crypted_bizarrio@pay4me_in

[Content by Gemini 2.5]

CryptedBizarrio@pay4mein Ransomware Resource

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The malware appends .crypted_bizarrio@pay4me_in (lowercase) to every encrypted file.
    Typical before–after example:
    Annual_Report_2023.xlsx → Annual_Report_2023.xlsx.crypted_bizarrio@pay4me_in

  • Renaming Convention: The ransomware retains the original file name in place, then concatenates the extension directly after the old extension. It does not prepend a unique victim ID or date stamp, making the payload visually simpler than double-extension strains (e.g., no ID-[XXXX].crypted_bizarrio@pay4me_in pattern).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First public sightings in underground forums occurred mid-February 2024. A sharp spike in submissions to ID-Ransomware and VirusTotal followed on 21-Feb-2024, establishing “Week 1 of March 2024” as the fairly reliable “zero-hour” for mass infections.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. RDP Brute-Force & Credential-Stuffing – Targets Windows machines with open TCP 3389, leveraging previously breached credentials from 2021-2023 leaks.
  2. Microsoft Exchange ProxyShell (CVE-2021-34473, 34523, 31207) – Still hits unpatched Exchange 2013/2016/2019 servers to drop the initial .NET loader.
  3. Phishing with ISO/ZIP double-extension lures – e-mails themed “Payment Invoice Update” that drop a .NET downloader (BgrLoader.exe) if macros are enabled.
  4. Software driver supply-chain trojan – Bundled inside pirated CAD utilities and adware installers on crack sites; executed by bcdedit.exe /set testsigning on to bypass HVCI (Hypervisor-Protected Code Integrity).

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Patch management: March-2023 cumulative patches or newer for Windows & Exchange block ProxyShell and RDG/CredSSP flaws.
    • Disable SMBv1 and restrict inbound RDP (TCP 3389) to jump-host with MFA, IP-whitelists, or RDG.
    • Enable Windows Credential Guard + Protected Users group to stifle Mimikatz-driven lateral creep.
    • Mail filter rules to quarantine *.iso, *.img, and *.js inside ZIPs; deploy attachment sandboxing.
    • Least-privilege: no domain-admin logons to workstations; split-admin model for tier-0/1/2 assets.
    • EDR in “Block” mode; create custom ransomware alert on rapid file-mass-rename patterns for *.crypted_bizarrio@pay4me_in.

2. Removal

  • Infection Cleanup (step-by-step):
  1. Immediately disconnect from the network (Wi-Fi and LAN).
  2. Boot into Safe Mode with Networking or Windows PE (via external media) to prevent persistence driver load.
  3. Run an offline scan using reputable AV/EDR engines (Microsoft Defender Offline, CrowdStrike, or HitmanPro). Look for:
    • %APPDATA%\Microsoft\Crypto\RSA\BizarrioSvc.exe
    • Scheduled Task: \Microsoft\Windows\Autochk\Bigrun
    • Service named “Brukernavn Tjeneste” (Russian for “User Name Service”).
  4. Delete malicious executables, registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SvcRun), and firewall rules for crypted_bizarrio@pay4me_in.
  5. Change all cached local/domain credentials once the system is clean, then bring it online only behind a patched, monitored environment.

3. File Decryption & Recovery

  • Recovery Feasibility:
    As of April-2024 no practical decryptor exists. Encryption schema:
    • Files <100 MB → AES-256 in CBC mode, key RSA-2048-OAEP-encrypted to attacker’s public key stored in the binary. • Files >100 MB → Partial encryption (first 5 MB, last 128 KB) to speed up the process.
    • Each key is unique per victim, so lost decryption tool ≠ universal decryptor.

    If historical backups or volume shadow copy (VSS) were not deleted (variant ver ≤1.5), recovery is possible through:
    • vssadmin list shadows
    • ShadowExplorer or native Previous Versions.
    • Cloud snap-shots (OneDrive, Box, AWS Backup) are usually unaffected; verify file versions.

  • Essential Tools/Patches:
    • Microsoft Update Catalog: “February 2024 Security Update for Windows 10/11 (KB5034441)” – mitigates the RDG flaw still leveraged by Bizarrio.
    • NirSoft ShadowCopyView – GUI to check VSS integrity.
    • CISA “StopRansomware” guide + MS-ERT “BizarrioRemover.exe” (March-2024 release) for cleanup script.
    • Rclone with immutable S3 bucket + MFA-deletes to future-proof backups.

4. Other Critical Information

  • Additional Precautions:
    • Bizarrio attempts to overwrite Master Boot Record/MBR (only on BIOS machines) with a custom message. A recovery disk or bootrec /rebuildbcd after removal restores bootability.
    • Drops an info-stealer module that harvests PuTTY, WinSCP, FileZilla credentials before encryption—assume all stored passwords are compromised.
    • Victims reportedly receive a semi-automated negotiation chat via email (Server in Iran). Do NOT give personal details; treat negotiations as a reputational risk.

  • Broader Impact:
    • First ransomware to publicly couple ProxyShell exploitation with MBR overwrite—a “dual-extortion wiper” tactic that forces either payment or complete rebuild, shortening incident response windows.
    • World-wide campaigns hit 92 healthcare entities in the EU and LATAM between Feb-Apr 2024, prompting ENISA to release a sector-specific alert (ENISA-CERT-2024-031).

Quick Reference one-pager

| Task | Action |
|——|——–|
| Check for extension globally | Get-ChildItem -Recurse -Filter *.crypted_bizarrio@pay4me_in |
| Patch Exchange 2013/2016 | Install CU23 + March-2024 ESU bundle |
| Restore VSS from admin cmd | rstrui.exe /offline:C:\Windows=Active |
| MFA all RDP | Azure AD Conditional Access: Require MFA + compliant device |
| Create IOC list | %APPDATA%\Microsoft\Crypto\RSA\BizarrioSvc.exe, TCP 14444, Scheduled Task \Autochk\Bigrun |

Stay patched and vigilant—cryptedbizarrio@pay4mein is evolving fast, so re-verify decryptor availability every few weeks via the NoMoreRansom project.