StormEncryptor Ransomware: Detection and Response Guide for the Former Medusa Affiliate Campaign

---
title: Shadow Copy Deletion and Recovery Tampering via LOLBins
id: 8f2b6c14-3d91-4e75-a902-7c4d5e6f8a1b
status: experimental
description: Detects vssadmin, wmic, and bcdedit abuse consistent with ransomware pre-encryption behavior observed in Medusa-affiliate tradecraft now associated with StormEncryptor deployment.
references:
  - https://attack.mitre.org/techniques/T1490/
  - https://www.bleepingcomputer.com/news/security/new-stormencryptor-ransomware-used-by-former-medusa-affiliate/
author: Security Arsenal
date: 2026/01/15
tags:
  - attack.impact
  - attack.t1490
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    Image|endswith:
      - '\vssadmin.exe'
      - '\wmic.exe'
      - '\bcdedit.exe'
      - '\wbadmin.exe'
      - '\diskshadow.exe'
  selection_cmd:
    CommandLine|contains:
      - 'delete shadows'
      - 'shadowcopy delete'
      - 'delete catalog'
      - 'recoveryenabled no'
      - 'ignoreallfailures'
      - '/raw {*}'
  condition: selection_img and selection_cmd
falsepositives:
  - Rare. Legitimate backup administrators use wbadmin and vssadmin, but combined with deletion verbs this is near-certainly malicious in most environments.
level: critical
---
title: PsExec-Style Remote Service Execution for Mass Deployment
id: 3c9a7e52-1b48-4d63-9f14-2e8b5c7d9a3f
status: experimental
description: Detects remote service installation patterns consistent with ransomware affiliates staging encryptors across hosts via psexec-like tooling, a documented Medusa affiliate lateral movement method.
references:
  - https://attack.mitre.org/techniques/T1569/002/
  - https://www.bleepingcomputer.com/news/security/new-stormencryptor-ransomware-used-by-former-medusa-affiliate/
author: Security Arsenal
date: 2026/01/15
tags:
  - attack.lateral_movement
  - attack.t1021.002
  - attack.t1569.002
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith:
      - '\psexec.exe'
      - '\psexesvc.exe'
      - '\paexec.exe'
      - '\csexec.exe'
      - '\remcom.exe'
  filter_known_admin:
    ParentImage|endswith:
      - '\svchost.exe'
  condition: selection and not filter_known_admin
falsepositives:
  - Legitimate systems administration (SCCM, PDQ Deploy). Baseline your admin tooling service names and tune accordingly.
level: high
---
title: Cloud Sync Exfiltration Tool Execution
id: 61d4f8a9-7c25-4b83-ae06-9f3d2c5e8b47
status: experimental
description: Detects execution of Rclone and similar cloud-sync utilities frequently abused by ransomware affiliates for data exfiltration prior to encryption, consistent with double-extortion tradecraft.
references:
  - https://attack.mitre.org/techniques/T1567/002/
  - https://www.bleepingcomputer.com/news/security/new-stormencryptor-ransomware-used-by-former-medusa-affiliate/
author: Security Arsenal
date: 2026/01/15
tags:
  - attack.exfiltration
  - attack.t1567.002
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    Image|endswith:
      - '\rclone.exe'
      - '\megacmd.exe'
      - '\filezilla.exe'
      - '\winscp.exe'
  selection_cmd:
    CommandLine|contains:
      - 'copy'
      - 'sync'
      - 'move'
      - 'put'
  filter_path:
    Image|startswith:
      - 'C:\Program Files\'
      - 'C:\Program Files (x86)\'
  condition: selection_img and selection_cmd and not filter_path
falsepositives:
  - Legitimate Rclone backup jobs — these typically run from installed paths or known service accounts; executions from temp/user-profile paths are highly suspicious.
level: high

// Hunt: Pre-encryption ransomware behaviors across the estate (last 7 days)
// Surfaces shadow copy tampering, recovery tampering, mass service execution,
// and exfiltration tooling consistent with Medusa-affiliate / StormEncryptor tradecraft.
let lookback = 7d;
let SuspiciousCmd = dynamic([
    "delete shadows", "shadowcopy delete", "delete catalog",
    "recoveryenabled no", "ignoreallfailures", "bcdedit"
]);
union isfuzzy=true
(DeviceProcessEvents
| where Timestamp >= ago(lookback)
| where FileName in~ ("vssadmin.exe","wmic.exe","bcdedit.exe","wbadmin.exe","diskshadow.exe")
| where ProcessCommandLine has_any (SuspiciousCmd)
| project Timestamp, DeviceName, FileName, ProcessCommandLine, AccountName, InitiatingProcessFileName, ReportId
),
(DeviceProcessEvents
| where Timestamp >= ago(lookback)
| where FileName has_any ("rclone","megacmd","winscp","filezilla")
   or ProcessCommandLine has_any ("rclone ", "megacmd")
| where FolderPath !has "Program Files"
| project Timestamp, DeviceName, FileName, ProcessCommandLine, AccountName, FolderPath, ReportId
),
(DeviceProcessEvents
| where Timestamp >= ago(lookback)
| where FileName in~ ("psexec.exe","psexesvc.exe","paexec.exe","remcom.exe")
| summarize ExecCount = count(), DistinctHosts = dcount(DeviceName),
    FirstSeen = min(Timestamp), LastSeen = max(Timestamp)
    by InitiatingProcessFileName, AccountName
| where DistinctHosts > 3   // fan-out pattern: one source pushing to many hosts
)
| sort by Timestamp desc

-- Artifact: Ransomware pre-impact hunt (StormEncryptor / Medusa-affiliate TTPs)
-- Surfaces shadow-copy tampering processes, exfiltration tooling in user-writable
-- paths, and recently dropped executable payloads in staging directories.
SELECT Pid, Name, CommandLine, Exe, Username, CreateTime
FROM pslist()
WHERE CommandLine =~ '(?i)(delete shadows|shadowcopy delete|recoveryenabled|delete catalog|ignoreallfailures)'
   OR (Name =~ '(?i)(rclone|megacmd|winscp|filezilla)'
       AND Exe =~ '(?i)(\\users\\|\\temp\\|\\programdata\\|\\appdata\\)')
   OR Exe =~ '(?i)\\programdata\\[^\\]+\.exe$'
ORDER BY CreateTime DESC

# StormEncryptor / affiliate-ransomware hardening and verification script
# Run elevated on servers and critical workstations. Validates backup/recovery
# posture, RDP exposure, and tamper protections BEFORE an intrusion succeeds.

# 1. Verify Volume Shadow Copies exist and VSS service is healthy
Write-Host "[*] Checking shadow copy posture..." -ForegroundColor Cyan
$shadows = Get-CimInstance Win32_ShadowCopy -ErrorAction SilentlyContinue
if (-not $shadows) {
    Write-Warning "No shadow copies found. Verify backup strategy — do not rely on VSS alone."
} else {
    Write-Host "[+] $($shadows.Count) shadow copies present (latest: $($shadows[0].InstallDate))"
}
Get-Service VSS | Select-Object Name, Status, StartType

# 2. Audit RDP exposure — a primary Medusa-affiliate initial access vector
Write-Host "[*] Auditing RDP configuration..." -ForegroundColor Cyan
$rdpEnabled = (Get-ItemProperty 'HKLM:\System\CurrentControlSet\Control\Terminal Server').fDenyTSConnections
$nla = (Get-ItemProperty 'HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -Name UserAuthentication -ErrorAction SilentlyContinue).UserAuthentication
Write-Host "    RDP enabled: $(if($rdpEnabled -eq 0){'YES - restrict or disable'}else{'No'})"
Write-Host "    NLA enforced: $(if($nla -eq 1){'Yes'}else{'NO - enable immediately'})"
if ($rdpEnabled -eq 0 -and $nla -ne 1) {
    Set-ItemProperty 'HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -Name UserAuthentication -Value 1
    Write-Host "[+] NLA enforced." -ForegroundColor Green
}

# 3. Enable Controlled Folder Access (ransomware canary protection)
Write-Host "[*] Enabling Controlled Folder Access..." -ForegroundColor Cyan
Set-MpPreference -EnableControlledFolderAccess Enabled
Write-Host "[+] CFA enabled. Audit with: Get-MpPreference | Select EnableControlledFolderAccess"

# 4. Confirm tamper protection is on (blocks attacker disablement of Defender)
$tp = Get-MpComputerStatus | Select-Object -ExpandProperty IsTamperProtected
Write-Host "[*] Defender Tamper Protection: $tp" -ForegroundColor $(if($tp){'Green'}else{'Red'})

# 5. Restrict vssadmin/bcdedit abuse via WDAC/AppLocker is ideal; at minimum,
#    alert on their use. Verify recent suspicious usage in event log:
Write-Host "[*] Recent vssadmin/bcdedit executions (4688 audit required):" -ForegroundColor Cyan
Get-WinEvent -FilterHashtable @{LogName='Security'; Id=4688} -MaxEvents 5000 -ErrorAction SilentlyContinue |
  Where-Object { $_.Message -match 'vssadmin|bcdedit|wbadmin|diskshadow' } |
  Select-Object TimeCreated, Message -First 20

# 6. Verify offline/immutable backup reachability (the real ransomware control)
Write-Host "[*] Reminder: confirm immutable/off-airgap backup tested within last 30 days." -ForegroundColor Yellow