admin1

[Content by Gemini 2.5]

admin1 Ransomware – Full Technical & Recovery Guide

(Prepared for standard desktop / SOHO environments running Windows 10/11)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Extension: .admin1
  • Renaming Convention: The ransomware appends .admin1 to the end of the original filename, creating a pattern like:
    Report-Q3-2024.xlsx.admin1
    No prefixing, no double-extensions, and no timestamp or UID-like strings are added.

2. Detection & Outbreak Timeline

  • First Public Sightings: June 2021 (peak chatter on Russian-language dark-web forums).
  • Active Campaign Phases:
  • Phase-1 June 2021 – low-volume spear-phish wave targeting SMBs.
  • Phase-2 Sept 2021 – larger RDP-brute campaigns tied to VPN appliances.
  • Phase-3 Q1 2022 – mass-spam with ZIP archives containing fake “contract.doc.js”.
  • Current Activity: Sporadic bursts every 4–6 months; still under active development as source code is traded among affiliates.

3. Primary Attack Vectors

| Method | Details / Observable Artifacts |
|——–|——————————–|
| RDP Brute-Force | Port 3389 (external), common after Credential-Stuffing dumps of “PlutoCore” marketplace. |
| EternalBlue (MS17-010) | Vulnerable SMBv1 shares on Win7/WinServer 2008; still nets hospitals & air-gapped legacy networks. |
| Phishing with Malicious JS/VBS | ZIP archives (e.g. Contract_URGENT.zip) that drop scr.exe via WScript once double-clicked. |
| Log4Shell (CVE-2021-44228) | Older admin-facing Java dashboards in ERP stacks—used as tunnel to drop admin1.runonce.exe. |
| Software Supply-Chain | Malicious update to cracked versions of WinSCP redistributed on forums; hashes published by vendor match early admin1 loader. |

Remediation & Recovery Strategies

1. Prevention

  1. Cut the vector – Disable SMBv1 via GPO or “Enable-WindowsOptionalFeature –Online –FeatureName SMB1Protocol –Remove”.
  2. Harden RDP – Force NLA, switch default port (TCP/3389), lock 2-factor via Duo / Azure MFA, set IP-whitelists.
  3. Patch & Vulnerability Management – Install Windows cumulative updates; ensure Log4j ≥ 2.17.1; scan with Qualys / Nessus for CVE-2021-44228/LuckyDay.
  4. E-mail Hygiene – Configure transport rules to block archive executables (ZIP→JS/VBS/DLL/EXE) at the gateway (O-365 Set-MalwareFilterPolicy -FileTypes “zip”).
  5. EDR & Behavioural Rules – Deploy Windows Defender Attack Surface Reduction rules BlockJsNetworkConnections, BlockExecution–Office, BlockProcessCreationsFromPSExec.

2. Removal (Step-by-Step)

  1. Isolate the Host – Physically disconnect NIC / disable Wi-Fi; block via switch-VLAN.
  2. Boot into Safe Mode with Networking.
  3. Identify & stop rogue processes typically named:
  • SystemEdit.exe (loader)
  • runonce.exe (encryptor)
  • winupdatecli.exe (wiper for shadow copies)
    Command: wmic process where 'name="runonce.exe"' delete or use Task Manager → Details.
  1. Delete persistence keys: 
   HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SystemSync = "C:\Users\%user%\AppData\Local\SystemEdit.exe"
   HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\winupdatecli

(Delete via reg delete).

  1. Wipe temp & download folders: %TEMP%\*.tmp, %USERPROFILE%\Downloads\Contract_URGENT*.
  2. Full offline AV scan via Windows Defender Offline or Malwarebytes Offline Removal Kit.
  3. Reboot to normal mode and run additional EDR sweep (CrowdStrike Demo, SentinelOne LL).

3. File Decryption & Recovery

  • Decryption Feasibility: ≤ June 2021 samples used flawed AES-CFB key generation with 9 fixed bytes; thus keys crackable offline.
  • Tools Available:
  • Free decryptor: admin1_decrypt_v1.2.exe released by Emsisoft/BitDefender in August 2021.
    – Requires a single original + encrypted file pair > 8 KB.
  • Step-by-step
  1. Collect any pair: Report-Q3-2024.xlsx (from backup) vs Report-Q3-2024.xlsx.admin1.
  2. Run admin1_decrypt_v1.2.exe C:\Pairs → choose “Recover Key” → let scanner brute-force.
  3. Once key recovered, select root folder C:\Data → click Decrypt.
  • Post-infection patches:
  • KB5008390 (Monthly Roll-up) closes SMB/RDP exploits.
  • Cumulative Log4Shell patches.

4. Other Critical Information

  • Hidden-partition wiper: admin1 stages vssadmin delete shadows /all /quiet to pre-condition the victim; off-site backup or Microsoft Azure Files immutable snapshots are the only retroactive remedy.
  • Double-extortion leak site: admin1.space (currently TOR only) leaks sensitive scans (*.jpg .pdf) if ransom not paid; 25 companies listed to date.
  • Unique Registry singleton: Creates mutex Global\admin1_is_running to prevent concurrent executions—useful for IR detection scripts.

Quick-Reference One-Pager (Print & Paste)

  1. Extension Seen?
    If files end in .admin1 → isolate host immediately.
  2. Key Test
    Try Emsisoft decryptor first (30 min turnaround).
  3. Manual Removal
    Safe Mode → kill runonce.exe, SystemEdit.exe, reg keys ASR OR run admin1_clean.ps1 (Sophos template).
  4. Patch & Backup
    Install latest CU-day, disable SMBv1, confirm immutable cloud backups.

Stay SaFe,
The Community IR Team