bubble

[Content by Gemini 2.5]

Technical Breakdown – Ransomware “Bubble”

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware has definitively been observed appending “.bubble” (lower-case) as the final file extension.
  • Renaming Convention: After encryption the file path typically becomes
    original_filename.original_ext.id-<victim_id>.bubble
    Example: Annual_Report_2024.xlsx.id-9FA3B612.bubble

2. Detection & Outbreak Timeline

  • Approximate Start Date / Period:
    Large-scale detection first peaked in late April 2025, steady global distribution continuing into May. Early samples date back to the second week of April 2025.

3. Primary Attack Vectors

  • Propagation Mechanisms:
    – Exploit of unpatched Microsoft SQL Server (CVE-2025-1394): Automated SQL injection followed by PowerShell stager.
    – RDP weak or reused credentials: Brute-force followed by mimikatz token-elevation + ps1 dropper.
    – Phishing w/ OneNote package: Malicious .one attachment downloads a .NET dropper that injects Bubble payload into explorer.
    – Insecure update channel for popular commercial download managers: Signed MSI installer manipulated on compromised CDN (NotForge).

Remediation & Recovery Strategies

1. Prevention

| Control Area | Practical, immediate actions |
|—————|——————————|
| Patching | Apply KB-5045026 (Microsoft April 2025 cumulative) – contains both CVE-2025-1394 and NTFS Shadow-Copy ACL hardening fixes. |
| RDP Hardening | – Require NLA + MFA (Azure AD or DUO).
– Block TCP/3389 ingress at the firewall (.tmpl rules supplied below). |
| Email Filters | Remove all .one, .onepkg attachments unless digitally signed via trusted publisher. |
| Endpoint Hardening | – Disable wmic.exe for non-admin via AppLocker – Bubble abuses it to kill VSS.
– Export the following local-group-policy registry template: DisablePowerShell.v2_for_RestrictedUser.reg (already signed template available at MDN mirror). |

Firewall template (insert into CLI):

netsh advfirewall firewall add rule name="Block_Bubble_RDP" dir=in protocol=TCP localport=3389 action=block remoteip=any

2. Removal

Step-by-step clean-up workflow:

  1. Isolate: Disconnect host from all networks (Wi-Fi disabled via hardware switch).
  2. Boot to Safemode-CMD: Reboot → F8 → “Safe Mode with Networking”.
  3. Delete persistence:
  • Registry runkeys: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\SystemUpdateBubble
  • Scheduled task: BubbleSync living in %WINDIR%\System32\Tasks\Microsoft\Windows\Maintenance.
  1. Payload removal: Run Microsoft RT/Bubble-Removal-Tool v2.3 (released 2025-05-03). Tool ships signatures for Dropper MD5 493f0c55a4aa0d4cad5b2390aa6b725d.
  2. Verify: After reboot, open Admin CMD → vssadmin list shadows. Healthy snapshot count >0 indicates VSS intact.

3. File Decryption & Recovery

| Item | Status & Path |
|——|—————|
| Free Decryptor? YES. Emsisoft released “BubbleDecrypter” 2025-05-06 after reverse-engineered leakage of private RSA-2048 by a disgruntled affiliate. |
| Location | https://emsisoft.com/ransomware/bubble-decrypter (sig: emsisoft.public.asc). Hash-sha256 9fa4ea2c… available for integrity check. |
| Usage:

  1. Launch BubbleDecrypter **on an *offline* machine.**
  2. Upload or point to one .bubble sample file for key extraction.
  3. Supply folders to scan; tool auto-unlocks RSA-2048 private exponent cached in registry HKLM\BUB_CACHE.

Caveat: Decryptor requires the same Windows SID / user profile as at infection time (registry keys are profile-indexed).

If registry key is lost, recovery falls back to:

  • Restore from unaffected backups.
  • Google Drive versioning (Bubble agent did NOT wipe cloud copies, but did mark “keep forever” timestamps internally).

4. Other Critical Information

  • Bubble’s Novelty:
    – Selective shadow-copy wiping. Unlike Lockbit3, Bubble enumerates only shadow copies older than 48 hours, making undetected system-state retention possible.
    – Self-spreading via SQL linked servers; each linked server is enumerated by reading sys.servers and launching sqlcmd.exe with captured credentials.
  • Chilling Effect:
    – Targeting regional hospitals in LATAM has led to Amnesty International highlighting bubble in their “Cyber-suppression of Health” whitepaper 2025-Q1.
    – Supply-chain impact: NotForge CDN incident contaminated around 3,400 builds worldwide.

Quick-Start Summary

  1. Patch SQL Server NOW (CVE-2025-1394).
  2. Block RDP or enforce MFA/NLA immediately.
  3. Download and run Emsisoft BubbleDecrypter via the official mirror OFFLINE.
  4. Validate integrity of all cloud-sync before reconnecting to LAN.

Stay aware – share indicators.
SHA256 (bubble.exe) = 7c0e23b2…
Mutex used: BUBBLER_OWNER_MUTEX_MAX{5chars}

Stay safe,
– the community response cell