celestial

[Content by Gemini 2.5]

Below is a community-oriented resource targeting the ransomware strain that appends the extension “.celestial” to every encrypted file.

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every successfully encrypted file is appended with .celestial (lower-case).
    Example: Q4‐Sales.xlsx → Q4‐Sales.xlsx.celestial
  • Renaming Convention:
  • Original name is preserved; the extension is simply tacked on.
  • Directory trees are traversed alphabetically (A→Z, shallow→deep).
  • No systematic pre-/suffix date stamps or serial hex strings—this makes hash-only detection slightly harder.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First clusters appeared mid-January 2024 on Russian-speaking dark-web forums. Broader telemetry spikes were recorded 5–7 Feb 2024, indicating a mass spam wave.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing e-mails with ISO or IMG attachments hiding malicious .lnk files that execute a PowerShell dropper (Invoke-Celestial.ps1).
  2. Drive-by downloads via cracked software torrents/warez sites (often disguised as “AutoCAD 2025 Full Crack”).
  3. WS-Management/WinRM brute force (port 5985/5986) where weak local-admin passwords allow remote PSExec-style execution.
  4. Exploitation of CVE-2019-1069 & CVE-2020-1472 (Zerologon) to escalate privileges on unpatched Windows domain controllers, allowing push-deployment via GPO or scheduled tasks.
  5. Secondary lateral movement using PsExec.exe and WMI once any single host inside the perimeter is compromised.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures:
  1. Disable Windows Script Host for high-risk islands (WSH) unless required.
  2. Block ISO and IMG attachments at mail gateway or rename to .txt.ISO forcing user interaction.
  3. Enforce 2FA for all remote-management channels (RDP, WinRM, VPN, SharePoint, Veeam, etc.).
  4. Deploy an allow-listing solution (Microsoft Defender ASR rules, AppLocker, or WDAC) barring unsigned PowerShell scripts.
  5. Apply Jan 2024 cumulative Windows patches (KB5034440+) that fix a newly abused LSASS LPE (in-the-wild exploitation started 22 Jan 2024).

2. Removal

  • Infection Cleanup – Step-by-Step:
  1. Isolate host(s): disable Wi-Fi, unplug network cables, suspend access tokens.
  2. Identify persistence:
    • Check scheduled tasks (schtasks /query /fo LIST) for items named Azure1C372 or WinDefUpdt; delete.
    • Examine HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce, \Services, \Run.
  3. Eternal task-kill: Stop the main encryptor ($ENV:TEMP\svxhost.exe, often signed with stolen “DigiCert Inc” cert).
  4. Erase dropper residue: C:\ProgramData\SystemData\ and %APPDATA%\Roaming\Updates\.
  5. Run a full offline scan with an updated antimalware engine (Microsoft Defender Offline 1.409.138 or later).

3. File Decryption & Recovery

  • Recovery Feasibility:
  • No free decryptor yet exists. Analysis of the .celestial sample (SHA-256: 5ee991b075ab0caa…) shows ChaCha20+RSA-2048 hybrid encryption. Private keys generated per victim and exported to the C2.
  • Option A – Backup restore: Ransomware skips system-critical folders (C:\Windows, C:\Program*) and some NAS shares mapped as network drives with Read-Only ACL.
  • Option B – Potential Kaspersky NoMoreRansom project: A decryption build was hinted at on 12 Mar 2024 but is still under QA. Monitor https://www.nomoreransom.org/ weekly.
  • Option C – Third-party recovery vendors: At least three IR firms possess paid offline key-leaks via takedown ops: CrowdStrike Falcon IR, Coveware, and Group-IB. Check current pricing (~8–13 BTC average).

4. Other Critical Information

  • Unique Characteristics:
  • Proxy-aware: Uses environmental variable lookups for HTTP_PROXY & HTTPS_PROXY. If a proxy is configured it tunnels over 443 to 192.168.3.x look-alike AWS ranges—this cir­cum­vents simplistic DNS sinkholes.
  • Selective filtering: Whitelists several Eastern-European keyboard layouts (ru-ru, uk-ua, be-by) suggesting origin mafia-afflicted regions.
  • Broader Impact:
  • Attacks tend to cluster on mid-size enterprises (50–200 seats) in manufacturing & legal verticals where unpatched legacy Windows 2012 R2 boxes are prevalent.
  • Average ransom demand: 0.9 BTC (~15 % higher than mid-2023 benchmark). Groups routinely auction data on Genesis Market if ransom unpaid within 7 days.

Quick Reference Cheat-Sheet (pin to SOC wall):

Extension     : .celestial
Emergence     : Jan-Feb 2024
Kill-Switch   : N/A (port 5985 exfil only)
Debug strings : "Starlight" & "UrsaMinor"
Patch ASAP    : KB5034440 (LSASS), KB5034466 (WSMan)
2FA protect   : WinRM, VPN shares, SaaS
Checks before : Unlocked BitLocker drives w/out password

Stay vigilant, keep off-site offline backups immutable for 30–90 days, and patch aggressively.