blaze

[Content by Gemini 2.5]

Ransomware Profile: BLAZE (extension .blaze)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: [[filename]].blaze
    All encrypted files receive a single, six-letter suffix that is always lowercase.
  • Renaming Convention:
    – Original file name is fully preserved; the three-letter extension is appended immediately after the final dot (e.g., Project.docx → Project.docx.blaze).
    – Folder-level ransom notes (Restore_Files.txt) are dropped and left unchanged.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Wild samples were first uploaded to public malware repositories on 25 July 2023, with open-source hunters classifying it “living-off-the-land” ransomware rather than a new family. Subsequent campaigns peaked August—October 2023.

3. Primary Attack Vectors

| Vector | Typical Delivery Details |
|—|—|
| Phishing w/ Malicious Attachments | ZIP archives delivering ISO/IMG images (LNK → PowerShell “macro”-less chain) or MS Office docs abusing Follina (CVE-2022-30190). |
| Remote Desktop Intrusion | Credential-stuffing or brute-forcing exposed RDP/RDS hosts (port 3389) followed by manual loader deployment. |
| Software Vulnerabilities | Secondary usage of ProxyLogon (Exchange), Log4Shell (Java), and unpatched ConnectWise ScreenConnect (CVE-2023-34362) as initial footholds. |
| Living-off-the-Land Technique | The final binary is executed only in-memory via BRcLoader / Cobalt Strike; no artifacts are dropped to disk outside the ransom notes and encrypted data. |

Remediation & Recovery Strategies

1. Prevention

  1. Proximity controls: Disable/enforce NetBIOS/SMBv1 and block 445/3389 at network level unless strictly required.
  2. Patch aggressively: Deploy Exchange (May 2021), Windows (KB5015808 & newer), and ScreenConnect updates as soon as they become available.
  3. Email hardening: Enforce SPF/DKIM/DMARC, strip ISO/IMG from inbound mail, block LNK in ZIP files by policy or gateway.
  4. Least-privilege & credential hygiene:
    – Remove local “Administrators” from standard users.
    – Enforce MFA, especially on RDP/RDS and VPN.
  5. Endpoint hardening:
    – Disable PowerShell v2 (PowerShell 5.1+ defaulted on up-to-date Win10/11).
    – Enable Windows Defender ASR rules “Block credential stealing” and “Block untrusted & unsigned processes”.
  6. Backup & DR: 3-2-1 rule—3 copies, 2 media, 1 off-line/immutable (e.g., SAS-restricted Azure Blob or tape). Test restore BEFORE incident.

2. Removal (Infected Host, Bare-bones Workflow)

A. Disconnect & isolate NIC (pull cable/disable Wi-Fi) to stop encryption spread.
B. Boot into Safe Mode w/ Networking or WinRE (WinPE) to prevent persistence triggers.
C. Registry & Service Cleanup (elevated cmd): 

   reg delete HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run /v Blaze /f
   net stop "Blaze Service" 2>nul & sc delete "Blaze Service"

D. Scan with up-to-date AV/EDR (ESET, Kaspersky, or Windows Defender) in boot-time (Malware signature Ransom.Win64.Blaze).
E. Post-cleanup validation: Check Scheduled Tasks (HackTool/Loader via schtasks) & remove residual Cobalt DLL hosts under C:\Windows\System32\Tasks.
F. Stage restore: Do NOT re-join production network until logs are exported for IR and cleaners are confirmed 100 % gone.

3. File Decryption & Recovery

| Aspect | Status |
|—|—|
| Feasibility of Decryption | Currently IMPOSSIBLE for files encrypted after July 2023. No public decryptor exists; asymmetric RSA-4096 (Salsa20 stream) is soundly implemented. |
| Recovering Without Decryptor | 1) Authoritative backups (tests prior to infection date). 2) Shadow-copy absorber disabled in BLAZE—VSS often empty. 3) Explore cloud-sync snapshots (“Previous Versions”, OneDrive rewind). |
| Free Utilities | None. Treat any web-site advertising “.blaze decryptor” as fraud. |
| Essential Updates/Tools | Windows Offline Defender patches each stable + stable AV signatures (see above).

4. Other Critical Information

  • Unique Hallmarks
    – Minimum ransom note demand (~1 BTC) with working decryption test.
    – Uses open-source Salsa20 symmetric encryption, but the stream key is RSA-4096 wrapped—does NOT frustrate key recovery as poor entropy does in sloppier variants.
    – Timer in the GUI is hard-coded to 72 h; after that, files renamed to random .zzz and decryption site is unavailable (blazedec.top).
  • Wider Impact
    Healthcare & tele-service sectors in LATAM were disproportionately targeted Q4-2023 — possibly tied to a single affiliate operating from previous Conti playbook reuse. dma_locker was spotted sharing infrastructure nodes weeks prior, indicating possible umbrella RaaS scenario.

Checklist card:
☐ Disable SMBv1 & RDP
☐ Patch Exchange + ScreenConnect
☐ Enable BitLocker / LUKS full-disk + off-line backup
☐ Test restore today (CYA)