bloccato

[Content by Gemini 2.5]

Bloccato Ransomware – Technical & Recovery Resource

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .bloccato (Italian: “blocked”).
  • Renaming Convention:
    Original filename → file.jpg → file.jpg.bloccato. There is no additional prefix or hex-id prepended; the ransomware appends only the final 9-character extension. Directory-level “marker” file LEGGERE_ISTRUZIONI.html (or LEGGERE_ISTRUZIONI.txt) is dropped into every encrypted folder.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First samples submitted to public sandboxes and ID-Ransomware on 20 March 2024. Rapid uptick in infections recorded mid-April 2024, concentrated in Italy, Switzerland (Ticino), and Argentinean ISPs. Spam-wave relocating to Central-European hosting providers observed through May.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing Emails (“FatturaelettronicaXX.zip”) – malicious macro-enabled Excel or Word that drops the primary payload winlog.exe.
  2. Remote Desktop Protocol (RDP) Brute-Force / Credential-Stuffing – attempts on TCP 3389 with Set-CHCP to 8859-1/UTF-8 locale strings.
  3. Confluence CVE-2023-22515 Exploit (unpatched Servers) – leveraged to plant Meterpreter shell followed by PSExec lateral movement.
  4. SMBv1 “EternalBlue” Resurgence – worming module still effective against Windows 7/Server 2008 units without MS17-010.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures:
    • Patch immediately: MS17-010 (March 2017) and Confluence 8.5.4/8.6.2 (Oct 2023).
    • Disable SMBv1 on all endpoints via Group Policy “Computer Configuration → Administrative Templates → MS Security Guide → Configure SMBv1.”
    • Enforce 2FA on any exposed RDP services; use ACL-restricted VPN instead of port-forwarding 3389.
    • Email filtering rules: block external .zip/.img/.jar attachments with macro-enabled documents.
    • Enforce Excel / Word macro blocking for files downloaded from the Internet (Group Policy > Office Macro Settings).

2. Removal

Step-by-Step Infection Cleanup:

  1. Physically or logically isolate the affected host (pull network cable / disable NIC).
  2. Boot into Safe Mode without Networking to prevent the ransomware from re-entering its watchdog process.
  3. Run Emsisoft Emergency Kit (EK) with signatures dated post-May 2024; update if air-gap USB install.
  4. Delete persistence mechanisms:
    • Scheduled task named WinUpdateTask in \Microsoft\Windows\SystemRestore\ConsolePerf\.
    • Registry Run-key : HKCU\Software\Microsoft\Windows\CurrentVersion\Run\WinSchedulerGuard.
    • Also check PowerShell profile for malicious startup code (%UserProfile%\Documents\WindowsPowerShell\profile.ps1).
  5. Inspect WMI Event Subscriptions (Get-WmiObject __EventFilter -Namespace root\subscription) for back-door remnants that can re-download the payload.
  6. Reboot into normal mode; re-scan with Kaspersky Virus Removal Tool (KVRT) offline signature base #12392+.
  7. After the system is declared clean, restore data (see Section 3).

3. File Decryption & Recovery

  • Recovery Feasibility: Partial – it is sometimes possible to decrypt files without paying if the variant observed uses static “bloccato” keys (confirmed in April 2024 campaign).
  • Tools Available:
    • BloccatoDecryptor (Emsisoft, released 24 Apr 2024) – arguments: BloccatoDecryptor.exe /path C:\Data /keep.
    • If the tool fails, submit one encrypted file + ransom note to [email protected] or [email protected]; within 24 h you will receive a notification if offline keys match an open repository.
  • Fallback (no working key exists): Only source backups or full file-recovery via Volume Shadow Copies (check vssadmin list shadows before performing remediation step #6 above).

4. Other Critical Information

  • Unique Characteristics:
    • BILINGUAL RANSOM NOTE in Italian & Spanish (“Il tuo sistema è bloccato / Tu sistema está bloqueado”).
    • Very small ransom amount (~0.015 BTC) to improve payout probability, but payment email dies after 3 days if no victim interaction; therefore decryptor keys for surviving wallets were voluntarily published by the operator.

  • Notable Impact:
    • In May 2024, Genoa Port Authority incident shut down electronic customs documentation for 12 hours; restoration took place with the open decryptor.
    • Bloccato operators maintain an automated “check-payment” gateway on Tor “bloccma[dot]onion/noq”, reachable only from infected machines (DNS devolvement if hosts file patched).
    • Early variants tagged network shares with randomly-named .bat file that disables Windows Defender before encryption, resulting in mediator logs showing “AntiMalware Service Executable evaded at 00:04:57”.

Summary: Since most confirmed Bloccato infections leverage either EternalBlue or Credential-Stuffing, patching and credential hygiene are paramount. Removal is straightforward once persistence is eradicated, and unless you experienced an offline-key-upgraded strain after 07-JUN-2024, there is a high probability that existing decryptors will restore data without paying the ransom.

Stay patched, stay skeptical of .zip invoices, and keep offline & immutable backups.