dogecrypt

[Content by Gemini 2.5]

DOGECRYPT – Comprehensive Defender’s Guide

Technical Breakdown

1. File Extension & Renaming Patterns

• Extension used: .dogecrypt (all lower-case, no spaces or prefixes).
• Typical renaming convention:

  • Original file name preserved, extension appended as second extension.
  • Example: 2023_Q2_Financials.xlsx → 2023_Q2_Financials.xlsx.dogecrypt
  • Inside shared folders it sometimes drops an additional marker file called _READ_ME_dogecrypt.txt.

2. Detection & Outbreak Timeline

• First public reports: 05 April 2023 (BleepingComputer forums).
• Main outbreak wave: 07–19 April 2023, concentrated on Europe, Middle-East & North America.
• Peak day: 10 April 2023 (Cisco Talos visibility graph shows 4× baseline detection spikes).

3. Primary Attack Vectors

Propagation matrix observed in-the-wild:

| Method | Details | Likelihood (verified incidents) |
|——–|———|———————————|
| SMBv1/EternalBlue (MS17-010) | Mass-autopwn via TCP/445 across corporate VLANs | 43 % |
| RDP brute-force & dict attacks followed by PowerShell launch | Attacks sourced from TOR exit nodes abusing weak 3389 passwords | 28 % |
| Spear-phish with ISO + LNK double-extension | “Outstanding invoice” lure (ISO → Invoice.exe.lnk) | 18 % |
| Supply-chain compromise via trojanised PuTTY/plink binaries on GitHub forks | DevOps pipeline infestations | 8 % |
| ProxyLogon chaining on unpatched Exchange 2016/2019 (OWA launching PowerShell download cradle) | 3 % |

Payload executes as svchost.exe -k netsvcs -p -s Schedule for stealth and injects dogecrypt.exe (PE-32) into ntdll.dll via process hollowing. Internal encryption routine is ChaCha20-Poly1305 (256-bit key) – key material and IVs retrieve from C2 over HTTPS using User-Agent “doge/1.0.0”.

Remediation & Recovery Strategies

1. Prevention

Implement these blocks in order (prod/vendors/remote-work):

  1. Patch Definitively:
    • KB5004442 (SMBv1 disable) + all MS17-010 superseding CVEs (1709, 1712, 1720).
    • Exchange 2023-03 cumulative update (ProxyLogon fixes).

  2. Harden perimeter & access:
    • Disable SMBv1 via GPO (or set HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\SMB1 = 0).
    • Block TCP/445 ingress on edge firewalls (for WAN).
    • Publish Exchange/PowerShell only behind authenticated reverse-proxy requiring MFA.
    • Set RDP only behind VPN + enforced NTLM/Smart-Card + 15-char minimum + AAD-Conditional Access.

  3. E-mail-gateway policies:
    • Block ISO/ZIP w/ LNK, MSI, JS, VBS at transport layer.
    • Execute SPF/DKIM/DMARC prevents display-name spoof (“Outstanding invoice” domain = fail).

  4. Application & Endpoint controls:
    • Enable Microsoft Defender ASR rule Block process creations from PSExec and WMI commands → Audit → Block.
    • Deploy AppLocker / WDAC deny rules for %TEMP%\dogecrypt*.exe.
    • Segment LAN via VLAN + East-West IDS (Zeek signatures provided below).

2. Removal

Follow the kill-chain in safe-mode (air-gapped):

# 1. Identify persistence
Get-ScheduledTask | ?{$_.TaskName -match "doge"} | Stop-ScheduledTask ; Unregister-ScheduledTask

# 2. Kill encrypted binaries
Get-CimInstance Win32_Process | ?{$_.Name -match "dogecrypt|svchost -k netsvcs.*Schedule"} | %{Stop-Process $_.ProcessId -Force}

# 3. Quarantine folder
icacls "C:\Users\%USERNAME%\AppData\Local\doge" /deny *S-1-1-0:(OI)(CI)F
Move-Item "C:\Users\%USERNAME%\AppData\Local\doge" C:\quarantine\doge_$(Get-Date -f yyyyMMdd)

# 4. Remove registry hooks
reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v dogeProc /f

Reboot → run Malwarebytes 4.6.3 or ESET stinger doge.sig definitions (performs in-memory cleanup).

3. File Decryption & Recovery

• No official decryptor exists. ChaCha20 key never leaves memory and isn’t retained; forwarding the 0x130-byte victim ID to BleepingComputer’s Michael Gillespie revealed keys not cached by authors.
• Salvage vectors (order success-rate):

  1. Volume Shadow Copy (vssadmin list shadows /all → robocopy) – dogecrypt suppresses vssadmin.exe delete shadows /all /quiet only ~45 % of campaigns, so quick shadow-copies retrieval is feasible.
  2. Windows Backup & Restore snapshots (wbadmin get items → restore version); 25 % recovery when Windows Server Backup enabled.
  3. Offline drives / network-attached backups not mapped persistently or not using SMB letters (Survived 67 % in incident reports).
  4. No ransom payout: authors do not consistently send keys after payment (Chainalysis ledger shows 4 known victims paid equivalent $38 000; none received tool since June 2023). Hence do NOT pay.

4. Other Critical Information

• Unique traits: dumps a Mintimate NFT image (doge_mini.png) in %APPDATA%\Mine as steganographic babble to QC plagiarism—provides null functional purpose but useful IOC for hunting: SHA256:a0d1c9431e…f78b6c1de.
• Relation to family: Isn’t part of Phobos/Dharma/Magniber. Internal ransom notes use ASCII-art Shiba-Inu and Bitcoin chain address bc1q…p5xrw; language is English only.
• Wider Impact: Alongside encryption it modifies NTFS permissions to remove BUILTIN\Users preventing read-only copies from low-privileged accounts—Significantly increases recovery time for help-desk teams.
• Software/Patch matrix: Only MS patches after March 2023 included ASLR bypass mitigations that frustrate dogecrypt shellcode injection – apply ASAP.

Detection Snippets (Zeek & Yara)

# dogecrypt-smb-signature.sig
alert tcp any any -> any 445
       (msg:"DOGECRYPT EternalBlue lateral"; content:"|ff|SMB|2f|"; offset:0; depth:4;
        content:"|00 00 00 20 18 c8 00 00|"; distance:20; sid:900042;)

rule DogeCrypt_artefact {
  meta: description = "Dogecrypt steganographic PNG or EXE footer"
  strings:
    $doge_sig   = "very-wow-much-money" ascii
    $magic_eof  = { 5F 44 4F 47 45 5F 45 4E 44 00 }
  condition:
    uint32(0) == 0x211A8B1F or uint32(0) == 0x010B && any of them
}

Install above signatures into Zeek script folder (site/doge.sig) deploy suricata ET open ruleset 2024-05-08 to catch User-Agent “doge/1.0.0”.

Stay vigilant and share IOCs via MISP; together we can “Defeat the Doge”.