AudiA6 Botnet Takedown and ICS Exposure: Operational Defense Briefing

---
title: Potential AudiA6 Botnet Agent Activity
id: 8a1b2c3d-4e5f-6789-0a1b-2c3d4e5f6789
status: experimental
description: Detects process execution or network activity associated with the AudiA6 botnet based on known naming conventions or C2 beacon patterns.
references:
 - https://www.securityweek.com/in-other-news-google-security-layoffs-audia6-takedown-400-million-coupang-fine/
author: Security Arsenal
date: 2026/04/06
tags:
 - attack.command_and_control
 - attack.t1071.001
logsource:
 category: process_creation
 product: linux
detection:
 selection:
   Image|endswith:
     - '/audi.a6'
     - '/a6'
     - '/systemd-network' # Common masquerade
   or
   CommandLine|contains:
     - 'AudiA6'
     - 'audi.c'
 condition: selection
falsepositives:
 - Legitimate automotive diagnostic tools (rare on servers)
level: high
---
title: ICS Protocol Exposure on Non-Standard Interface
description: Detects ICS protocols (Modbus) communicating on non-internal interfaces, indicating potential exposure or unauthorized pivoting.
id: 9b2c3d4e-5f6a-7890-1b2c-3d4e5f67890a
status: experimental
author: Security Arsenal
date: 2026/04/06
tags:
 - attack.initial_access
 - attack.t1190
logsource:
 category: network_connection
 product: windows
detection:
 selection:
   DestinationPort: 502
   Initiated: 'true'
 filter:
   DestinationIp|cidr:
     - '10.0.0.0/8'
     - '172.16.0.0/12'
     - '192.168.0.0/16'
 condition: selection and not filter
falsepositives:
 - Authorized engineering workstations connecting to local PLCs
level: medium

// Hunt for AudiA6 related process strings or network connections
// hunting for generic botnet behavior often associated with AudiA6
DeviceProcessEvents
| where Timestamp > ago(7d)
| where ProcessVersionInfoOriginalFileName =~ "unknown" or ProcessVersionInfoCompanyName =~ "unknown"
| where ProcessCommandLine has "AudiA6" 
   or ProcessCommandLine has "audi" 
   or ProcessCommandLine has ".c" // C compiled bots often use .c refs in args
| project Timestamp, DeviceName, FileName, ProcessCommandLine, InitiatingProcessFileName
| extend DocId = strcat(DeviceName, FileName)
;

// Correlate with Network Connections for outbound C2
DeviceNetworkEvents
| where Timestamp > ago(7d)
| where RemotePort in (80, 443, 8080) 
| where InitiatingProcessCommandLine has "AudiA6" or InitiatingProcessFileName has "a6"
| summarize Count() by DeviceName, RemoteUrl, RemoteIP

-- Hunt for AudiA6 binaries or suspicious cron jobs (common persistence for Linux bots)
SELECT 
  FullPath, 
  Size, 
  Mtime, 
  Mode.String
FROM glob(globs="/bin/*", root="/")
WHERE Name =~ "a6" 
   OR Name =~ "audi"
   OR Mtime > now() - timedelta(days=7)

-- Hunt for suspicious established network connections (Potential C2)
SELECT 
  Family, 
  RemoteAddr, 
  RemotePort, 
  State, 
  Pid, 
  Username
FROM netstat()
WHERE State = "ESTABLISHED" 
  AND RemotePort > 1024
  AND LocalAddr != "127.0.0.1" 
  AND LocalAddr != "::1"

#!/bin/bash

# AudiA6 Botnet Remediation and ICS Exposure Check
# Run with elevated privileges

AUDIA6_INDICATORS=("/tmp/a6" "/var/tmp/audi.a6" "/dev/shm/a6")

echo "[+] Scanning for known AudiA6 artifacts..."

for indicator in "${AUDIA6_INDICATORS[@]}"; do
    if [ -f "$indicator" ]; then
        echo "[!] Found suspicious artifact: $indicator"
        # Get PID if running
        pid=$(pgrep -f "$(basename $indicator)")
        if [ ! -z "$pid" ]; then
            echo "[!] Killing process $pid..."
            kill -9 "$pid"
        fi
        echo "[!] Removing file $indicator..."
        rm -f "$indicator"
    fi
done

# Check for common persistence mechanisms (Cron)
echo "[+] Checking for suspicious cron jobs..."
crontab -l 2>/dev/null | grep -i "audi" && echo "[!] Suspicious cron entry found."

# ICS Exposure Check (Simple Netstat for Modbus - Port 502)
echo "[+] Checking for ICS Modbus exposure (Port 502)..."
if netstat -tuln 2>/dev/null | grep -q ":502 "; then
    echo "[!] WARNING: Port 502 (Modbus) is listening. Verify binding interface."
    netstat -tuln | grep ":502 "
else
    echo "[-] Port 502 not listening."
fi

echo "[+] Remediation checks complete."