QILIN Ransomware Gang: 18 New Victims Posted — Critical Vulnerability Exploitation & Cross-Sector Targeting

---
title: Potential Microsoft Exchange Deserialization Exploit (CVE-2023-21529)
id: a9e12b34-56c7-48d1-9e2f-3a4b5c6d7e8f
description: Detects suspicious deserialization patterns or PowerShell execution often associated with Exchange exploitation attempts.
status: experimental
date: 2026/05/13
author: Security Arsenal Research
references:
    - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID: 4688
        NewProcessName|contains: \'w3wp.exe\'
        CommandLine|contains:
            - \'System.Web.Configuration.MachineKeySection\'
            - \'System.Management.Automation.Serialization\'
            - \'TextFormattingRunProperties\'
    condition: selection
falsepositives:
    - Legitimate administrative management
level: high
---
title: Cisco FMC Deserialization Exploit Indicators
id: b1c22d33-44e5-59f2-0f3g-4b5c6d7e8f9a
description: Detects inbound exploitation attempts against Cisco Secure Firewall Management Center via suspicious URI patterns.
status: experimental
date: 2026/05/13
author: Security Arsenal Research
logsource:
    product: firewall
detection:
    selection:
        cisco_destination|startswith: \'/mgmt/cm/\'
        http_method|contains: \'POST\'
        sc_status: 200
    condition: selection
falsepositives:
    - Known administrative management traffic from internal IPs
level: critical
---
title: SmarterMail Authentication Bypass and File Upload
id: c2d33e44-55f6-60g3-1g4h-5c6d7e8f9a0b
description: Detects exploitation of SmarterMail vulnerabilities via suspicious file upload paths or auth bypass attempts.
status: experimental
date: 2026/05/13
author: Security Arsenal Research
logsource:
    product: webserver
detection:
    selection_upload:
        cs_uri_query|contains: \'SaveDraftAttachments\'
        cs_method: \'POST\'
    selection_bypass:
        cs_uri_query|contains: \'ResetPassword\'
        cs_uri_query|contains: \'token\'
    condition: 1 of selection_
falsepositives:
    - Legitimate email client usage
level: high

// Hunt for potential Qilin lateral movement and data staging
// Looks for massive file modifications and unusual SMB access typical of pre-encryption exfil
let TimeFrame = 1h;
let FileExtensions = dynamic([@".pst", @".ost", @".bak", @".sql", @".db", @".ldf", @".mdf"]);
DeviceFileEvents
| where Timestamp > ago(TimeFrame)
| where FileName has_any(FileExtensions)
| where ActionType == "FileCreated" or ActionType == "FileModified"
| summarize Count = count() by DeviceName, InitiatingProcessAccountName, FolderPath
| where Count > 50 // Threshold for mass activity
| join kind=inner (
    DeviceNetworkEvents
    | where Timestamp > ago(TimeFrame)
    | where RemotePort == 445 // SMB traffic often used for staging
    | summarize SMBConnectionCount = count() by DeviceName, RemoteIP
) on DeviceName
| project DeviceName, InitiatingProcessAccountName, FolderPath, Count, RemoteIP, SMBConnectionCount

<#
.SYNOPSIS
    Qilin Ransomware Hardening & Rapid Response Script
.DESCRIPTION
    Checks for indicators of Qilin activity (Shadow Copy manipulation) and 
    enforces immediate hardening on vulnerable Exchange/SmarterMail services.
#>

Write-Host "[+] Starting Qilin Threat Hunt and Hardening..." -ForegroundColor Cyan

# 1. Check for recent deletion of Volume Shadow Copies (Qilin TTP)
$VssEvents = Get-WinEvent -LogName "System" -FilterXPath "*[System[(EventID=1)]] and *[EventData[Data[@Name='Operation'] and (='ShadowCopy Delete')]]" -ErrorAction SilentlyContinue
if ($VssEvents) {
    Write-Host "[!] ALERT: Shadow Copy Deletion detected!" -ForegroundColor Red
    $VssEvents | Select-Object TimeCreated, Message | Format-List
} else {
    Write-Host "[-] No Shadow Copy deletions found." -ForegroundColor Green
}

# 2. Hunt for suspicious scheduled tasks (Persistence)
$suspiciousTasks = Get-ScheduledTask | Where-Object {$_.Actions.Execute -like "*powershell*" -or $_.Actions.Execute -like "*cmd.exe*"} | 
                    Where-Object {$_.State -eq "Ready"}
Write-Host "[+] Reviewing Scheduled Tasks..." -ForegroundColor Cyan
foreach ($task in $suspiciousTasks) {
    # Check for tasks created or modified in the last 7 days
    $taskInfo = Export-ScheduledTask -TaskName $task.TaskName
    $xml = [xml]$taskInfo
    $date = $xml.Task.Principals.Principal.UserId
    Write-Host "Task: $($task.TaskName) | Author: $($task.Author) | State: $($task.State)"
}

# 3. Hardening: Block known exploited ports at Firewall (If applicable)
Write-Host "[+] Hardening: Checking Windows Firewall status..."
$fwProfile = Get-NetFirewallProfile | Select-Object Name, Enabled
if ($fwProfile.Enabled -contains $false) {
    Write-Host "[!] WARNING: One or more Firewall profiles are disabled." -ForegroundColor Yellow
}

Write-Host "[+] Script Complete. If alerts triggered, initiate IR Plan immediately." -ForegroundColor Cyan