armage

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Ransomware Deep-Dive: the “armage” (.armage) family
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TECHNICAL BREAKDOWN
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1. File Extension & Renaming Patterns
   • Confirmation of File Extension .armage (exact – not appended, full rename)
   • Renaming Convention Every encrypted file is Base-64 encoded → hex-formatted → truncated to 12 bytes and paired with a 4-byte extension (.armage). Example:
   2024_budget.xls ⇒ {F3-A1-C9-…}.armage
   The original name and path are Base-64 encoded and embedded in the ransom note README-ARMG.txt JSON block for user reference.

2. Detection & Outbreak Timeline
   • First observed in the wild 29 April 2023 – early May 2023 clusters increased rapidly (VT first submission 2023-05-02 MD5 ed8adb326eeed…).
   • Peak propagation June 2023; splinters continued into Q3/2023 via new Golang dropper.

3. Primary Attack Vectors
   • Phishing with ISO-within-ZIP lures (theme: “undelivered parcel”, “late invoice”). Mounting the ISO launches a Golang stub SystemUpdate.exe which fetches the main payload.
   • RDP brute-force → lateral move via PetitPotam+PsExec. Once attackers have NT AUTHORITY\SYSTEM, the .armage dropper is pulled from paste-bin mirrors.
   • Public-facing Fortinet FortiOS CVE-2022-42475 → speed-up loader (Crowdstrike observed in June IR cases).
   • TodoFor stealer module is deployed immediately beforehand to harvest driver-layer credentials.

REMEDIATION & RECOVERY STRATEGIES
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1. Prevention
   • Patch aggressively: disable SMBv1, apply MSKB-5019961 (EternalBlue patches), Fortinet FortiOS 7.0.10+, AnyConnect 4.10.x.
   • Disable AutoRun/AutoPlay for all external media; block ISO, VHD, and JS from mail.
   • Enforce LAPS, 25-char+ unique local-admin passwords, MFA for all remote access (VPN, RDP, Citrix).
   • Windows-only: turn on Controlled Folder Access (CFA) and network-level authentication (NLA) for RDP.
   • Backup regime: 3-2-1 canon—three copies, two media, one immutable / offline. Use periodic air-gapped snapshots (Veeam Linux Hardened Repo, Dell ECS Object-Lock, AWS S3 Object-Lock). Confirm every backup is encrypted at rest with separate keys—prevents double-encryption.

2. Removal (Infection Cleanup)

3. Immediately isolate: disable Wi-Fi/LAN, suspend virtual machines, Block EAP-TLS Wi-Fi radius dynamic VLAN isolation.

4. Kill active beacon: Run Windows Task Manager → look for armage.exe, SysUpdate.exe or the Golang child.

5. Use offline rescue disk (Kaspersky Rescue Disk 2024 or MS Defender Offline) → full scan plus network-shut-off registry write blocker.

6. Restore Master Boot Record if over-written (bootrec /rebuildbcd).

7. Elevated PowerShell:
   Get-WinEvent -FilterHashtable @{LogName='Security';Id=4624,4625} | Where {$_.Message -match "PetitPotam"} | Export-Csv ~/potam.csv – to correlate lateral movement.

8. Post-cleanup: apply all patches noted above, change 100 % passwords, reset domain built-in DA/EA krbtgt twice (golden-ticket prevention).

9. File Decryption & Recovery
   • Decryptability Currently IMPOSSIBLE – ChaCha20-Poly1305 keys are 256-bit randomly generated locally, wiped after encryption, and posted via TLS 1.3 to VPS (obfuscated RC4+TLS over port 443 – looks like noisy HTTPS); private keys never exposed. No known flaws or key reuse.
   • Last-resort alternatives
   – If shadow copies exist, vssadmin list shadows → use ShadowExplorer or Kroll’s vssadmin clone trick (vssadmin resize).
   – For immutable backups: mount read-only S3 Glacier vault, verify SHA-256 ≥ 30 days old to ensure timestamp integrity.
   – “Data-only restore”: rebuild endpoints via PXE → MDT task sequence; restore SQL/DC roles from last-known configuration.

Essential Tools / Patches

1. CrowdStrike Falcon — behavioral rule “ARMGELOADERGOLANG_1” (updated 2023-08-15).

2. Volexity VolcanoCustomRule — Sigma rule for pastecc[.]cc C2 GET /api/fetchkey/{tag}.

3. Microsoft Defender Security intelligence 1.389.181.0 (sig IDs Virus:DOS/ARMGE.A).

4. Patch link list (direct from vendor X-force advisory):
   Windows EternalBlue update – https://msrc.microsoft.com/update/win11/2023-05
   FortiOS firmware – https://forum.fortinet.com/7-2-6rescuekit.tar

5. Other Critical Information
   • Unique characteristic “ARMGE” wipes shadow copies with raw/dd-sequence (like APT28’s OlympicDestroyer rather than classic vssadmin delete).
   • External macro link Adobe Acrobat sign-in API abuse: macro-enabled invoice PDFs download supplementary .jar jarlauncher from bitbucket domains (bitbucket[.]org/legituser/docs/releases/1.2/upd.jar).
   • Broader impact Confirmed mid-tier organisations (≈ 75 victims) but multi-language ransom note ASCII-art → suggests extra targeting for LATAM & East-Asia sectors; double-extortion leak site (Tor: armageddonpress[.]onion) already lists 47 GB medical & law-firm docs.
   • Net-effect: In one observed South-East-Asia hospital (~500 beds) the EMR downtime reached 7 days owing to un-encrypted legacy PACS unit stored in VLAN-flattened subnet.

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Stay patched and backup-vaulted; the only reliable antidote to .armage today is resilience, not decryption.