crashed

[Content by Gemini 2.5]

Resource: “crashed” Ransomware – Community Threat Brief

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed File Extension: .crashed
  • Renaming Convention:
    Victim files receive a three-part pattern that always ends in .crashed.
    Example: Annual_Report_2024.pdf → Annual_Report_2024.pdf.id[XXXXXXXX].[[[email protected]](mailto:[email protected])].crashed
    The middle token is a 6–8-character hexadecimal victim-ID.
    The e-mail address is payment/contact information and can change per campaign.

2. Detection & Outbreak Timeline

  • First Observed: Small-scale telemetry hits began in late February 2021 (earliest underground marketing).
  • First Public Incident Reports: March–April 2021 – multiple MSSPs and regional CERTs flagged clusters targeting healthcare and manufacturing in EMEA.
  • Surge Events:
    – 7 May 2021: Widespread affiliate push tied to RIG and Fallout exploit kits.
    – August 2022: Notable uptick alongside malvertising campaigns on fake browser-update sites.
  • End-of-Life: The core operator (Hive ransomware group) shut down infrastructure after 2022-11-AG-Ir (FBI-led) Operation, but .crashed binaries continue to be reused by spin-off affiliates as “OFFER-v2” builder.

3. Primary Attack Vectors

| Vector | Details |
|—|—|
| RDP/SSH brute force | Translation to PowerShell Empire via compromised SOHO gateways (default or weak credential sets). |
| Phishing (macro & OneNote) | Lures are fake courier notifications and payslips. Attachments are .docm, .xlsm, or .one files that drop a 32-bit .NET loader (.exe.tmp stage). |
| Exploitation of ProxyLogon (Exchange) | March 2021 wave leveraged CVE-2021-26855 to gain foothold before lateral LSASS dumping via Mimikatz. |
| Software supply-chain | Compromised update servers of two niche industry tool vendors (March 2022 attribution report by HP Talos). |
| Living-off-the-land | Post-initial access uses Microsoft’s own PSExec, certutil, bitsadmin, and WMI for lateral movement and file staging.

Remediation & Recovery Strategies

1. Prevention

  • Patch aggressively: Any endpoint or server touched by the above CVEs (Exchange, ProxyShell, Log4Shell).
  • Disable SMBv1 (prevents any possible EternalBlue re-use).
  • Deploy credential hygiene: Enforce strong unique passwords on RDP/SSH; block rdp port-forwarding at perimeter at minimum of IPS signatures.
  • Harden client applications:
    – Fully patched Office (blocks macro auto-run via Trust Center).
    – Disable OneNote automatic script execution (registry policy).
    – Use AMSI-aware AV (Defender ASR rules: “BlockOfficeCreateProcess” & “BlockPsExec”).
  • AppLocker / WDAC: Deny execution paths under %Temp%, %AppData%\Roaming, and %USERPROFILE%\downloads.
  • Offline/3-2-1 backups: Daily incremental + weekly offline. Write-once targets (Object Lock S3, ZFS send with snapshot immutability).

2. Removal

  1. Isolate: Disconnect host from network (both wired & Wi-Fi).
  2. Kill persistency: Boot into Safe Mode (or WinRE). Disable any scheduled tasks whose command line ends in svchostz32.exe, msupdater.exe, or rand64_com.exe.
  3. Delete malware artifacts (often in folders named \Users\Public\Libraries\AppDataDropx, \%TEMP%\7PS…, or \ProgramData\sdnomf\).
  4. Registry cleanup:
    HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\msupdater
    HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\DisableAntiSpyware (reset to 0).
  5. Full AV scan: Use bootable rescue disk (ESET SysRescue, Sophos Bootable AV).
  6. Permission audit: Change all local/domain admin accounts and rotate service accounts using affected credentials.

3. File Decryption & Recovery

  • Official Decryptor: After the takedown, the FBI obtained the master secret keys and released a free decryptor on 1 Feb 2023 via NoMoreRansom (tool: Hive_Crashed_Decryptor_v1.6.exe).
  • How to use:
  1. Confirm you have .crashed files and a ransom note named HOW_TO_RECOVER_FILES.crash.
  2. Download the decryptor (sig-verified, SHA256: a17197b9…).
  3. Run on a clean, fully-patched Windows machine.
  4. Point decryptor at the root drive (C:\ or network share).
  5. Operation can take 2-5 hours for > 1 TB of data; the tool can auto-backup originals before overwrite.
  • If no good backup: Decryptor does work, so prioritize disinfection instead of payment.
  • Non-windows targets (Linux ESXi): The group’s ELF binary appended .crashed to VM VMDKs. Same key material used—decryptor includes vmware.py script to handle thin-provisioned disks.

4. Other Critical Information

  • Encryption Behavior Snippet:
    – Hybrid encryption: ChaCha20 stream cipher wrapped with RSA-2048 OAEP for each file.
    – Selective file skipping: skips %Windir%, browser history, Bitcoin wallet folders (to leave emotion-evidence usable for payment psychology).
  • SonicWall RCE Integration: Latest builds attempt—if lateral movement hits—SonicOS CVE-2023-22242 for firewall takeover to drop VPN configs into the share.
  • Network Indicator of Compromise (IOC) beacon:
    – Hard-coded C2: https://crash-tools.top/api/auth
    – DGA fallback: Key plus current date in yyyyMMmd format, e.g., crash-xxxx-ddmm2024.top (Mitigation: sinkhole on DNS level).
  • Insider Threat notes: At least one MSP in LATAM provided initial access by forwarding attackers screenshots, reducing lateral-move effort to <30 minutes.
  • Regulatory Impact: U.S. HHS 405(d) added Hive/feeds into the “High Likelihood Healthcare Threat” memo (2023–2024), triggering additional HIPAA risk analysis requirements.

Closing Checklist

✅ Apply February 2023 security stack (MS patches + exchange-patch).
✅ Deploy decryptor on clean machine before re-joining domain.
✅ Validate backups from BEFORE infection (check metadata creation date).
✅ File mandatory incident report (GDPR, HIPAA, PCI) as applicable.

Stay vigilant, keep systems patched, and report any new Hive spin-offs using the .crashed moniker to your local CERT or FBI field office.