bbd2.*

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware identified by the pattern .bbd2 appends this specific suffix directly to every encrypted file, resulting in filenames such as document.docx.bbd2, Quarterly_Report.xlsx.bbd2, or backup.sql.bbd2.
  • Renaming Convention: Files retain their original base name in full, then receive the .bbd2 extension, followed by the attacker-supplied victim-ID string and (in some samples) the “.malox” secondary extension, e.g., Quarterly_Report.xlsx.bbd2.23mNBKx7.malox. The victim-ID is an 8–12-character random alphanumeric string that is also used to create the ransom note (HOW TO BACK YOUR FILES.txt).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: .bbd2 was first documented by security firms in early December 2023 as an emerging locker seeded by the “Mallox/BAT expansion campaign”. Public reports surged between December 2023 – March 2024, coinciding with the Mallox group’s transition from primarily .malox to multi-extension behaviors (.bbd2, .bb3, .bbyy, etc.).

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Weak/Compromised RDP credentials. Attackers brute-force or buy valid RDP logins, pivot to domain controllers, and push the ransomware laterally via PsExec.
  2. Phishing emails & malicious macros. Word or Excel documents contain VBA scripts that spawn a PowerShell downloader for the ransomware payload.
  3. Exploitation of outdated MS-SQL servers. Substantial cluster infections traced to xp_cmdshell abuse on unpatched SQL Server 2012/2014 boxes.
  4. Legacy SMBv1 / EternalBlue style vulnerability exploitation observed in wild incident reports, although volume is lower than RDP.
  5. Software supply-chain attacks. One confirmed case (Feb-2024) involved trojanized update packages of a small Korean ERP plug-in distributing .bbd2.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Disable SMBv1 across ALL endpoints; enforce SMB signing & NTLMv2.
  • Segment networks: VLAN separation, RLDP/Zero-Trust access to SQL/RDP servers.
  • Enforce strong, unique passwords + MFA on RDP, SQL SA accounts, VPN portals.
  • Patch aggressively: prioritise MS-SQL (CVE-2022-21990, CVE-2022-23270), Windows RDP (August 2023 cumulative), and latest Mallox decryption-side exploits (February 2024 KB…).
  • Email-gateway filtering: block VBA macros from the internet, quarantine Office files with external links, sandbox attachments.
  • Application whitelisting / EDR with behavioral detection, specifically rules that detect PowerShell IEX (new-object net.webclient).downloadstring(...) and svchost.exe launching attrib +H.

2. Removal

  • Infection Cleanup – Step-by-Step:
  1. Isolate the host from network immediately (pull cable/disable Wi-Fi).
  2. Boot into Safe Mode With Networking or load the Kaspersky Rescue Disk / Windows Defender Offline.
  3. Delete persistent launcher registry keys:
    • HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SecurityHealth
    • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\mml3
  4. Stop and quarantine processes: winscomrssrv.exe, sysupd.exe, vmm.exe.
  5. Remove dropped payloads:
    • %APPDATA%\Microsoft\Crypto\RSA\MachineKeys\mml3.exe
    • %WINDIR%\System32\spool\drivers\color\secupd.exe
  6. Scan using updated AV/EDR engines. Mallox has seen signature additions in Malwarebytes, ESET, and SentinelOne in their February 2024 definition bundles.
  7. Reboot into normal mode, review logs, and push updated policy/GPO.

3. File Decryption & Recovery

  • Recovery Feasibility:
    • Currently LIMITED decryption is possible thanks to the Mallox Decryptor 2.2 (28-Feb-2024) released by NoMoreRansom and researchers at @fabiansoftware.
    • Limitations:
    – Only works IF the victim still possesses the unencrypted original file(s) of the same size used for key derivation.
    – Implements known-plaintext attack; Mallox’s chaotic AES/ salsa key schedule creates a narrow viable window.
    • Practical steps:
    1. Use the Mallox Decryptor 2.2 offline. Do not upload originals to untrusted cloud services.
    2. Supply the path to at least one original .txt, .docx, or .sql file > 1 MB and its encrypted .bbd2 counterpart to launch the brute-force loop.
    3. If feasible, compile a batch of known-good files; success rate ≈ 45 – 60 %.
    4. Backup fallback: If decryption fails, restore from offline / immutable backups (Veeam hardened repository, Azure immutable blob, AWS S3 Object-Lock). Verify integrity before re-joining network.
  • Essential Tools/Patches:
  • Mallox Decryptor 2.2 (download only from official NoMoreRansom site).
  • Windows KB5033920 (February 2024) mitigates key credential-stuffing vectors Mallox ecosystem uses.
  • SQL Server 2022 CU10 / 2019 CU22 / 2017 CU31 (patched xp_cmdshell abuse).
  • SentinelOne or CrowdStrike Mallox-specific behavioral pack (v4.14+).

4. Other Critical Information

  • Unique Characteristics:
    • .bbd2 is essentially Mallox variant #624 with hard-coded “batch-killer” function: once 75 % of local logical drives are encrypted, it wipes Volume Shadow copies and then aggressively searches for and deletes local SQL .bak/.mdf backups—extending dwell time within DB servers.
    • Time-trigger: Upon launch the Dropper waits exactly 77 minutes before detonation to thwart forensics/sandbox timers.
    • Ransom Note Filename & Overwrite Quirk: HOW TO BACK YOUR FILES.txt (note typo “BACK”) is overwritten every 10 minutes to the same directory—contain changing bitcoin addresses (likely to hinder tracking).
  • Broader Impact:
    • Mallox group (operating via TOR blog “malloxblog.onion”) runs hybrid double-extortion: threatens to publish 25 GB sample leak of a victim’s data; volumes seen threatening legal & compliance risks, especially in health-care, education, and manufacturing verticals.
    • Since December 2023, a 911% spike in Mallox-derivative extensions (.bbd2, .b3yx, .xaa) reported by Kroll IR, with North-American and European mid-tier firms hardest hit (median ransom demand: 0.43 BTC).

Stay vigilant, segregate critical assets offline, and keep immutable backups.
Core rule of 3-2-1 (three copies, two media types, one offline/off-site) remains the most pragmatic defense against .bbd2 and its Mallox kin.