OVSwrap Linux Kernel Flaw: Local Root via Open vSwitch — Detection & Defense

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title: Potential OVSwrap Exploit - Non-Root OVS Tool Execution
id: a9b8c7d6-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects execution of Open vSwitch utilities (ovs-vsctl, ovs-dpctl) by non-root users, which is unusual and may indicate an attempt to interact with the kernel module for exploitation.
references:
 - https://securityarsenal.com/intel/ovswrap-2026
author: Security Arsenal
date: 2026/08/15
tags:
  - attack.privilege_escalation
  - attack.t1068
logsource:
  category: process_creation
  product: linux
detection:
  selection_tools:
    Image|endswith:
      - '/ovs-vsctl'
      - '/ovs-dpctl'
      - '/ovs-appctl'
  selection_non_root:
    User|startswith:
      - 'user'
      - 'nobody'
      - 'ubuntu'
      - 'www-data'
  filter_root:
    User: 'root'
  condition: selection_tools and selection_non_root and not filter_root
falsepositives:
  - Legitimate administration by non-root users via sudo (sudo usually logs as root, but check specific logging configurations)
level: high
---
title: OVSwrap Exploit Development - GCC with OVS Headers
id: b0c9d8e7-6f5a-4b3c-2d1e-0f9e8d7c6b5a
status: experimental
description: Detects compilation of C code including Open vSwitch kernel headers by non-root users, a strong indicator of local exploit development for OVSwrap.
author: Security Arsenal
date: 2026/08/15
tags:
  - attack.defense_evasion
  - attack.t1059.004
logsource:
  category: process_creation
  product: linux
detection:
  selection_gcc:
    Image|endswith:
      - '/gcc'
      - '/cc'
      - '/clang'
  selection_headers:
    CommandLine|contains:
      - '-I/usr/include/openvswitch'
      - 'openvswitch/types.h'
  selection_non_root:
    User|contains:
      - 'user'
      - 'app'
  condition: selection_gcc and selection_headers and selection_non_root
falsepositives:
  - Legitimate OVS plugin development by developers (Rare in production)
level: critical

// Hunt for suspicious Netlink socket creation (Syslog/Auditd)
// OVSwrap uses Netlink to communicate with the kernel module. Excessive creation or attempts by low-priv users is suspicious.
Syslog
| where ProcessName == "auditd" 
| extend SyslogMessageData = extract_all_regex(@'\{.*?\}', SyslogMessage)[0]
| parse SyslogMessage with * "type=SYSCALL" * "arch=" Arch "syscall=" SyscallNo "success=" Success * "exit=" ExitCode * "items=" ItemCount * "pid=" Pid * "comm=" ProcessName * "exe=" ExePath *
| where SyscallNo == "41" // syscall 41 is often socket on x86_64, context dependent, or use Auditd event type for socket
| where ExePath !contains "/usr/sbin/" and ExePath !contains "/usr/bin/"
| project TimeGenerated, Computer, ProcessName, ExePath, SyslogMessage
| summarize count() by Computer, ProcessName, ExePath
| where count_ > 10

// Hunt for OVS userspace tool execution
DeviceProcessEvents 
| where FileName in~ ("ovs-vsctl", "ovs-dpctl", "ovs-ofctl")
| where AccountName != "root" and AccountName !contains "$")
| project Timestamp, DeviceName, AccountName, FileName, ProcessCommandLine

-- Hunt for OVS Module status and suspicious processes
SELECT 
  Mod.Name AS ModuleName,
  Mod.Size AS ModuleSize,
  Mod.Status AS Status
FROM loaded_modules()
WHERE Name =~ "openvswitch"

-- Hunt for processes attempting to interact with tun/ovs devices
SELECT 
  Pid, 
  Name, 
  Username, 
  Exe,
  CommandLine
FROM pslist()
WHERE Name =~ 'ovs'
  AND Username != 'root'

-- Check for common exploit artifact names in /tmp or /dev/shm
SELECT FullPath, Size, Mtime
FROM glob(globs="/tmp/*ovs*, /dev/shm/*ovs*, /tmp/exploit*, /dev/shm/exploit*")

#!/bin/bash

# OVSwrap Remediation & Verification Script
# Run as root

LOG_FILE="/var/log/ovswrap_remediation.log"
echo "Starting OVSwrap remediation check..." | tee -a $LOG_FILE

# 1. Check if Open vSwitch kernel module is loaded
if lsmod | grep -q "^openvswitch "; then
    echo "[ALERT] Open vSwitch kernel module is currently LOADED." | tee -a $LOG_FILE
    
    # 2. Check if we can safely unload (Stopping OVS services)
    if systemctl is-active --quiet openvswitch || systemctl is-active --quiet ovs-vswitchd; then
        echo "[ACTION] Stopping Open vSwitch services..." | tee -a $LOG_FILE
        systemctl stop openvswitch
        systemctl stop ovs-vswitchd
    fi

    # 3. Unload the kernel module (Immediate Mitigation if patch not available)
    echo "[ACTION] Unloading openvswitch kernel module..." | tee -a $LOG_FILE
    modprobe -r openvswitch
    if [ $? -eq 0 ]; then
        echo "[SUCCESS] Module unloaded successfully." | tee -a $LOG_FILE
    else
        echo "[ERROR] Failed to unload module. It may be in use." | tee -a $LOG_FILE
    fi
else
    echo "[INFO] Open vSwitch kernel module is NOT loaded. System is not immediately vulnerable via kernel vector." | tee -a $LOG_FILE
fi

# 4. Check Kernel Version (Verify against vendor advisories)
KERNEL_VER=$(uname -r)
echo "[INFO] Current Kernel Version: $KERNEL_VER" | tee -a $LOG_FILE

echo "[REMEDIATION] Please update your kernel to the latest version provided by your distribution vendor to patch OVSwrap." | tee -a $LOG_FILE
echo "[REMEDIATION] Vendor Advisory tracking: Search your distro's security advisory for 'OVSwrap' or 'Open vSwitch Privilege Escalation'." | tee -a $LOG_FILE


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