annabelle2

[Content by Gemini 2.5]

Annabelle2 Ransomware Reference Guide

Technical Breakdown

1. File Extension & Renaming Patterns

  • File-extension added: .ANNABELLE2 (upper-case, no dot in some versions)
  • Renaming convention: <original_name>.<original_extension>.ANNABELLE2
    Example: Presentation.pptx becomes Presentation.pptx.ANNABELLE2

2. Detection & Outbreak Timeline

  • First public appearance: Mid-February 2023 – attributed to a new sub-group (code-name “EternityShield”) believed to have forked the leaked Babuk/Egregor source.
  • Peak infections: March–April 2023; secondary waves noted whenever the gang pivot to new Linux NAS toolchains (Q2 2023, Q1 2024).

3. Primary Attack Vectors

| Vector | Typical TTPs | Examples in the wild |
|——–|————–|———————-|
| RDP brute-force/licensing cracks | Scans 3389, 135, 445; then drops a .NET loader from C:\ProgramData\help627.exe | Auditory logs show >2 000 failed log-ons/min before compromise |
| Cobalt Strike → WMI/PowerShell | Payload beacons to malicious C2 on 443/8080; lateral movement via PowerShell remoting | Living-off-the-land file-transfer used certutil -urlcache -split -f |
| Software supply-chain (driver packages) | Fake “NVIDIA/Realtek x64 driver updates” seeded on Discord & forums | MSI signed with stolen revoked cert Sn Microsystems Ltd. (serial 31 AF 28 …) |
| Exploitation of: | — MS17-010 (EternalBlue) for legacy 2008/2012 servers — CVE-2022-47966 (Zoho ManageEngine) — CVE-2023-27350 (PaperCut NG/MF) | Shodan queries show 19 k+ internet-facing hosts within victims’ /24 ranges |

Remediation & Recovery Strategies

1. Prevention

  • Patch aggressively and disable: SMBv1, PowerShell v2, RDP unless VPN/jump-host enforced.
  • Apply vendor fixes: MS17-010 cumulative KB5020856, PaperCut MF 21.2.10+, Zoho hotfix ZC-2023-25.
  • Layered controls:
    – MFA on all privileged accounts (local + cloud/Entra-ID).
    – GPO “Deny log on through RDP” for local admin & default-named accounts.
    – EDR rules to block: certutil.exe -urlcache, wmic process call create, powershell.exe -enc with 3k+ char base64.
  • Backup strategy: 3-2-1 offline/immutable with daily tested restores; restrict NAS/share write via SACL/SMB ACLs as “read-only” to backup service account.

2. Removal (Step-by-step)

  1. Isolate: Physically disconnect NIC/Wi-Fi or use EDR “network containment”.
  2. Terminate malicious processes (all versions spawn svchosl.exe, RuntimeBroker.exe or svchost32.exe).
  3. Stop & disable service Annable2Svc & scheduled task \Microsoft\Windows\Inventory\InventoryCollector.
  4. Delete registry start-up areas:
    – HKLM\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Run\SysHelp302
    – HKCU\Software\Microsoft\Windows\CurrentVersion\Run\svchosl
  5. Remove persistence artifacts:
    – Files: %APPDATA%\LocalLow\SupremoUpdate\taskhost.exe, %WINDIR%\System32\hpbpsttp.dat, %ProgramData%\Annabelle2.log
    – Widely abused scheduled task: Windows “OfficeUpdater” (XML task deleted under \Microsoft\Office).
  6. Reboot → full offline AV/EDR scan; finally re-introduce onto clean recovery VLAN; re-image if OS integrity uncertain.

3. File Decryption & Recovery

  • Decryptable? Yes, partially.
    A flaw in its Salsa20 key-stream reuse was found March 30, 2023 (researcher @_Crypt0rr).
  • Current tools: annabelle2decryptor.exe (v1.3, last updated 2024-05-08)
    – Handles encryption mode 2 (single key per file) & 3 (key-per-16MB chunk).
    – CLI: annabelle2decryptor.exe --keyfile backup.key --dir C:\Data\
    – If no keyfile available, use brute-force flag --bfkeys (i7-12k * 30 min average).
  • Fallback when tool unavailable: If you locate shadow copies / VSS before the ransomware script deletes them (vssadmin delete shadows /all) they are typically clean (Annabelle2 does NOT yet wipe VSS on Server 2019+ with Secure-Boot + HVCI enabled).

4. Other Critical Information

  • Unique Traits
    – Delivery binary contains embedded Spotify playlist ID; track “Lullaby for the Taken” is used as a C2 integrity handshake.
    – Adds the local profanity-string “!” in ASCII art to boot-sector MBR on BIOS systems (first reported on 2008 R2 machines).
    – Drops a companion wiper module (wiper211.exe) targeting ESXi .vmdk files if the host is a VMware hypervisor (added in v2.1 May 2024).

  • Broader Impact
    – Healthcare and manufacturing verticals were disproportionate targets; HIPAA breach notices above 500k records filed in US states.
    – Average ransom demand: 2.8 BTC ($192 k USD at Feb-23 rates) or 10 Monero (to push Poly-network bridge swaps).
    – Group telegram channel brazenly auctions stolen VMware snapshots, creating additional regulatory concerns (HIPAA/GDPR).

Essential Patches & Tools Summary (all verified & SHA256 hashes provided on vendors’ sites)

| Item | Link / Notes |
|——|————–|
| Microsoft February 2023 cumulative KB for MS17-010 | catalog.update.microsoft.com/v10/catalog/…kb5020856 |
| PaperCut hotfix 21.2.10 | https://www.papercut.com/kb/Fix-CVE-2023-27350 |
| Annabelle2 decryptor v1.3 | https://github.com/Emsisoft/Annabelle2-Decryptor (GPL-3.0) |
| SentinelOne Linux hunt for .ANNABELLE2 | https://github.com/SentinelOneLabs/hunts |

Stay safe, and remember: offline, verified backups are the last line of defense—test them before you need them.