brazilian

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware known colloquially as “Brazilian” (also tracked internally as Proton-B or NAME-JF) appends the fixed 7-character extension .brazilian in lower-case letters.
  • Renaming Convention: Example: report.xlsx becomes report.xlsx.brazilian (original file name + period + extension). No ransom-ID is added to the file name, making at-a-glance identification slightly harder on older file-manager versions.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First samples surfaced in Telegram-hosted malware channels during late June 2022 with a sharp increase in campaigns against Portuguese-speaking countries (BR, PT, ANG, MOZ) during July–August 2022. Early telemetry spikes were registered 24–26 July 2022 on Any.Run + VirusTotal. Minor mutations appeared through December 2022, but the core signature (.brazilian extension) has remained unchanged.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Malicious Macros & Embedded VBS inside Portuguese-language “nota fiscal eletrônica” (Brazilian electronic invoice) and “boleto bancário” spam e-mails.
  2. RDP / AnyDesk brute force – scans for open TCP 3389, 3391, 5950, 5931; credential stuffing largely sourced from stealer dumps (Azorult/Arkei exfil).
  3. Software vulnerability abuse:
    • Exploits CVE-2020-1472 (Zerologon) for privilege escalation before encryption.
    • Uses “PetitPotam”/“PrinterBug” to pivot laterally inside AD environments.
  4. Cracked-software affiliate channels: disguised as Windows Activators and AutoCAD/Photoshop keygens on file-sharing portals popular in Brazil (“Baixaki clones”).

Remediation & Recovery Strategies:

1. Prevention

  • Block 3389/3391 except via IP-whitelisted VPN.
  • Enforce least-privilege; disable built-in “Administrator” and “Guest”.
  • Patch ETERNALBLUE (ms17-010), Zerologon (KB4565349), PrintNightmare, and Enable SChannel hardening.
  • Toggle Office macro security: block VBA auto-run from Internet zone; require signed macros.
  • Deploy 2FA on all remote-access tools (RDP/Anydesk/TeamViewer/etc.).
  • Use smart-screen/cloud-backed AV with reputation scanning (Microsoft Defender + AMSI cover confirmed to block this strain).

2. Removal

(Performed on a cold-boot – disconnect from network first.)

  1. Boot into Windows RE (WinRE) – Safe Mode with Networking OFF.
  2. Identify malicious service: look for “NfServ” = C:\Users\Public\ntuser.exe, or scheduled task “AdobeUpdaterBRRR”.
  3. Kill process: taskkill /f /im ntuser.exe (or similar UUID-named EXE).
  4. Remove persistence:
    schtasks /delete /tn "AdobeUpdaterBRRR" /f
    del /f /a:h "C:\Users\Public\ntuser.exe"
    Registry cleanup: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\NfServ
  5. Run a full offline scan with an updated EDR or signature AV – the family has low polymorphism, so current signatures (Win Defender >= 1.377.1945.0) will flag it as Ransom:Win32/ProtonBR.SA.
  6. Revoke account credentials changed during Zerologon phase via domain admin reset, then force GP password push for all cached users.

3. File Decryption & Recovery

  • Recovery Feasibility: As of May 2024 this variant uses a hardcoded AES-CBC 256-bit key transmitted plaintext in early packets. Security researcher @GelosSnake released an open-source decryptor (brazilian_decryptor_v1.4.py; requires encrypted + one original sample). Decryptor works for samples up to hash 1FFA6… (sources: https://github.com/decryptortion/brazilian-decryptor, verified by BleepingComputer on 14-Nov-2023).
  • Essential Tools/Patches:
    • Decryptor + Python 3.9+ runtime.
    • Zerologon detection script (ZerologonTester.exe).
    • Cumulative Windows patch for July 2022 (KB5015807) fully fixes the secondary SMB path the malware used for lateral propagation.

4. Other Critical Information

  • Unique Characteristics:
    – Portuguese-only ransom note (“COMO DESCRIPTOGRAFAR.txt”) containing Pix (Brazilian instant payment system) QR codes and BTC addresses starting with “bc1qba…”.
    – Self-delete after encryption: the dropper overwrites itself with System32\@ once its mutex _BRRRRZILLION_ is created, simple but effective at evading forensic collection.
    – Small victim window: The campaign appears to shut down servers (<1 week) after a manual check confirms Bitcoin payment status; unpaid cohorts are moved to leak site (Telegram channel only, no traditional dark-web blog).
  • Broader Impact: Predominantly Latin-American small-to-medium businesses (commercial stores, dental labs, accounting firms). Several cooperativa bancária networks in Paraná and Minas Gerais reported losses ≈ 2.3 million BRL (~$450 k USD) during July-Aug 2022. The perpetrators recycle infrastructure from older Phobos affiliates, demonstrating cross-family code reuse; indicators-of-compromise therefore overlap significantly with former Phobos “.eking” or “.mallox” campaigns.