dwbiwty

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .dwbiwty (upper-case .DWBIWTY is also seen, but lower-case is default).
  • Renaming Convention:
    – Original name → <original_name>.dwbiwty (no email, ID, or campaign tag appended).
    – Folders receive a plain text dropped note README.txt; individual files are NOT re-titled beyond adding the extension.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Earliest reliable submissions to ID-ransomware & VirusTotal appeared 2024-02-09. Surge of enterprise alerts observed mid-February → March 2024. (No earlier builder or v1 artefacts found, so threat is ≤ 6 months in the wild.)

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing e-mail carrying ISO / ZIP / IMG lures that contain a .NET loader (“SwiftDownloader”) → executes Rust-based payload (dwbi.exe).
  2. External DMZ exposure / brute-forced RDP → Cobalt-Strike BEACON → manual deployment of dwbiwty.exe -a (“all drives” switch).
  3. Exploitation of un-patched MS-SQL servers (sa account with weak password) → xp_cmdshell drop + execution.
  4. Living-off-the-land: uses vssadmin delete shadows /all, bcdedit to disable recovery, net stop for SQL, Exchange, QuickBooks before encryption.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures:
    ☐ Block ISO / IMG at the mail-gateway; disable Windows ability to auto-mount ISO via GPO.
    ☐ Enforce 14-char+ passphrase + account lock-out for RDP; place RDP behind VPN + MFA.
    ☐ Patch: Microsoft Feb-2024 cumulative update (CVE-2024-21437 SQL RCE vector); else at minimum disable xp_cmdshell.
    ☐ Application whitelisting / WDAC – the main payload is UNSIGNED dwbiwty.exe (sha256: 4b75…c8e9) and easily caught.
    ☐ EDR rule: Alert on vssadmin.exe delete shadows, bcdedit /set recoveryenabled No, and on creation of README.txt in > 20 directories/minute.

2. Removal

  1. Power down estate → isolate one patient-zero to perform forensics.
  2. Boot from WinPE / Linux live-USB → back-up encrypted data plus the ransomware binary (needed if free decryptor later appears).
  3. Install OS to clean media or re-image from known-good gold-build.
  4. Manually delete scheduled tasks \Microsoft\Windows\DWBIWtyUpdate and service DWBI助手 if present.
  5. Patch, re-join domain, re-install apps, restore data only AFTER verifying decryptor or clean backups.

3. File Decryption & Recovery

  • Recovery Feasibility (2024-07): No flaw found → DECRYPTION WITHOUT KEYS IS IMPOSSIBLE.
    – Uses Curve25519 + ChaCha20-Poly1305; private key is RSA-2048 encrypted & uploaded to C2 only.
    – Author’s decryptor price observed: 0.18 BTC (≈ US $5 900) with a 72-hour timer.
  • Free options:
    ✓ Check <id>.killswitch file (created in %TEMP%); if your sample failed to reach C2 it sometimes embeds an OFFLINE key—upload pair to <anything>.dwbiwty + README.txt to https://id-ransomware.malwarehunterteam.com – if result changes to “known offline key”, a free tool may be published.
    ✓ ShadowCopy seldom survives, but run winfr (Windows File Recovery) or photorec to carve non-encrypted copies from free space.
  • Essential Tools/Patches:
    – Latest MS-SQL cumulative update (KB5034675).
    – MSERT (Microsoft Safety Scanner) v1.0.4001+ already detects as Ransom:Win32/Dwbiwty.A.
    – Keep 3-2-1 backups, immutable (Veeam Hardened Repo, Azure LRS with delete locks, AWS S3 Object Lock).

4. Other Critical Information

  • Additional Precautions / IOCs:
    – Mutex DwbiwtyIsRunning2024 prevents duplicate runs – its absence can be a crude “vaccine” (don’t rely on it).
    – Listed e-mail for negotiation changed four times: [email protected], [email protected], [email protected], [email protected] – always verify the note in YOUR folder; copy-paste errors are common.
    – Drops post-exploitation script kill.bat that disables Windows Firewall; ensure GPO re-enables it automatically.
  • Broader Impact:
    Mid-tier ransomware, but encryption speed is high (Rust + ChaCha) – 100 k files ≈ 7 min. Main damage so far reported in APAC manufacturing & EU healthcare verticals. Because of simultaneous SQL-targeting + RDP outbreaks, total downtime averages 5 days for firms without cleanly segregated backups.

Stay alert, keep those backups offline, and remember: with .dwbiwty the only free “decryptor” available today is the one you built yourself before the attack.