The threat landscape in 2026 continues to be defined by the weaponization of edge devices. Security Arsenal is tracking a concerning surge in activity attributed to the INC ransomware group, which has recently shifted focus to SonicWall Secure Mobile Access (SMA) 1000 series appliances. According to intelligence disclosed by Resecurity, this threat actor is not only exploiting unpatched vulnerabilities in these devices but is also employing aggressive "double-extortion" tactics, including direct phone calls to victims to pressure them into payment.
This post provides a technical breakdown of the attack surface, detection strategies for the exploitation phase, and immediate remediation steps to secure your perimeter.
Technical Analysis
Affected Products
- Vendor: SonicWall
- Product: Secure Mobile Access (SMA) 1000 series appliances
Vulnerability & Exploitation Status
- CVE: The specific CVE identifier for the flaw being exploited in this specific campaign has not been publicly disclosed in the source material, but it is described as a critical unpatched vulnerability.
- CVSS Score: Estimated High/Critical (based on active exploitation and RCE capabilities).
- Exploitation Status: CONFIRMED ACTIVE EXPLOITATION. Threat actors are leveraging this flaw to gain initial access to global organizations.
Attack Chain
- Initial Access: The threat actor scans for internet-facing SonicWall SMA 1000 appliances. They exploit the security issue to gain unauthorized access to the device.
- Persistence & Movement: Once the appliance is compromised, actors use it as a pivot point to move laterally into the internal network, often utilizing valid credentials stolen from the device or by tunneling traffic.
- Execution: Ransomware payloads are deployed on internal critical systems (file servers, domain controllers).
- Extortion: Following encryption and data exfiltration, the INC group initiates a harassment campaign. This includes emails and direct phone calls to executives and IT staff, applying psychological pressure to expedite ransom payments.
Detection & Response
Detecting this threat requires monitoring both the edge device (if logs are forwarded) and the internal network for anomalous behaviors stemming from the compromised appliance.
Sigma Rules
The following rules detect potential web shell activity on the SMA interface and ransomware execution patterns on Windows endpoints.
---
title: Potential Web Shell Activity on SonicWall SMA
id: a1b2c3d4-2026-4e5a-8b9c-0d1e2f3a4b5c
status: experimental
description: Detects potential command execution or web shell activity on SonicWall SMA appliances based on URI patterns and user agents.
references:
- https://securityaffairs.com/196607/malware/inc-ransomware-is-calling-victims-pressure-tactics-post-sonicwall-zero-day-exploit.html
author: Security Arsenal
date: 2026/04/06
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
product: sonicwall
detection:
selection:
c-uri|contains:
- '/api/'
- '/cgi-bin/'
c-uri|contains:
- 'cmd.exe'
- 'powershell'
- 'cat%20'
- 'whoami'
condition: selection
falsepositives:
- Administrative testing via API
level: high
---
title: INC Ransomware File Encryption Pattern
id: e5f6g7h8-2026-4i5j-6k7l-8m9n0o1p2q3r
status: experimental
description: Detects mass file creation with the .inc extension often associated with INC ransomware encryption.
references:
- Internal Threat Intel
author: Security Arsenal
date: 2026/04/06
tags:
- attack.impact
- attack.t1486
logsource:
category: file_create
product: windows
detection:
selection:
TargetFilename|endswith: '.inc'
Image|endswith:
- '\unknown.exe'
- '\cmd.exe'
- '\powershell.exe'
condition: selection | count(TargetFilename) by Image > 10
falsepositives:
- Rare legitimate application using .inc extension
level: critical
KQL (Microsoft Sentinel)
Hunt for unusual administrative access to the SonicWall SMA and lateral movement from the appliance IP address.
// Hunt for SonicWall SMA Admin Login Anomalies
Syslog
| where DeviceVendor == "SonicWall"
| where Facility == "auth"
| where SyslogMessage has "SMA" and (SyslogMessage has "login" or SyslogMessage has "admin")
| project TimeGenerated, SourceIP, DeviceName, SyslogMessage
| summarize count() by SourceIP, bin(TimeGenerated, 5m)
| where count_ > 5 // Threshold for brute force or rapid logins
;
// Hunt for Lateral Movement from known SMA IP ranges (Replace 'SMA_IP_Range')
let SMA_IP_Range = "192.168.1.0/24"; // Update to your appliance IP
DeviceNetworkEvents
| where InitiatingIP has_any (SMA_IP_Range)
| where ActionType in ("ConnectionAllowed", "ConnectionSuccess")
| project TimeGenerated, InitiatingIP, DestinationIP, DestinationPort, RemotePort
| where DestinationPort in (445, 139, 3389, 22, 5985)
Velociraptor VQL
This artifact hunts for the presence of INC ransomware notes or suspicious processes on Windows endpoints.
-- Hunt for INC Ransomware Artifacts
SELECT
OSPath,
Mtime,
Size,
Mode
FROM glob(globs="C:\\*\\*.inc")
WHERE
Size < 1024 AND Mtime > now() - 7d
UNION ALL
SELECT
Pid,
Name,
CommandLine,
Exe,
Username
FROM pslist()
WHERE
Name =~ "cmd.exe" AND CommandLine =~ "\\.inc"
OR Name =~ "powershell.exe" AND CommandLine =~ "encryp"
Remediation Script (PowerShell)
Use this script on Windows endpoints to scan for indicators of compromise (IOCs) related to INC ransomware.
# INC Ransomware IOC Scanner
# Runs as a primitive triage script on endpoints
$ErrorActionPreference = "SilentlyContinue"
$Drives = Get-PSDrive -PSProvider FileSystem | Select-Object -ExpandProperty Root
$Extensions = @("*.inc")
$RansomNotes = @("README_INC.txt", "INC_RESTORE.txt")
Write-Host "[+] Scanning for INC Ransomware Artifacts..." -ForegroundColor Cyan
# Scan for encrypted extensions
foreach ($Drive in $Drives) {
foreach ($Ext in $Extensions) {
$Files = Get-ChildItem -Path $Drive -Filter $Ext -Recurse -ErrorAction SilentlyContinue | Select-Object FullName, CreationTime
if ($Files) {
Write-Host "[!] Found Encrypted Files:" -ForegroundColor Red
$Files | ForEach-Object { Write-Host $_.FullName }
}
}
}
# Scan for ransom notes
foreach ($Note in $RansomNotes) {
$Notes = Get-ChildItem -Path $Drive -Filter $Note -Recurse -ErrorAction SilentlyContinue
if ($Notes) {
Write-Host "[!] Found Ransom Notes:" -ForegroundColor Red
$Notes | ForEach-Object { Write-Host $_.FullName }
}
}
Write-Host "[-] Scan Complete." -ForegroundColor Green
Remediation
Immediate action is required to mitigate the risk of the INC ransomware exploiting SonicWall SMA flaws.
-
Patch Management:
- Review the SonicWall Security Advisory for the SMA 1000 series immediately.
- Action: Upgrade to the latest patched firmware release provided by SonicWall that addresses the "unpatched vulnerability" mentioned in current intelligence.
-
Network Segmentation & Access Control:
- Immediate Action: If immediate patching is not possible, disallow internet access to the SonicWall SMA management interface (HTTPS/HTTP). Enforce VPN-based access strictly for administrators.
- Place SMA appliances in a dedicated DMZ with strict egress rules to limit lateral movement capabilities if compromised.
-
Compromise Assessment:
- Assume active compromise if the appliance is unpatched and internet-facing. Review logs for unusual administrative logins, mass configuration changes, or unknown file transfers.
- Rotate all credentials (admin, domain, VPN) associated with the SMA appliance.
-
Incident Response Planning:
- Brief executive leadership and call center staff on the extortion tactics. If the organization is breached, the threat actor may call directly. Establish a protocol: "Do not engage, transfer to the Security Incident Response Team."
Related Resources
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