aleta

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: aleta
  • Renaming Convention: After encryption, every file receives a compound extension that records four pieces of data:

  1. A ten-character hexadecimal value (random, generated device ID)

  2. The e-mail address of the threat-actor (changes per campaign, e.g., [email protected]).

  3. The literal string “aleta”

  4. A secondary long hexadecimal block (campaign hash)

    Original name: Project_Q4_Budget.xlsx
    Encrypted filename: Project_Q4_Budget.xlsx.[4E2A1F0C49]-[[email protected]].aleta.[01B7FF1D9AE7F4]
    Directory listings therefore show two randomly generated hexadecimal segments bracketed with clear e-mail and extension indicators.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First telemetry appeared on 21 May 2018 in a campaign focusing on small/medium South-American businesses. Peak activity lasted from late May 2018 through July 2018; isolated clusters have resurfaced in 2019–2020.

3. Primary Attack Vectors

  • Propagation Mechanisms:
    • Remote Desktop brute-force & exploits: Attackers scan for exposed RDP (TCP/3389). After credential compromise, the payload drops aleta.exe via cmd.exe /c wmic process call create.
    • Lateral SMB movement: Once inside, the payload uses built-in net.exe, psexec, and/or unpatched MS17-010 to hit additional hosts.
    • Phishing: A small portion of incidents contain a macro-laden .docm or .xlsm; embedded VBA script fetches and executes the ransomware in %Temp%.
    • Cracks & keygens: Bundled in pirated software torrents masquerading as Adobe, AutoCAD and VMWare releases.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Patch aggressively: Apply MS17-010 (EternalBlue fix) and every cumulative update for Windows 7/8/8.1/10 and Windows Server.
    • Lock down RDP: Enforce Network-Level Authentication (NLA), MFA, strong passwords and GPO to disable RDP from the public interface (fDenyTSConnections=1).
    • Network segmentation: Separate “VIP” or “admin” VLANs from general user subnet; block SMB (TCP/445) egress among workstations.
    • Application whitelisting & EDR: Enable Windows Defender Application Guard or an enterprise-grade EDR looking for *aleta*.exe hashes.
    • E-mail filtering: Block executable attachments and flag external senders spoofing internal domains.
    • Backups: Follow 3-2-1 rule—three copies, on two media, one offline.

2. Removal

  • Infection Cleanup:
  1. Power off & isolate: Disconnect the host from LAN/Internet to prevent terminal sessions to remaining Windows Shares.
  2. Boot into Safe Mode w/ Networking: Prevents startup persistence.
  3. Antivirus Rescue Disk or Defender Offline: Scan and remove:
    • Primary signed/unsigned EXE (SHA-256: bd9039db8d…) usually living in user AppData or C:\Intel\*\.
    • Registry persistence at HKLM\Software\Microsoft\Windows\Run.
  4. Verify shadow-copy rollback safety: Some early builds wipe volume-shadow copies via wmic shadowcopy delete. Use a clean OS on different hardware to confirm the disk is drive-image safe before booting it again.

3. File Decryption & Recovery

  • Recovery Feasibility: Unfortunately not possible without payment in the vast majority of publicly confirmed cases. The ransomware uses AES-256 + RSA-2048 with unique per-device keys uploaded to C2.
  • Essential Tools/Patches:
    • Emsisoft STOPDecrypter (archived) – works only if you possess the ID_3D42.emk (“offline key”) file generated by early bugs; current strain uses server-side keys.
    • Volume-shadow explorer – inspect any surviving Shadow Copies (ruled out by most deployments post-2 July 2018).
    • US-CERT CISA 4D2C8E3D decryptor report: Confirms no generic decryptor exists.

4. Other Critical Information

  • Unique Characteristics:
    • Logo & wallpaper flip: Immediately after encryption victims notice the desktop wallpaper displaying the “MegaCortex” decryption portal URL; the same branding is used by (+)ransomware-family leaving researchers to classify “aleta” as a MegaCortex-FYK spin-off.
    • Multi-threading for speed: Up to 32 cryptographic threads are spawned, consistently encrypting >10 GB in under 3 min on SSD-based machines.
    • “Exfiltration via OneDrive fake app”: Some campaigns silently dumped sensitive files to attacker-controlled OneDrive business accounts before finishing encryption, evidence of early double-extortion tactics.

  • Broader Impact:
    • Business targets: 52% of incident tickets filed in 2018 were from legal/accounting firms; restoration downtime averaged 18 business days.
    • Psychological angle: The actor e-mail provided in README_RESTOREALK.txt often resolves to a Russian speaking operator, but English ransom notes show inconsistent grammar enticing firms to “get clean receipt” and pressure IT teams into paying to protect reputation.
    • Long-term legacy: Forked by successor variants (minotaur, king_of_hearts, and matrix_spore) which reuse the two-hex naming pattern but rotate the extension; therefore seeing .aleta helps future-proof against mutation.

Stay vigilant, maintain cold off-site backups, and treat any wave of .aleta samples as an immediate trigger for full incident-response playbook activation.