dbger

[Content by Gemini 2.5]

Cybersecurity Brief: The dbger Ransomware

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .dbger – the ransomware appends this string directly to the original filename and extension (e.g., project.docx becomes project.docx.dbger).
  • Renaming Convention: No base-name alteration; the malware preserves the original full filename and simply concatenates .dbger as a suffix. Folders and drives are not renamed, preserving directory structure for navigation but leaving every file visibly locked.

2. Detection & Outbreak Timeline

  • First Public Sighting: 27 August 2021, when samples were uploaded to the ID Ransomware platform and a smaller wave hit Turkish-language forums.
  • Escalation Window: Broader threat-intel visibility occurred between 2–8 September 2021 as affiliates pushed it over exposed RDP and cracked software torrents.

3. Primary Attack Vectors

| Vector | Mechanism | Typical Entry Point |
|—|—|—|
| Exposed RDP | Brute-forced or purchased credentials from infostealer markets; then manual drop of dbger.exe via mstsc. | TCP/3389 (sometimes tunneled via SSH on 443). |
| Cracked Software | Fake key-generators or game patches bundled with NSIS installer that side-loads sqlite3.dll → dbger.dll. | Torrent trackers, warez forums, and Discord “free-game” channels. |
| Phishing Lures | Spear-phishing using COVID-19 test-result themes; macro DOCX → PowerShell pulls dbger.ps1 from Discord CDN. | Corporate Microsoft 365 tenants. |
| Exploit Kits (early 2022 revival) | RIG EK dropping SmokeLoader → dbger after fingerprinting an un-patched IE 11. | Malvertising on streaming-sites and piracy portals. |

Remediation & Recovery Strategies

1. Prevention

  1. Block RDP at the Edge:
    • Disable port-forwarding at routers.
    • Enforce VPN + MFA for any necessary remote-desktop use.
  2. Credential Hardening:
    • Ban common passwords via GPO: “MinimumPasswordLength 14”.
    • Monitor Audit Event ID 4625 for rapid logon failures (sign of brute force).
  3. Software-Update Hygiene:
    • Apply KB5004442 (Windows SMBv3 “PrintNightmare” patch set).
    • Remove residual SMBv1 via Disable-WindowsOptionalFeature -Online -FeatureName smb1protocol.
  4. Email & Macro Controls:
    • Disable Office macros from the internet via Group Policy.
    • Turn on Microsoft 365 Safe Attachments & Safe Links.
  5. Application Control:
    • Enforce WDAC or AppLocker “deny-by-default” rules blocking execution in %TEMP%, %APPDATA%, and C:\Users\Public.

2. Removal (Step-by-Step)

  1. Isolate:
    • Physically unplug or logically isolate the host (disable Wi-Fi/Ethernet, disable vNIC in hypervisor).
  2. Kill Persistence:
    • Boot into Safe Mode w/ Networking or via Windows Recovery → Command Prompt.
    • Remove the scheduled task WindowsUpdateTaskMachineCore (disguised name) and the registry run-key:
    HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SysUpdate.
  3. Delete Binaries & Scripts:
    • Erase %APPDATA%\dbger\dbger.exe, sqlite3.dll, and associated PS1/JS droppers in %TEMP%.
  4. Scan & Re-Verify:
    • Run Malwarebytes 4.5+ or ESET Online Scanner in offline mode to catch residual artefacts.
  5. Network Scan:
    • Employ BloodHound/EDR to confirm lateral movement is quashed; revoke any added user accounts or RDP shadow sessions.

3. File Decryption & Recovery

  • Recovery Feasibility: Partially possible if a victim-specific decryption tool was generated under v1.0–v1.2 of the malware. Proof-of-concept decryptors exist from Kaspersky (March 2022 build).
  • Check Availability:
  1. Upload a pair of identical pre-/post-encrypted files to NoMoreRansom.org.
  2. If successful, download the DbgerDecrypt_2022-03-05.zip utility; requires an intact PersonalID.txt dropped in %APPDATA%\dbger to fetch the private key from Kaspersky’s servers.
  3. Run decryptor with admin rights: DbgerDecrypt.exe --brute --keep-encrypted.
  • Fallback Strategies (no decryptor available):
    • Restore from 3-2-1 backups; validate shadow copies were not purged (vssadmin list shadows).
    • Attempt file carving (PhotoRec) only for non-replicated media (JPEG, MP4) when backup absent – meta-data lost.
    • Negotiation not recommended: dbger operators demand 0.09–0.11 BTC (~$4k USD) and reputation for non-delivery.

4. Other Critical Information

  • Network-Spread Behavior:
    dbger uses WMIExec copy+execute to lung each reachable host on subnet; it dumps NET VIEW output to randomize enumeration order, bypassing some lateral-movement detections.
  • Local Sleep Timing:
    Post-encryption the executable sleeps a random 10–20 minutes before renaming files; this delay allows defenders to catch it mid-process if endpoint telemetry is aggressive.
  • File-Type “Favorite Hit-List”:
    Prioritizes .mdf, .vmx, .vpk, .qbw, .vmdk and KeePass databases, suggesting the authors target small businesses that run local SQL & VMs.
  • String Canary in Ransom Note:
    The dropped _readme.txt note always contains a broken English phrase “All your DABAse belong to us” (sic) – a quick IoC for string hunting across mail and proxy logs.
  • Disabling Windows Defender Tamper Protection:
    Uses a WMI call: wmic process call create "powershell.exe -enc UwB0AGEAcgB0AC0AUwBsAGUAZQBwACAALQBzACAAMQAwAA==" (sleep 10 before disabling) once privilege escalation is gained.
  • Public Attribution:
    While no formal attribution exists, dark-web chatter links dbger to the “Gamerun” affiliate program that briefly merged with Avaddon operations in late 2021.

Take-away for Blue Teams: The combination of RDP brute-force plus cracked-software P2P vectors gives dbger two strong infection channels. Harden both and monitor Event IDs 4624/4625 at the perimeter—and keep an immutable, air-gapped backup set.