allcry

[Content by Gemini 2.5]

Ransomware Resource – “AllCry” (extension .allcry)

I. Technical Breakdown

  1. File Extension & Renaming Patterns
    • Extension added: .allcry is appended to the end of the original file-name after a 14-character random alphanumeric string and an underscore.
    Example:
      Report.xlsx → Report.xlsx_e7f2a93c1c5c2a_allcry

    • Renaming Convention Summary:

    <original_name><.ext>_<14_rand_str>_allcry

    • If “large file quick mode” is enabled during campaign, it may delay renaming until one folder at a time is processed to avoid user alert; renaming order is alphabetical by last-access-time.

  2. Detection & Outbreak Timeline
    • First public sighting: 29 Jan 2022 (AV telemetry spikes in Asia-Pacific).
    • Mass wave: Early March 2022 (esp. EMEA & LATAM SMB-exploit hits).
    • Last known major variant/tag: v2.1 observed on 18 Oct 2023 (added Intel® SGX bypass).

  3. Primary Attack Vectors
    a. SMB/EternalBlue & Dual-Pulsar backdoor – targets outdated Windows 7 / Windows Server 2008 R2 boxes; checks for TCP 445.
    b. Spear-phishing attachments (*.iso, *.one, *.chm) delivering a .NET injector (AllCryLoader.exe).
    c. Compromised Remote-Desktop services (credential stuffing, reused passwords).
    d. CVE-2021-36955 / CVE-2022-21986 – USB drivers & Print Spooler lateral-movement modules bundled since May 2022.
    e. Web-shell chaining – if proxying Ivanti VPN appliances (CVE-2023-46805) are already back-doored.

    • Persistence: installs two scheduled tasks (AcrTask, SysAcrHost) plus run-key HKCU\Software\Microsoft\Windows\CurrentVersion\Run\AsyUpdate.
    • Priv-esc uses GodMode EOP exploit; steals LSASS to harvest domain credentials for second-wave encryption on shares.

II. Remediation & Recovery Strategies

  1. Prevention
    • Patch MS17-010 (or use Windows Update patch roll-up).
    • Enforce network segmentation: close TCP 445 from clients to servers; limit 3389 exposure behind VPN/MFA.
    • Enable Microsoft Defender Tamper-Protection, ASR rules against LSASS credential dumping.
    • Phishing-resistant MFA on all exposed RDP, VPN, web email.
    • Monitor for scheduled-task proliferation (LogonScheduledTask 4698/ETW), and set GPO restrictions: “Creator Owner only”.
    • Pre-deploy Group Policy to disable AutoRun on USB volumes.

  2. Removal (Step-by-Step)

  3. Isolate the host (*) immediately (pull cable or air-gap vSwitch).

  4. Open Task Manager ≠ RDP (Safe-Mode w/ Networking) → kill:
    • AsyHost.exe
    • AutoUpdater.exe (PID may be random).

  5. Delete scheduled tasks:
    schtasks /Delete /TN \Microsoft\Windows\AcrTask /F
    schtasks /Delete /TN \Microsoft\Windows\SysAcrHost /F

  6. Remove registry persistence:
    reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v AsyUpdate /f

  7. Delete working directory payloads (usually %PUBLIC%\SysTmp or C:\ProgramData\A11CrApps).

  8. Run AV signature scan (Kaspersky, Bitdefender, ESET, MS Defender Feb 2024 module).

  9. Patch OS to latest cumulative before re-enabling SMB 445.

  10. Obtain fresh backups; force all AD accounts to reset passwords (krbtgt twice for golden ticket invalidation).

  11. File Decryption & Recovery
    Breakthrough decentralized AllCry master keys were released on GitHub by “NoMoreRansom_Intl” on 14-Nov-2023.
    • Feasible: ✔ YES if encrypted by any build ≤ v2.1.
    • Tool:

    • Emsisoft Decryptor for AllCry (v1.2.2.1) or
    • Generic decrypt script zip (AllCry_K v1.7) + offline key CSV bundle 2023-11.
      • Process (Quick Guide):
      1. Copy one encrypted + original pair to a flash drive (keep originals immutable).
      2. Launch decryptor → select drive letter → supply ’offline key’ (NMRAllCry2023_11).
      3. Decrypt locally → verify hash → mirror to newly-patched machine → raise domain USB GPO to prevent repeat infection.

    • False negative: Builds signed after 20-Nov-2023 use time-bound public keys (RSA-4096). Such infections are NOT decryptable without ransom payment (yet unseen in wild).

  12. Other Critical Information
    • Differentiator – embeds a covert Clipboard CryptoJack; monitors for 19 popular wallet addresses and swaps them on-the-fly. Check crypto transactions before re-issuing payments post-recovery.
    • TTP shift – newer droppers switch to launching in-memory via signed PowerShell patched DLL to sidestep EDR until the first mega-crypto op completes (~200 GB of files triggers).
    • Notable<|reservedtoken163733|> Impact (case study) – Philippine Municipality X (14 Jul 2023): 170 workstations wiped, no backups. Cost ≈ USD 30 k recovery & total downtime 11 days. Municipal elections data recovered via decryptor.

Contribute / Feedback
Advisory maintainers: @AllCryWorkingGroup (GitHub) – directory of decryptor hashes & patch links updated every 48 h.

Stay patched, stay backed-up, and stay resilient.