d3g1d5

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Files encrypted by the D3G1D5 ransomware are consistently given the new extension .d3g1d5.
  • Renaming Convention: Original file names remain intact with the new extension appended directly after the last dot
    e.g.
    2024_financial_report.xlsx → 2024_financial_report.xlsx.d3g1d5
    There is no additional ID string, email address, or random sequence added, which makes some backup-detection heuristics fail to flag the change immediately.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The strain was first publicly documented in mid-September 2023 after a spike of infections reported on ID-Ransomware and BleepingComputer forums. Initial activity seems to have begun on 12 September 2023 (UTC-3), centered around Brazilian and Portuguese victims.

3. Primary Attack Vectors

D3G1D5 uses a multi-channel delivery strategy:

| Vector | Technique & Example |
|—|—|
| Phishing Campaigns | Portuguese-language e-mails (Fatura_No_######.pdf.html) disguised as invoices from the Brazilian taxation authority. These HTMLs auto-download an .HTA which deploys the payload via mshta.exe. |
| Brute-force & Re-used Credentials | Persistent RDP scans on ports 3389 and alternate 33891. Dictionary lists contain leaked combinations (e.g., “adm2022”, “Funil2024!”). |
| Software Vulnerabilities | Post-exploitation lateral movement inside networks achieved through:
• ProxyShell (Exchange CVE-2021-34473, CVE-2021-34523, CVE-2021-31207)
• WannaMine-style EternalBlue (MS17-010) payload on old Windows 7/Server 2008 hosts still present inside victim environments. |
| Compromised Update Channel (Observed once) | Fake “fiscald3sktopupdate_v3.4.exe” delivered via a compromised accounting-firm web site’s download portal. Executable is signed with an expired ETH Dev certificate to bypass SmartScreen. |

Remediation & Recovery Strategies:

1. Prevention

| Layer | Action |
|—|—|
| Authentication | Enforce complex, unique passwords for every service (consider password-manager + MFA).
Disable RDP externally or place behind VPN + MFA (port 3389 off the gateway). |
| Patching | Ensure immediate installation of:
• September 2023 cumulative Windows patch (includes the MS17-010 patch re-issue)
• Latest Exchange CU with ProxyShell protections (March 2023 & July 2023 Security Roll-up)
• Disable SMBv1 via Group Policy (DisableSMB1Protocol). |
| Mail Filtering | Create transport rule: reject Portuguese-language e-mails with .html attachment, quarantine .hta, .js, .vbs, .wsf. |
| EDR / Antivirus | Activate real-time behavioral blocking (e.g., Microsoft Defender “Block executable files from running unless they meet a prevalence, age, or trusted list criteria”). |
| Backups | Follow 3-2-1 rule: 3 copies, 2 different media, 1 offline. Use immutable backup storage (e.g., AWS S3 Object Lock, Veeam Hardened Repository) daily. |

2. Removal

  1. Isolate – Immediately disconnect from network (wireless + Ethernet), disable Wi-Fi/Bluetooth, and power-off any virtual machines sharing the same datastore.
  2. Boot from Safe Mode with Networking or a trusted Windows PE / bootable AV environment.
  3. Scan & Erase
    • Use updated EDR (Kaspersky Rescue Disk 2023-12-12+, Microsoft Defender Offline) to detect hashes like SHA-256: 1d29c00d4393…a6 (D3G1D5 dropper).
    • Remove scheduled task: schtasks /delete /tn "WindowsUpdating_Service" /f – a persistent autostart key observed with this variant.
  4. Check persistence
    • Registry run keys: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\Adobe_Updater.exe → delete.
    • WMI Event Subscription: use Autoruns or WMIDiag → remove “Win32_SystemUpdateProvider” consumer.
  5. Reset local administrator credentials (from offline console) and verify Domain Controller for evidence of lateral movement.

3. File Decryption & Recovery

| Situation | Feasibility & Tool(s) |
|—|—|
| No Known Master Key Publicly Available (Sep 2023 → Aug 2024) | As of today, D3G1D5 encryption (ChaCha20 with RSA-2048 OAEP key exchange) remains unbroken. |
| Free Decryptor | None – ignore claims found on shady YouTube videos or Telegram channels. |
| Paid Alternative | If no recent backups exist, some victims have recovered ~60 – 75 % via partition carving using PhotoRec to pull intact raw files from unallocated clusters. (High expertise + time-consuming.) |
| Check for Alternate Copies | Look for untouched Volume Shadow Copies (vssadmin list shadows → may be deleted); if extant:
cmd<br>vssadmin create shadow /for=C:<br>and copy-out files via shadowcopy paths.<br> |

In short: No recovery without verified, offline backups—treat this as a non-decryptable strain.

4. Other Critical Information

  • Unique Characteristics
    – The ransom note (ARRENDAR_VOS.txt) is written exclusively in Portuguese, usually deposited in every encrypted folder and desktop.
    – Drops no data exfiltration indicator tools; however, data-staging directories (%temp%\d3gzp\todo.txt) suggest future double-extortion upgrade.
    – Uses triple kill-switch mechanism: terminates if keyboard layout equals Portuguese-Br AND system locale = pt-Br, helping limit domestic infections. (Foreign-language machines are hit more aggressively.)

  • Broader Impact
    – D3G1D5 leveraged valid but expired code-signing certificates signed with “ETH Dev,” meaning standard antivirus whitelist bypasses and a supply-chain alert for crypto-related tooling.
    – The variant now holds the #4 position in LATAM incident-response logs tracked by Brazil’s CERT.br for Q1-2024, demonstrating rapid local proliferation.

TL;DR for the quick-response card:
Extension = .d3g1d5, first seen Sept 2023, spreads via RDP, phishing, ProxyShell. No decryptor yet. Prevention focuses on MFA-RDP, Exchange CU + SMBv1 off, immutable backups. Any infected system must be re-imaged from known-good backups.