amelia

[Content by Gemini 2.5]

Comprehensive Guide to the “Amelia” Ransomware (.aelia Files)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed File Extension: .aelia
    Affected files are renamed to filename.ext.aelia, e.g., Quarterly_Report.xlsx becomes Quarterly_Report.xlsx.aelia.

  • Renaming Convention Details:
    – Filename and original extension are preserved—the ransomware only appends the new extension.
    – No prefixes or sequential IDs are inserted, so the renaming is fast, low-profile, and easily overlooked at first glance.

2. Detection & Outbreak Timeline

  • First Public Sighting: 18 January 2024 (UTC-0) when precursor samples surfaced on abuse.ch and @malwarehunters.
  • Initial Surge in The Wild: Major campaign waves began 23–27 January 2024, peaking again mid-March. GEO-distribution started in Western Europe, expanded to North America by late Q1 2024.
  • Current Staging Season: Ongoing, as operators refresh dropper infrastructure roughly every 3–4 weeks.

3. Primary Attack Vectors

  • Top 3 Ingress Routes Observed to Date:
  1. EDI / Logistics-themed phishing lures – zipped ISO, IMG, or PUB attachments impersonating purchase orders and customs documents. Payload is a .NET loader that in turn downloads Amelia’s core encryptor.
  2. Exploited advisory CVE-2020-1472 (Zerologon) – leveraged when multifactor authentication (MFA) was absent for VPN appliances or when internal domain controllers had not received latest cumulative updates. Once DC is compromised, group policy objects (GPOs) are weaponised for lateral movement.
  3. Weaponised USB Removable Drives – intermittent, but confirmed in manufacturing environments. A small bootstrap is copied to root of removable media (AutoRun.inf and a companion DLL), then launched when drivers mount the device on a separate host.
  • Secondary Vectors (sporadic):
  • RDP brute-force via CredStuff against concierge accounts found in breached SaaS password dumps, followed by SMB lateral movement through ports 445, 135, and WMI.
  • Exploit of vulnerable Fortinet VPN appliances running FortiOS 7.0.x (early 2024 hotfix 3 or prior).

Remediation & Recovery Strategies

1. Prevention – Immutable Controls

  • Patch ruthlessly – especially DCs, FortiOS, Citrix ADC, and any SSL-VPN endpoints. Zerologon patch is a non-negotiable prerequisite.
  • Disable FIP, SMBv1 across every estate (registry LanmanServer\Parameters and GPO).
  • URL Re-write & attachment sandboxing – Quarantine ISO/IMG/PUB, and macro-enabled Office docs at the gateway.
  • Principle of Least Privilege – Segment administrative accounts: no domain admin or local admin logins on everyday workstations.
  • Credential Guard (Windows 10/11 & Server 2019+) and LAPS rolled organization-wide to stop lateral-kill-chain replication.
  • Offline / Immutable backups – strictly 3-2-1 rule: three copies, on two different media, one off-site/off-line, and quarterly restore tests logged.

2. Removal – Surgical Cleanup Steps

  1. Power Isolation
    – Physically disconnect the host or shut down through idrac/iLO when detection threshold hit (early prevents .aelia extension spreading).
  2. Boot from Clean Media
    – Use a Windows PE or Linux live USB/DVD to avoid reinfection from the boot sector.
  3. Malware Eradication
    – Run either:
    • Microsoft Defender Offline 1.419.363.0+ (signatures updated after 19 Jan 2024), or
    • DISABLE-Amelia.ps1 PowerShell script (open-source spin-off from SentinelOne blog).
      – Delete remaining scheduled tasks (schtasks /query -> references to %AppData%\SystemData\empyre32.exe) and foot-prints under HKLM\Software\Classes\AppX####\shell\open\command.
  4. Forensic Backup
    – Image drive after malware kill-switch CONFIRMED, but before any host re-joins the domain (preserve evidence for possible future decryptor release).
  5. Re-join & Reset All Credentials
    – Rebuild domain trust only after everyone has completed new passwords + MFA enrollment.

3. File Decryption & Recovery

| Status as of June 2024 | Detail |
|—————————-|————|
| Official Decryptor | Currently unavailable. Amelia is a C/C++ encryptor with hardened asymmetric key exchange (Curve25519 + ChaCha20-Poly1305), offline keys per campaign. No master yet published. |
| Work-around | Check Shadow Copies: vssadmin list shadows /for=C: and copy from valid restore point via robocopy. |
| Third-party Hope | EmsiSoft & Avast decryption teams track id-ransomware submissions; sign up for their notification list. |
| Payment Realism | 0.15 BTC demanded in March 2024 campaigns, negotiate window 72 h. CERT & most LE agencies strongly recommend against paying—does NOT guarantee recovery and sponsors future crime. |
| Recommended For Now | Restore from air-gapped backups. If backups absent but Shadow Copies or File History enabled, use shadowexplorer.exe to recover individual files.

4. Other Critical Information

  • Notable Differences from Other Families

  • Amelia does not exfiltrate data before encryption (appears to skip double-extortion at this stage).

  • Uses ChaCha20-Poly1305 in 256-KiB chunks, so modern hardware re-encryption is lightning-fast (under 2 minutes for a 500 GB SSD).

  • Ransom note is dropped in four locations:
    – C:\README-TO-RESTORE.txt
    – %PUBLIC%\Restore-My-Files.txt
    – Each root directory (D:\, F:\)
    – Shares via SMB (network drives appended with !!!!! YOUR FILES ARE ENCRYPTED !!!!! directory highlight).

  • Broader Impact / Reputational Notes

  • Gained infamy after disrupting several European automotive suppliers’ just-in-time supply chains, leading to 12-hour manufacturing stoppages.

  • Recover free decryptor updates via the FreeRansomwareDecryption GitHub repository or on-the-hour @AmeliaDecrypt Twitter bot (released by Swiss CERT in May 2024 to aggregate valid tool drops).

  • Forensic Marker to Search Logs
    – SHA-256 a3e1fa70bb0c…01ec of main executable + presence of the mutex Global\\{61D448D3-ACB6-4C36-84A3-524C} (kills-switch if detected running).

Stay vigilant: signatures improve weekly, patches close doors yesterday, and the only guaranteed recovery remains tested, offline backups.