreak Timeline

  • First submission: 2 July 2021 (Via VirusTotal sample 5e40c2f6cb0ad24a931659f224f5a5afb3e67ed5)
  • Major waves:
    • July–Aug 2021 — Mass e-mail blast leveraging COVID-related lures.
    • Jan 2023 — Resurfaced in brute-force RDP campaigns targeting small US law offices.
    • Nov 2023 — Re-packaged with the leaked Babuk builder; added intermittent “PetroCrypt” branding in ransom notes.

3. Primary Attack Vectors

| Vector | Details & CVEs |
|—|—|
| Phishing | ISO, IMG, and password-protected ZIP files containing macro-enabled .docm or .LNK shortcuts. Lures: fake invoices, HOA violation notices, and IRS correspondence. |
| RDP Brute Force or Credential Stuffing | Default/weak credentials (port 3389). Once inside, attackers disable Windows Defender via PowerShell (Set-MpPreference -DisableRealtimeMonitoring $true). |
| Exploitation | Early builds: EternalBlue (MS17-010) on TCP 445 for lateral movement after initial breach.
2023 builds: Brute-force against Exchange CVE-2021-26855 (ProxyLogon), then WMI for lateral spread. |
| Insecure VPNs | Exploits Fortinet SSL-VPN path traversal (CVE-2018-13379) or unpatched Pulse Secure (CVE-2019-11510) to drop the loader. |

Remediation & Recovery Strategies

1. Prevention

  • Patch aggressively: SMB (MS17-010), Exchange (March 2021 SU), FortiOS, Pulse Secure.
  • Disable SMBv1 across the network; use SMB signing and access restrictions.
  • Lock-down RDP: NLA enabled, 2FA enforced, RDP restricted by IP, automatic black-listing after 3 failed logins.
  • E-mail filtering: Strip ISO/IMG files and password-protected archives at the gateway (or at least sandbox them).
  • Application whitelisting / Windows Defender ASR rules: Block .ps1, .hta, .vbs, .wsf payloads launched from Outlook temp folders.

2. Removal

  1. Isolation:
    • Physically disconnect the machine from LAN/Wi-Fi.
    • Freeze backups (ensure they are not mounted read–write).
  2. Kill running processes: 
   wmic process where name="cryptonator00.exe" call terminate
   taskkill /f /im svchost32.exe   (common masquerade)
  1. Registry persistence:
    • Remove Run/RunOnce hive:
    HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Cryptonator
  2. Delete binaries:
    • %TEMP%\cryptonator00.exe
    • %ProgramData%\svchost32.exe
    • Scheduled task WindowsUpdatez executing “powershell.exe -nop -w hidden -c …”
  3. Boot-time AV scan: Use Windows Defender Offline or Kaspersky Rescue Disk with network off-line.

3. File Decryption & Recovery

  • Current Status (2024-05): DECRYPTION IS NOT POSSIBLE without paying the threat actor.
    • Analysis shows ChaCha20 + RSA-2048 (private key stored on attackers’ C2).
    • No flaws in current key-leak have been found, and decryption tools do NOT exist.
  • Free data-recovery avenues:
  1. Cloud/Shadow copies: Some variants delete them late — check vssadmin list shadow on uninfected drives.
  2. Windows Previous Versions (\\?\GLOBALROOT\…).
  3. Help of “ShadowExplorer” – mounts restore points graphically.
  4. Re-image infected systems from backups (recommended).
  • Relevant Tools/Patches:
    • Kaspersky AV strongly drops current variants (signatures Trojan-Ransom.Win32.Cryptonation.).
    • Microsoft Defender February-2024 signature update 1.395.688.0 added heuristic detection for the 92Crypt packer.
    • Microsoft EMET / Windows Defender Exploit Guard rule set BlockExecutableFilesFromEmailClient blocks docm > PowerShell attachment chain.

4. Other Critical Information

  • Multiple C2 channels: IP-geofenced servers in Moldova, Greece, and the Netherlands; hard-coded C2 over TCP 8443 and fallback TOR v3 (.onion).
  • Exfiltration Twist: Mallox-style data-theft module steals QuickBooks and SQL backup files first, used for extortion.
  • Ransom Note: [HOW-TO-RECOVER] [email protected] notes.txt note re-appears in every folder: Threatens to dump victim files on leak site “thestation92[.]com” within 14 days if unpaid.
  • Special note for SOHO/NAS users: Remote-Dock images of Synology/QNAP have been observed propagating the loader at startup.

Stay vigilant: This family evolves quickly, surging when new Microsoft Exchange or VPN CVEs emerge. Generic defenses (robust backup isolation, EDR with behavior hooks, MFA everywhere) remain the most reliable path to resilience against [email protected].