CVE-2026-20245: Cisco Catalyst SD-WAN Manager Exploitation — Detection and Remediation Guide

---
title: Cisco SD-WAN Manager Web Shell Activity
id: 9a8f7c6d-5e4b-3a2c-1d9e-0f8a7b6c5d4e
status: experimental
description: Detects the web server process (typically Java/Tomcat or Nginx) spawning a shell on Cisco Catalyst SD-WAN Manager, indicative of web shell or RCE activity related to CVE-2026-20245.
references:
  - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
author: Security Arsenal
date: 2026/06/03
tags:
  - attack.initial_access
  - attack.web_shell
  - attack.t1505.003
logsource:
  category: process_creation
  product: linux
detection:
  selection:
    ParentImage|endswith:
      - '/java'
      - '/nginx'
    Image|endswith:
      - '/sh'
      - '/bash'
      - '/dash'
  condition: selection
falsepositives:
  - Legitimate administrative troubleshooting via console (rare for web parent)
level: critical
---
title: Suspicious Outbound Connection from SD-WAN Manager
id: 1b2c3d4e-5f6a-7b8c-9d0e-1f2a3b4c5d6e
status: experimental
description: Detects outbound network connections from the management plane to non-standard ports or external IPs, which may indicate C2 beaconing or data exfiltration following exploitation.
references:
  - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
author: Security Arsenal
date: 2026/06/03
tags:
  - attack.command_and_control
  - attack.t1071
logsource:
  category: network_connection
  product: linux
detection:
  selection:
    Image|contains:
      - 'java'
      - 'nginx'
    DestinationPort|notin:
      - 443
      - 80
      - 8443
      - 8080
  condition: selection
falsepositives:
  - Legitimate API calls to external cloud controllers or update servers
level: high

// Hunt for suspicious process spawns on Linux endpoints hosting vManage
DeviceProcessEvents  
| where Timestamp > ago(7d)
| where DeviceName has "vManage" or DeviceCustomEntityType has "SD-WAN"
| where InitiatingProcessFileName in ("java", "nginx", "httpd")
| where FileName in ("sh", "bash", "dash", "perl", "python", "nc")
| project Timestamp, DeviceName, AccountName, InitiatingProcessCommandLine, CommandLine, FolderPath
| extend Tactic = "Execution"

-- Hunt for web service spawning shells on vManage appliances
SELECT Pid, Name, CommandLine, Exe, Username, Parent.Pid AS ParentPid, Parent.Name AS ParentName, Parent.CommmandLine AS ParentCmd
FROM pslist()
WHERE ParentName =~ 'java' OR ParentName =~ 'nginx'
  AND Name =~ 'sh' OR Name =~ 'bash' OR Name =~ 'dash'

#!/bin/bash
# Remediation Script: Cisco Catalyst SD-WAN Manager - CVE-2026-20245
# Purpose: Check current version and recommend action.

# Check if running as root
if [ "$EUID" -ne 0 ]; then 
  echo "Please run as root"
  exit
fi

echo "[+] Checking Cisco Catalyst SD-WAN Manager Version..."

# vManage version check command (may vary by specific release, generic example)
# Adjust the command below based on your specific deployment (e.g., 'show version' CLI or API call)
VERSION_FILE="/usr/share/vmanage/.version"

if [ -f "$VERSION_FILE" ]; then
  CURRENT_VERSION=$(cat $VERSION_FILE)
  echo "[*] Detected Version: $CURRENT_VERSION"
else
  # Fallback to process check if file not found
  CURRENT_VERSION=$(dpkg -l | grep vmanage | awk '{print $3}')
  echo "[*] Detected Version via dpkg: $CURRENT_VERSION"
fi

echo "[!] ACTION REQUIRED: CVE-2026-20245 (CVSS 7.8) is actively exploited."
echo "[!] Please navigate to the Cisco Security Advisory and upgrade immediately."
echo "[!] Advisory URL: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-" # Placeholder URL structure

echo "[+] Checking for active webshells (Temp directories)..."
find /tmp /var/tmp -maxdepth 2 -type f -name ".*" -o -name "*.jsp" 2>/dev/null | head -n 5

echo "[+] Remediation Script Complete. Please verify patch application."