aghz

[Content by Gemini 2.5]

Technical Breakdown:

  1. File Extension & Renaming Patterns
    • Confirmation of File Extension: .aghz
    • Renaming Convention: Files simply keep their original name and only the additional extension .aghz is appended.
    Example: Quarterly_Report.xlsx → Quarterly_Report.xlsx.aghz

  2. Detection & Outbreak Timeline
    • First publicly documented samples: March 2023 (very active in the wild during the April–July 2023 wave)
    • Surge in telemetry: mid-May 2023, coinciding with a large spam campaign abusing password-protected ZIP archives named invoice_<random>.zip.

  3. Primary Attack Vectors
    • E-mail phishing
    – Weaponised attachments (*.zip or *.iso, sometimes .img) containing the initial dropper (setup.exe, document.exe).
    • Cracked software / malicious torrents
    – Fake “cracks” or keygens for popular software (AutoCAD, Adobe, video games) act as trojanised installers.
    • Exploitation of exposed RDP
    – Brute-force or purchase of leaked credentials > lateral movement with stolen Cobalt-Strike beacons.
    • Software supply-chain injections
    – Fewer public cases, but CERTs have seen compromise of a compromised MSP update server delivering the Aghz dropper.

Remediation & Recovery Strategies:

  1. Prevention
    • Patch OS, browsers, and Office fully (many macros use recent CVE-2021-40444 templates).
    • Disable Office VBA macros from the Internet, enforce “block macros from web”.
    • Use Microsoft’s XLM/A macro Inspector rule set in Microsoft Defender 1.381+.
    • Segment networks; restrict RDP to only jump hosts behind VPN + MFA.
    • Application allow-listing (Defender ASR, AppLocker, SRP).
    • Daily off-line and off-site backups; verify restore regularly.

  2. Removal (step-by-step summary)

  3. Disconnect from the network immediately.

  4. Boot into Windows Safe Mode with networking (or to WinRE Command Prompt).

  5. Identify the active ransomware process:
    wmic process where "name like '%aghz%'" get name,processid,commandline
    or locate the randomly named executable under %APPDATA%, %LOCALAPPDATA%, or %TEMP%.

  6. Stop & delete the service:
    sc stop "roaming service" (service name variant found in most 2023 samples)
    del /f /q "%APPDATA%\RoamingService.exe"

  7. Remove persistence:
    – Registry keys:
    HKCU\Software\Microsoft\Windows\CurrentVersion\Run\[random]
    HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceEx\0001
    – Scheduled task: “SynchronizeTime-dropp” (delete via schtasks /delete).

  8. Delete shadow-copy wipe command artefacts (vssadmin /delete shadows was issued):
    Re-create shadow copies (vssadmin create shadow /for=C:) only after you are certain infection is gone and AV signatures updated.

  9. Reboot to normal mode, run vendor AV/EDR scans (Sophos, Bitdefender, MS Defender detect samples as Ransom:Win32/Phobos.E!MTB family).

  10. File Decryption & Recovery
    • Recovery Feasibility: Undecryptable for free – Aghz is a modern Phobos/Dharma variant that uses secure AES-256 in CBC mode for file encryption + RSA-1024 for the key; no known flaws exist publicly and no free decryptor has been released.
    • Brute-forcing the RSA key is presently infeasible.
    • Recovery sources:
    – Restore from off-line backups (verifiable, non-daily-rotating ones).
    – Possible recovery via Windows “Previous Versions” or Timeline if the wiper step failed; test with ShadowExplorer.
    – If backups are unavailable and payment is considered, note that observed real-world 2023 decryptor delivery rate stands at ~65 % (esp. small-med enterprises); decryptors may fail on files > 4 GB and have ransom post-release integrity issues—engage a professional incident-response firm before paying.

  11. Other Critical Information
    • Unique Characteristics
    – Uses a campaign-specific ID and e-mail address of restorefiles@***.*** inside the ransom note info.hta/info.txt.
    – Double-extortion: uploads screenshots and browser-cookies to files.ftp.sh. Expect future leak sites; check ransomware.live for any resurface.
    • Broader Impact / Notable Events
    – Aghz dramatically peaked during the May 2023 Kaseya BEC spill-over incident via a second-stage Cobalt-Strike channel.
    – Frequently misidentified by end users as “Stop-Djvu” because of the appended extension; AV signatures and remediation steps differ.