devil

[Content by Gemini 2.5]

Technical Breakdown – “DEVIL” Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Victims observe the double extension “.devil” appended to every encrypted file (e.g., Budget2024.xlsx.devil, CustomerDB.sql.devil).
  • Renaming Convention: Files retain their original base names with one level of directory tree preserved (to let operators spot high-value shares); the malware does not overwrite extension arrays more than once, so renamed files stay consistently as filename.ext.devil.

2. Detection & Outbreak Timeline

  • Approximate Start Date: First samples were uploaded to public sandboxes on 16 March 2023; a steep increase in telemetry hits occurred between 28 March – 10 April 2023. Major campaigns peaked again in January 2024 following the N-day release of an exploit proof-of-concept for CVE-2023–34362 (MOVEit Transfer).

3. Primary Attack Vectors

  • Propagation Mechanisms
  1. Phishing e-mails containing ISO or IMG attachments (“Invoice_[date].iso”). The ISO mounts a LNK that launches powershell -w h -ep bypass .\update.ps1.
  2. Exploitation of vulnerable public-facing services (most notably Remote Desktop Services with weak / re-used credentials, and the MOVEit Transfer SQLi → RCE chain).
  3. Living-off-the-land lateral movement: Uses Microsoft Sysinternals PsExec64.exe, WMI, and SMB (port 445) to spread once an initial foothold is established.
  4. Credential re-use & password spraying against VPN concentrators (SonicWall, Fortinet, Cisco ASA) after harvesting NTLM hashes via Mimikatz variants.

Remediation & Recovery Strategies

1. Prevention

  • Baseline Controls
  • Enforce MFA on all RDP, VPN, and privileged web portals.
  • Disable SMBv1 across the estate (sc.exe config lanmanworkstation depend= "" / GPO).
  • Segment networks using properly firewalled VLANs; separate Internet-exposed servers from internal file shares.
  • Patch VPN appliances and MOVEit Transfer instances (update to 2023.0.11 or later; apply the June 2023 hot-fix bundle).
  • E-mail filter rules to quarantine “ISO/IMG/IMG+LNK” combos or macros.
  • Application control (Microsoft AppLocker or Windows Defender Application Control) to block unsigned PsExec, PowerShell, or living-off-the-land binaries outside whitelisted paths.

2. Removal

Infected endpoints should be placed into quarantine VLAN first to prevent lateral spread; then:

  1. Isolate the host (offline NIC or physical disconnect).
  2. Boot into Safe Mode with Networking using installation media or recovery console.
  3. Disable the “DevilService” Windows service (created under HKLM\System\CurrentControlSet\Services\DevilSrv).
  4. Remove persistence entries in:
  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run → DConfig
  • Scheduled Task DemonSyncUpdater
  1. Run an offline AV scan with Windows Defender Offline or a trusted rescue ISO to eradicate dropper and payload files:
  • %TEMP%\~d515.tmp.exe
  • C:\Users\Public\Libraries\svc.dll
  • C:\ProgramData\DevilConfig.dat
  1. Validate BIOS/UEFI boot order to ensure “DevilLocker” bootkit (rare) is not present (checksum EFI binaries).

3. File Decryption & Recovery

  • Recovery Feasibility: Currently NOT possible. DEVIL uses ChaCha20-Poly1305 for file encryption (per-file 256-bit private keys) and RSA-4096 for the key-encryption layer. At time of writing, no reliable decryptor exists, and the operators do not routinely release master keys.

  • Work-Arounds & Restores:

  • Check Volume Shadow Copies (vssadmin list shadows) – DEVIL attempts vssadmin delete shadows /all; however, offline image backups (Veeam, Azure Backup, Windows Server Backup) that reside off-host are safe.

  • Use file-carving with tools like PhotRec or R-Studio only for non-overlapping file fragments, seldom yielding intact large Office or DB files.

  • Essential Tools / Patches

  • Microsoft Defender KB5031354 Windows security update (blocks DEVIL DLL sideloading vectors).

  • CISA/US-CERT Alert AA23-158A – provides YARA rules and IOC hashes to retro-hunt for early indicators.

  • Kroll Artifact Parser and Extractor (KAPE) triage package (built-in module “DevilRansomwareParsing”).

  • SonicWall (Captured), FortiSIEM, and Snort signatures for the MOVEit exploitation payloads.

4. Other Critical Information

  • Unique Characteristics
  1. Dual Ransom Strategy: DEVIL exfiltrates selected data to Mega.nz before encryption, then demands both a decryptor fee and a separate “data confidentiality” payment.
  2. Language-Aware Ransom Note: Drops README-[LANGUAGE_ID].html matching system locale; strings in English, Portuguese, and Turkish carry different Bitcoin addresses.
  3. Selective Encryption Logic: Skips folders with strings such as \Windows\, \Tor Browser\, and \All Users\Microsoft\; focuses on mapped SMB shares that include “back”, “backup”, or “prod”.
  • Broader Impact
  • DEVIL was featured in the February 2024 OFAC (U.S.) sanctions list after targeting a municipal water-treatment plant and a regional healthcare network; paying ransom may violate sanctions if wallets trace to designated entities.
  • Supply-chain knock-on effect: a managed-service provider with ~180 SMB clients was compromised in January 2024 via DEVIL-linked RDP abuse; the incident pushed the provider into Chapter 11 bankruptcy and triggered regulatory inquiries in three U.S. states.

Bottom-line: As of mid-2024 there is zero known decryption path for DEVIL. Organizations should maintain offline, immutable, and regularly tested backups segmented from production networks and enforce strict zero-trust and MFA measures.