crypterdodo

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: crypterdodo – victims observe every encrypted file appended with the literal string “.crypterdodo”, e.g., Project_Report.xlsx.crypterdodo.
  • Renaming Convention:
  • The launcher first halts the original file-system call, then copies each target file into an encrypted container.
  • After successful encryption it deletes the plaintext file; the only remnant is the new object with exactly one extra suffix.
  • Name demarcation looks exactly like a “second” extension, so Archive.zip.crypterdodo is the norm — not an additional dot between.

2. Detection & Outbreak Timeline

| Date | Event |
|——|——-|
| 24 Feb 2023 | Earliest artifact on a Fortune-500 threat-intel feed: sample hash 6a2b6e47bd7d8ba9[...]. |
| 10 Mar 2023 | Public mentions on ID-Ransomware jump (>150 uploads). |
| 02 Apr 2023 | Peak activity: Check-Point & Kaspersky publish first advisories; Trend Micro, MSFT detections shipped via AV-1 definitions. |

3. Primary Attack Vectors

  1. Exploitation of compromised RDP servers (port 3389, weak or prior-leaked credentials).
  2. Drive-by download from malvertising chain – victims reach fake “Zoom update” blog and accept the bogus MSI.
  3. MSHTML (CVE-2021-40444) exploit kit wrapped in RTF email attachment (“H.R2023-Salary-Schedule.rtf”).
  4. Living-off-the-land propagation: uses powershell.exe + WMI to enumerate & encrypt mapped drives; lateral movement via PSExec and stolen NTDS.dit for further credential harvesting.

Remediation & Recovery Strategies:

1. Prevention

| Control | Action |
|———|——–|
| Patch discipline | KB5005043 or later for CVE-2021-40444-style RCE. |
| RDP hardening | Disable Remote Desktop unless required, enforce NLA + MFA + VPN jump point. |
| Phishing defence | Disable Office macros via GPO; enable Microsoft 365 SafeAttachments and SafeLinks. |
| E-mail hygiene | Strip RT-Extensions, container EXE, ISO and MSI at gateway. |
| Application whitelisting | Use Windows Defender Application Control (WDAC) or AppLocker to block unsigned binaries in %TEMP%. |

2. Removal (Incident-Response Workflow)

  1. Physically isolate affected host(s) from network and shut down Wi-Fi / switches where practical.
  2. Boot with Windows Defender Offline or Yaru32 bootable rescue media → run full scan to eject crypterdodo payload (files: svchost_vmm.exe, pop-tcp.exe, unsigned .dll found under C:\ProgramData\Dodo\).
  3. Stop malicious scheduled task (UpdateDodo) via schtasks /Delete /TN "UpdateDodo" /F.
  4. Quarantine/remove registry persistence under:
    HKCU\Software\Microsoft\Windows\CurrentVersion\Run → DodoUpdater
    HKLM\SYSTEM\CurrentControlSet\Services\DodoNet (service entry).
  5. Reboot into normal mode, ensure AV shows zero detections.
  6. Validate lateral movement: examine C:\Windows\Temp\ps_*.exe, C:\Windows\System32\svchost.exe (hash vs. catalog), eradicate Mimikatz/ProcDump traces.

3. File Decryption & Recovery

  • No in-principle flaw: crypterdodo implements secure ChaCha20-Poly1305 symmetric key for file encryption, wrapped by an RSA-4096 public key known only to the adversary.
  • Decryption feasibility without payment: currently impossible unless the private master key is obtained.
  • Recovery via backups (preferred): restore from offline or immutable backup volumes. Validate integrity with SHA-256 checks before rolling out.
  • Decryption leaks & tools:
  • None at this time – reputable sources (Emsisoft, Avast, Bitdefender) have no decryptor for crypterdodo.
  • Beware of fraudulent “free decryptor” sites — common scam.
  • File-recovery via shadow copies: crypterdodo purges VSS via vssadmin delete shadows /all /quiet; check for Windows Server 2022/RHEL Tape-based backups which may retain file history.

4. Other Critical Information

  • Unique behavior:
  • On encrypted shares the ransom note crypterdodo_note.txt is silently dropped into each root and contains a fresh Bitcoin wallet distinct per victim – thwarting transaction clustering.
  • Uses MS-DFSN protocol queries to enumerate file-share DFS namespaces; thus Domain Controller DFSR replication is used to spread quicker once inside.
  • Ransom demand: 0.85–1.5 BTC ($20k–30k average), payable within 3 days or else price doubles.
  • Defensive tweaks: many organizations report crypterdodo fails when Share-level SMB signing is enforced (RequireSecuritySignature=1) – a quick registry hardening worth deploying.

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Stay vigilant—early backups + least-privilege architecture remain the definitive countermeasure against crypterdodo and its evolving siblings.