CVE-2026-59726: Ruflo MCP Unauthenticated RCE & AI Poisoning — Detection Guide

---
title: Ruflo MCP Spawning Reverse Shell
id: 550d9a23-0f72-4e3a-a8c5-1d2f3b4c5d6e
status: experimental
description: Detects Ruflo harness spawning suspicious network shells or scripting interpreters, indicative of CVE-2026-59726 exploitation.
references:
  - https://noma.security/blog/rufroot-disclosure
author: Security Arsenal
date: 2026/07/15
tags:
  - attack.execution
  - attack.t1059.004
logsource:
  category: process_creation
  product: linux
detection:
  selection_parent:
    ParentImage|endswith: '/ruflo'
    OR ParentImage|contains: 'python'
    OR ParentImage|contains: 'node'
    ParentCommandLine|contains: 'ruflo'
  selection_child:
    Image|endswith:
      - '/bash'
      - '/sh'
      - '/nc'
      - '/python'
      - '/perl'
    CommandLine|contains:
      - ' -i >& /dev/tcp/'
      - ' /dev/tcp/'
      - 'exec 5<>/dev/tcp/'
  condition: all of selection_*
falsepositives:
  - Legitimate developer usage of Ruflo for system administration
level: high
---
title: Ruflo MCP Outbound Network Connection to Non-Local Address
id: 7a3f1c82-9e4b-4d67-bc12-3e5a8f901234
status: experimental
description: Detects the Ruflo agent establishing outbound connections to external IPs, which violates standard MCP local-only usage patterns.
references:
  - https://noma.security/blog/rufroot-disclosure
author: Security Arsenal
date: 2026/07/15
tags:
  - attack.command_and_control
  - attack.t1071
logsource:
  category: network_connection
  product: linux
detection:
  selection:
    Image|endswith: '/ruflo'
    OR Image|contains: 'python'
    Initiated: 'true'
  filter:
    DestinationIp|startswith:
      - '127.'
      - '10.'
      - '192.168.'
      - '172.16.'
      - '169.254.'
      - '::1'
  condition: selection and not filter
falsepositives:
  - Ruflo configured to access external APIs legitimately
level: medium

// Hunt for Ruflo process spawning suspicious shells or outbound connections
let SuspiciousCommands = dynamic(["bash", "sh", "nc", "python3", "perl"]);
let RufloProcesses = DeviceProcessEvents
| where Timestamp > ago(1d)
| where InitiatingProcessFileName has "ruflo" or InitiatingProcessCommandLine has "ruflo";
// Check for shell spawning
RufloProcesses
| where FileName in (SuspiciousCommands)
  or ProcessCommandLine has "/dev/tcp/"
  or ProcessCommandLine has "&>"
| project Timestamp, DeviceName, AccountName, InitiatingProcessCommandLine, ProcessCommandLine, FileName
| order by Timestamp desc
;
// Check for network connections
DeviceNetworkEvents
| where Timestamp > ago(1d)
| where InitiatingProcessFileName has "ruflo"
| where RemoteIP !startswith "127."
  and RemoteIP !startswith "192.168."
  and RemoteIP !startswith "10."
  and RemoteIP !startswith "172.16."
  and RemoteIP !startswith "169.254."
| project Timestamp, DeviceName, InitiatingProcessAccountName, RemoteIP, RemotePort, RemoteUrl
| order by Timestamp desc

-- Hunt for Ruflo processes and their open network sockets
SELECT Pid, Name, Exe, CommandLine, Username
FROM pslist()
WHERE Name =~ 'ruflo'
   OR CommandLine =~ 'ruflo'

-- Cross-reference with network connections for the same PIDs
SELECT Pid, Family, RemoteAddress, RemotePort, State
FROM netstat()
WHERE Pid IN (
    SELECT Pid
    FROM pslist()
    WHERE Name =~ 'ruflo'
)
  AND (RemoteAddress NOT IN ('127.0.0.1', '::1', '0.0.0.0') 
       AND NOT RemoteAddress =~ '^10\.' 
       AND NOT RemoteAddress =~ '^192\.168\.' 
       AND NOT RemoteAddress =~ '^172\.1[6-9]\.' 
       AND NOT RemoteAddress =~ '^172\.2[0-9]\.' 
       AND NOT RemoteAddress =~ '^172\.3[0-1]\.')

#!/bin/bash
# Remediation script for CVE-2026-59726 (Ruflo MCP)
# Checks for running Ruflo processes and verifies version >= 3.16.3

# Function to check version (Assumes 'ruflo --version' is available, adjust if using pip/venv)
check_ruflo_version() {
    if command -v ruflo &> /dev/null; then
        INSTALLED_VERSION=$(ruflo --version 2>&1 | grep -oP '\d+\.\d+\.\d+' | head -1)
        echo "[+] Ruflo version detected: $INSTALLED_VERSION"
        
        # Simple string comparison for version
        if [ "$(printf '%s\n' "3.16.3" "$INSTALLED_VERSION" | sort -V | head -n1)" != "3.16.3" ]; then
            echo "[ALERT] CVE-2026-59726: Version $INSTALLED_VERSION is vulnerable."
            return 1
        else
            echo "[OK] Version $INSTALLED_VERSION is patched."
            return 0
        fi
    else
        echo "[-] Ruflo binary not found in PATH. Searching for python processes..."
        # Fallback: Check for python processes running ruflo libraries
        if pgrep -f "ruflo" > /dev/null; then
            echo "[ALERT] Ruflo processes are running but version check failed. Manual audit required."
            ps aux | grep ruflo
            return 1
        fi
        echo "[OK] No Ruflo processes detected."
        return 0
    fi
}

check_ruflo_version

# If vulnerable, advise on update and immediate kill
if [ $? -ne 0 ]; then
    echo "[ACTION REQUIRED] Kill existing Ruflo processes immediately."
    pkill -f "ruflo"
    echo "[REMEDIATION] Upgrade Ruflo to version 3.16.3 or later immediately."
    echo "Example: pip install ruflo --upgrade || pip install ruflo==3.16.3"
fi