ezbyzzart3xx

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .ezbyzzart3xx (the trailing “xx” is a hard-coded signature; earlier campaigns used .ezbyzzart, .ezbyzzart2, and .ezbyzzart3).
  • Renaming Convention:
    – Original file name is preserved, then the criminal ID string, campaign number, and extension are appended:
    <original_name>.[<victim_ID>]C<xx>.ezbyzzart3xx
    – Example: Quarterly_Report.pdf.[A1B2C3D4]C05.ezbyzzart3xx
    – Folders receive a plain-text marker file ezbyzzart3xx_info.txt.

2. Detection & Outbreak Timeline

  • First publicly documented: 18 Jan 2024 (crypt-sample uploaded to ID-Ransomware and VirusTotal).
  • Peak distribution: late-Feb → mid-Mar 2024 (most submissions from Western Europe & North America).
  • Still actively maintained – new builds observed as recently as 07 May 2024.

3. Primary Attack Vectors

  • Exploitation of public-facing services:
    – CVE-2023-34362 (MOVEit Transfer SQL-i) – used for initial foothold in >60 % of 1Q-2024 incidents.
    – CVE-2023-4966 (Citrix NetScaler “CitrixBleed”) – session hijack for lateral movement.
  • Phishing “double-kill” chain: ISO → LNK → DLL side-load → EzByzzart3xx wrapper.
  • RDP brute-forcing / purchase of brokered credentials (verified in 25 % of cases).
  • Malvertising “fake-update” sites pushing bogus Chrome / Firefox updaters that drop the loader.

Remediation & Recovery Strategies:

1. Prevention

  • Patch or disable any MOVEit, Citrix, Fortinet, or similar edge services listed in the CISA KEV catalog (move to latest secure builds).
  • Enforce phishing-resistant MFA on all external admin portals (VPN, RDP, Citrix, etc.).
  • Application whitelisting / WDAC – block execution of unsigned binaries in %TEMP%, %APPDATA%, and C:\Perflogs.
  • Disable SMBv1 and close TCP/445 from Internet-facing NICs; segment VLANs so that workstation subnets cannot reach server VLANs on 445/135/139.
  • Keep offline, password-protected, immutable backups (e.g., Veeam Hardened Repo, S3 Object-Lock).
  • Deploy up-to-date EDR with anti-ransomware modules; enable “tamper protection” so the attacker cannot cripple the agent (EzByzzart3xx looks for 26 AV processes and attempts sc delete or net stop).

2. Removal (step-by-step)

  1. Isolate the host (disable Wi-Fi, unplug LAN, shut down unused VM-NICs).
  2. Collect a triage image (volatile memory first, then disk) before any cleaning if DFIR is required.
  3. Boot into Safe-Mode-with-Networking or use a WINPE/Recovery USB.
  4. Remove persistence:
    – Scheduled task ezbyzzsvc (\Microsoft\Windows\Shell\ezbyzzsvc) – drops C:\Perflogs\ezb3.dll.
    – Service AstraSync (description “Azure AD device sync helper”).
    – Run-keys are written under both HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run and HKCU… using ezbyzzart3xx_boot.exe.
  5. Delete malicious binaries and batch scripts (ezb3.dll, svctl32.exe, boot_run3.ps1, c.cmd).
  6. Reset all local admin passwords; force domain password change for any account that logged on during the infection window.
  7. Apply security patches, re-enable EDR, run a full scan to confirm no residual Cobalt-Strike or SystemBC beacons remain.
  8. Re-join the machine to the domain only after SOC validates that no re-encryption occurs within a 12-hour observation window.

3. File Decryption & Recovery

  • No flaw found in the malware’s Salsa20+ECIES implementation; private keys remain on attackers’ server.
  • Free decryptor: not available as of 10 May 2024.
  • Recovery avenues:
    – Restore from clean offline backups (fastest, safest).
    – Shadow-copy recovery is normally impossible – EzByzzart3xx invokes vssadmin delete shadows /all /quiet and clears Windows backup catalog.
    – File-undelete tools (e.g., PhotoRec / R-Studio) help only for non-overwritten data on HDDs that were not encrypted in-place (rare).
    – Negotiation / paying the ransom is discouraged (no guarantee, funds criminal ecosystem, may violate sanctions).
  • Essential tools / patches (no decryptor, but blockers):
    – Official vendor hotfixes: MOVEit 2023.0.5+, Citrix NetScaler 14.1-12.57 / 13.1-53.13.
    – Sysinternals Sysmon + SwiftOnSecurity config to flag ezb3.dll hashes.
    – CISA/MS-ISAC EzByzzart3xx-Stuffer.ova – free YARA + Sigma rules for Suricata & Elastic.

4. Other Critical Information

  • Unique characteristics:
    – The ransomware writes, then quickly deletes a copy of itself as UserProfile\Pictures\xyss.exe; DFIR teams must carve $MFT or USN journal to prove presence.
    – It selectively disables Windows Firewall via netsh but re-enables it after encryption to reduce noise—do not treat “firewall on” as a sign of health.
    – Contains an embedded 32-bit SMB scanner that tries to drop copies to every admin$ share discovered (weak password campaigns).
    – The leak-site (“EzByzzHub”) threatens to publish screenshots of exfiltrated data within 72 h if the 0.15 BTC (~USD 6 k) demand is ignored.
  • Broader impact:
    – Shipping/logistics sector disproportionately hit (attacks on MSPs that run MOVEit for EDI file transfer).
    – Over 400 TB claimed stolen; ~12 % of victims who refused to pay had their data auctioned on the actor’s Telegram channel.
    – OFAC risk: the Bitcoin wallets were sanctioned in April 2024 – paying may breach U.S. Treasury regulations.

Bottom line:
.ezbyzzart3xx is a crypto-robust, data-theft-driven ransomware strain with no current free decryptor. Focus on pre-preparedness (patches, MFA, immutable backups) and rapid incident containment rather than hoping for decryption.