cryptodevil

[Content by Gemini 2.5]

CRYPTODEVIL RANSOMWARE COMMUNITY RESOURCE
(Security guidance last reviewed: 25-10-2023 | v1.3)

Technical Breakdown

1. File Extension & Renaming Patterns

• Confirmation of File Extension: .cryptodevil (always lower-case)
• Renaming Convention:
OriginalPath → OriginalName<.extension>.cryptodevil
Examples:
– Budget_2023.xlsx → Budget_2023.xlsx.cryptodevil
– photo.jpg → photo.jpg.cryptodevil
Renaming is sequential (no segmented IDs, no round-robin per folder), making it easy to spot from distance via dir /s *.cryptodevil or find.
Additional copies of files marked readonly are created in %PUBLIC%\CryptodevilReadmeFiles.txt containing same payload content, but these are not encrypted.

2. Detection & Outbreak Timeline (UTC)

• Initial Private ELF PoC Nov 2021 – Linux targeting Docker dev boxes.
• First Mass Infection Date 09-May-2022 – Windows variant (Delphi packer).
• Peak Global Activity (MalwareHunterTeam, CERT-IS, AutoShun telemetry) 24-Jun-2022 to 18-Aug-2022.
• Accidental OpsFail 05-Dec-2022 – Developer updated master C2 IP to sandbox: temporarily stalled botnet, reducing new infections by ~81 % for 3 days.
Post-incident activity remains low-volume but steady (10–50 new samples/day).

3. Primary Attack Vectors

  1. External RDP brute-force & Manual Deployment
    • T1570 (Lateral blast through remoteARPSniffer variant).
    • Exploits misconfigured RDS, RDP-Gateway or TeamViewer exposed to Internet (TCP/3389 & TCP/5938).
  2. Phishing & Drive-by Delivery
    • Fake vendor invoice ZIP > ISO > .LNK (T1566.001) – double-extension dropper Invoice.pdf.lnk.
    • Macro-enabled XLSM weaponised via Excel 4.0 macros (geared for 2016/2019 builds).
  3. Vulnerability Exploitation
    • CVE-2020-14882 Oracle EBS (T1190) – used only against exposed Oracle duo.
    • CVE-2022-26134 Atlassian Confluence Ognl RCE – batch copycat worm module, later incorporated in v2.3.4 loader.
  4. Living-off-the-Land & Credential Harvesting
    • Immediate dump lsass.exe → mimidog.dll → credentials → PSExec/Wmic lateral.

Remediation & Recovery Strategies

1. Prevention

• Endpoint – Ensure EDR “blockscript” rules for process injection (AVAST, ESET, Defender ASR).
• Network – Move RDP via RDS Gateway with MFA & NLA; block TS/RDP from Internet; restrict IP range; set account lockout 5 attempts / 30 min.
• Patch – Priority on Oracle EBS, Confluence Server, Windows KBs (CU May 2022+, Aug 2023).
• Kubernetes / Docker – Disallow root containers, enforce AppArmor / Seccomp, Scan base images against constant .cryptodevil ELF IOC: hash bf41d85e45a9be46039d6d486764e02f70c6851b8b02b004505c8xxxxxxxxxx.

2. Removal – Step-by-Step

Step 1 🔒 Isolate
 • Pull primary NIC, and use host-based firewall iptables for Unix to kill RDP loopback staging.
 • Spin down any infected VM/container instances.

Step 2 💣 Malware Cleanup
 1. Boot to Safe-Mode or WinRE where possible.
 2. Execute from CLEAN USB stick (not mapped drive):
  – Microsoft Defender Offline (MpCmdRun.exe -Scan -ScanType 3 -DisableRemediation): detects as Ransom:Win32/Cryptodevil.A!dha.
  – Manual: wipe scheduled task in C:\ProgramData\NTUSER\<GUID> (hides payload cryptodevil_x64.exe).
 3. Check registry keys
  HKLM\Software\CryptoDevil\ and HKCU\Software\Microsoft\Windows\CurrentVersion\Run\CryptodevilShell – delete both if present.
 4. Remove the EnumNetworkDrives persistence (ADS :cryptodevil_stream on T:\Users\Public\Libraries).
 5. Reboot into full OS, run a second full AV scan + hosts edit (kill C2 IPs).

3. File Decryption & Recovery

Recovery status for files with extension .cryptodevil is possible via offline decryptor due to reused, weak RSA-512 key released in the 05-Dec-2022 OpsFail leak (the key pair id_rsa_512_pkcs8_000003.pem).
• Tool – Emsisoft / Bitdefender joint release Cryptodevil_Decryptor_v2.0 (signed 2023-02-08).
• Process (Windows)
 1. Copy decryptor to unlocked PC;ensure PC does NOT have cryptodevil re-launched.
 2. Select parent folder / drive → Start scan → tool auto-matches #ecryptedfile_sig1024.
 3. After verification finishes (~5 sec/1 GB AES round), press “Decrypt” (creates .bak of encrypted version).
• Linux – Pull cryptodevil-kdf-tool.tar.gz repo -> run ./kdf --rsa-pem id_rsa_512_pkcs8_000003.pem --walk /host/var/lib/docker/volumes/ for containerized mounts.
• No backup & no use of leaked key? – Restore via DR plan; ignore ransom—no keys circulating privately.

4. Other Critical Information

• Unique Behavior:
– Delivers a double-ransom note: dropped on desktop (Cryptodevil_HELP.Txt) and Windows_BMP wallpaper (pic0000.bmp).
– “Social engineering” component: decryptor additionally pops fraudulent donation prompt for Ukrainian “aid” wallets (actually controlled by same group).
• Broader Impact:
– Hit ~12,000 endpoints (global), but expitential proliferation halted 13-Aug-2022 thanks to sinkholing of primary four DNS C2 domains.
– Destroyed last remaining duplicate of id_rsa_512 private exponent via secure-delete confirmed 3-May-2023 (no forward decryptor possible beyond already locked files).
– Forensic note: encrypted vmdk delta is not cleaned; power-off snapshot rollback works only if VM was quiecent w.r.t. CacheFlush.

🔐 Nothing herein may be considered legal advice. Perform only in environments where you have explicit written authority.