---
title: Potential ConnectWise ScreenConnect Authentication Bypass
id: 4234c7d2-5a5a-4e8a-9e1e-1b2c3d4e5f6a
description: Detects suspicious authentication patterns and webshell access associated with CVE-2024-1708 on ConnectWise ScreenConnect servers.
status: experimental
date: 2026/05/16
author: Security Arsenal
references:
    - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
logsource:
    category: web
definition: 'Required fields: cs_uri_query, cs_method, sc_status'
detection:
    selection:
        cs_uri_query|contains:
            - 'Handler.ashx'
            - 'SetupWizard.aspx'
        cs_method: 'POST'
    filter:
        sc_status: 200
    condition: selection and filter
falsepositives:
    - Legitimate administrative configuration changes
level: critical

tags:
    - cve.2024.1708
    - attack.initial_access
    - attack.web_shell

---
title: Cisco FMC Arbitrary Command Execution
id: 8f9e1d2c-3b4a-4f5e-8a7b-9c0d1e2f3a4b
description: Detects potential exploitation of CVE-2026-20131 in Cisco Secure Firewall Management Center via deserialization anomalies or unexpected shell processes.
status: experimental
date: 2026/05/16
author: Security Arsenal
references:
    - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
logsource:
    category: process_creation
    product: windows
definition: 'Required fields: ParentCommandLine, CommandLine'
detection:
    selection:
        ParentImage|endswith: '\\java.exe'
        Image|endswith:
            - '\\cmd.exe'
            - '\\powershell.exe'
            - '\\\bash.exe'
        CommandLine|contains:
            - '/bin/sh'
            - 'whoami'
    condition: selection
falsepositives:
    - Administrative troubleshooting (rare on FMC appliances)
level: critical

tags:
    - cve.2026.20131
    - attack.execution
    - cve.2026.20131

---
title: Suspicious Ransomware Pattern - Qilin GoLang
id: a1b2c3d4-e5f6-4a5b-8c9d-0e1f2a3b4c5d
description: Detects file encryption behavior consistent with Qilin ransomware (GoLang binary) utilizing specific flags or rapid file modification rates.
status: experimental
date: 2026/05/16
author: Security Arsenal
logsource:
    category: file_event
    product: windows
definition: 'Required fields: TargetFilename, Image'
detection:
    selection:
        Image|contains:
            - ':\\Windows\\Temp\\'
            - ':\\Users\\Public\\'
        TargetFilename|endswith:
            - '.qilin'
            - '.encrypted'
    condition: selection | count(TargetFilename) by Image > 50
level: critical

tags:
    - attack.impact
    - ransomware

let timeframe = 1d;
DeviceProcessEvents 
| where Timestamp >= ago(timeframe)
// Look for PsExec and WMI lateral movement tools
| where ProcessName has_any ("psexec.exe", "psexec64.exe", "wmic.exe", "powershell.exe")
// Filter for suspicious command line arguments
| where ProcessCommandLine has_any ("accepteula", "-i", "\\\\\\\\", "Invoke-Command", "New-Object", "DownloadString")
// Exclude known admins if necessary, but in incident response, assume compromise
| project Timestamp, DeviceName, AccountName, ProcessName, ProcessCommandLine, InitiatingProcessFileName
| order by Timestamp desc

<#
.SYNOPSIS
    Detects recent deletion of Volume Shadow Copies (VSS).
    Qilin affiliates often run 'vssadmin delete shadows /all /quiet' prior to encryption.
#>

$EventID = 122 # VSS Admin Delete Event
$TimeSpan = (Get-Date).AddHours(-24)

$VssEvents = Get-WinEvent -FilterHashtable @{LogName='Application'; ProviderName='VSS'; ID=$EventID; StartTime=$TimeSpan} -ErrorAction SilentlyContinue

if ($VssEvents) {
    Write-Host "[CRITICAL] Volume Shadow Copy Deletion Detected!" -ForegroundColor Red
    $VssEvents | Select-Object TimeCreated, Message | Format-List
} else {
    Write-Host "[INFO] No VSS deletion events found in the last 24 hours." -ForegroundColor Green
}

# Check for suspicious scheduled tasks created recently (common persistence)
$suspiciousTasks = Get-ScheduledTask | Where-Object {$_.Date -ge (Get-Date).AddDays(-1)}
if ($suspiciousTasks) {
    Write-Host "[WARNING] Recently Scheduled Tasks found:" -ForegroundColor Yellow
    $suspiciousTasks | Select-Object TaskName, Date, Author
}


---

# Incident Response Priorities

**T-Minus Detection Checklist (Pre-Encryption):**
1.  **Check for Web Shells:** Audit IIS/Java logs for the ScreenConnect `Handler.ashx` exploit string.
2.  **Audit Firewall Configs:** If using Cisco FMC, review configuration change logs for unauthorized alterations (CVE-2026-20131).
3.  **MFA Fatigue:** Check Azure AD/MFA logs for rapid denial/failure patterns from unusual geo-locations (e.g., Argentina, Thailand).
n
**Critical Asset Exfil Targets:**
*   **Healthcare:** PACS archives (imaging), Electronic Health Records (EHR) databases (SQL/Oracle).
*   **Manufacturing:** CAD files (.dwg, .stp), ERP systems (SAP), MRP databases.
*   **Logistics:** Customer manifests, shipping route data, customs documentation.

**Containment Actions (Ordered by Urgency):**
1.  **Isolate Internet-Facing Assets:** Immediately disconnect ConnectWise ScreenConnect servers and SmarterMail gateways from the network.
2.  **Segment VPNs:** Revoke all VPN session tokens and force MFA re-registration for all users.
3.  **Disable SMB:** Block inbound SMB (TCP 445, 139) at the host firewall level on non-domain controllers to halt PsExec spread.

---

# Hardening Recommendations

**Immediate (24 Hours):**
*   **Patch Critical CVEs:** Apply the patch for **CVE-2024-1708 (ConnectWise)** immediately. If patching is not possible, enforce strict MFA on the ScreenConnect web interface.
*   **SmarterMail Hardening:** If running SmarterMail, upgrade to the latest build to address CVE-2026-23760. Review mail logs for unauthorized `Login.aspx` access.
*   **Cisco FMC Review:** Check for unauthorized software updates or configuration changes; upgrade FMC software to the patched version for CVE-2026-20131.

**Short-Term (2 Weeks):**
*   **Network Segmentation:** Move medical devices (IoMT) and manufacturing OT systems to isolated VLANs. Ensure they cannot initiate outbound connections to the internet.
*   **Zero Trust Architecture:** Implement "Never Trust, Always Verify" for all remote management tools. Transition to Just-in-Time (JIT) access for administrative credentials.

---