Detect Adversary-in-the-Middle in Google Chronicle
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as Network Sniffing (T1040), Transmitted Data Manipulation (T1565.002), or replay attacks. By abusing features of common networking protocols (ARP, DNS, LLMNR, DHCP), adversaries force devices to communicate through an adversary-controlled system to harvest credentials, session tokens, and sensitive data. Sub-techniques include LLMNR/NBT-NS Poisoning and SMB Relay (T1557.001), ARP Cache Poisoning (T1557.002), DHCP Spoofing (T1557.003), and Evil Twin wireless attacks (T1557.004). Common attack frameworks include Responder, Bettercap, Ettercap, ntlmrelayx, mitmproxy, dnschef, and EvilGinx2. Threat groups including Kimsuky, Sea Turtle, and Mustang Panda have leveraged AiTM positioning for large-scale credential theft, session hijacking, and DNS record manipulation at service providers.
MITRE ATT&CK
- Tactic
- Credential Access Collection
- Technique
- T1557 Adversary-in-the-Middle
- Canonical reference
- https://attack.mitre.org/techniques/T1557/
YARA-L Detection Query
rule aitm_tool_execution_t1557 {
meta:
author = "Argus Detection Engineering"
description = "Detects execution of known Adversary-in-the-Middle (AiTM) tools including Responder, Bettercap, Ettercap, mitmproxy, ntlmrelayx, dnschef, mitm6, and EvilGinx2. Also detects DNS config modification via netsh and PowerShell. Maps to MITRE ATT&CK T1557 and sub-techniques T1557.001, T1557.002, T1557.003."
mitre_attack_tactic = "Collection, Credential Access"
mitre_attack_technique = "T1557"
severity = "HIGH"
priority = "HIGH"
events:
$e.metadata.event_type = "PROCESS_LAUNCH"
(
re.regex($e.principal.process.file.full_path, `(?i)(responder\.exe|bettercap|bettercap\.exe|ettercap|ettercap\.exe|mitmproxy|mitmdump|mitmweb|dnschef|sslstrip|evilginx|evilginx2|mitm6)`) OR
re.regex($e.target.process.command_line, `(?i)(responder|ntlmrelayx|smbrelayx|multirelay|impacket-ntlmrelayx|bettercap|ettercap|arpspoof|arp-spoof|mitmproxy|mitmdump|mitmweb|sslstrip|dnschef|mitm6|evilginx|set-dnsclientserveraddress)`) OR
(
re.regex($e.principal.process.file.full_path, `(?i)(python\.exe|python3\.exe|python3)`) AND
re.regex($e.target.process.command_line, `(?i)(ntlmrelayx|smbrelayx|responder|mitm6|dnschef|evilginx|bettercap)`)
) OR
(
re.regex($e.principal.process.file.full_path, `(?i)\\arp\.exe`) AND
re.regex($e.target.process.command_line, `(?i)\s-s\s`)
) OR
(
re.regex($e.principal.process.file.full_path, `(?i)\\netsh\.exe`) AND
re.regex($e.target.process.command_line, `(?i)(interface.*dns.*set|int.*ip.*set.*dns)`)
) OR
(
re.regex($e.principal.process.file.full_path, `(?i)\\powershell\.exe`) AND
re.regex($e.target.process.command_line, `(?i)set-dnsclientserveraddress`)
)
)
condition:
$e
}Chronicle YARA-L 2.0 rule detecting AiTM tool execution by matching process launch events against known AiTM tool names and command-line keywords using UDM field model. Covers LLMNR/NBT-NS relay, ARP poisoning, SSL interception, DNS spoofing, and DNS configuration modification attack patterns.
Data Sources
Required Tables
False Positives & Tuning
- Red team operators conducting authorized adversary simulation exercises with Responder or Bettercap
- Network administrators modifying DNS server settings via netsh or PowerShell during approved change windows
- Security researchers using mitmproxy or sslstrip for web application security assessments
- Python-based automation scripts that include argument strings matching AiTM tool names
Other platforms for T1557
Testing Methodology
Validate this detection against 5 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1ARP Static Entry Manipulation (Windows)
Expected signal: Sysmon Event ID 1: Process Create with Image=C:\Windows\System32\arp.exe, CommandLine='arp -s 192.168.100.254 00-AA-BB-CC-DD-EE'. Security Event ID 4688 (if command-line auditing is enabled). No network events expected as this is a local table modification.
- Test 2DNS Server Change via netsh (Windows)
Expected signal: Sysmon Event ID 1: Process Create with Image=C:\Windows\System32\netsh.exe, CommandLine containing 'interface ip set dns'. Sysmon Event ID 13: Registry value set under HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{GUID}\NameServer with new value '127.0.0.1'.
- Test 3DNS Server Change via PowerShell (Windows)
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe, CommandLine containing 'Set-DnsClientServerAddress'. Sysmon Event ID 13: Registry modification at HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{GUID}\NameServer. PowerShell ScriptBlock Log Event ID 4104 showing the Set-DnsClientServerAddress call.
- Test 4ARP Poisoning Tool Execution — arpspoof (Linux)
Expected signal: Syslog or auditd process creation event for arpspoof. On systems with Sysmon for Linux (sysmonforlinux): Event ID 1 Process Create with Image path to arpspoof binary and CommandLine '-i lo -t 127.0.0.1 127.0.0.2'. Auditd syscall records for execve with the arpspoof arguments.
- Test 5mitmproxy SSL Interception Tool Invocation (Linux/macOS)
Expected signal: Process creation event for mitmproxy binary (path varies by pip install location, typically ~/.local/bin/mitmproxy or /usr/local/bin/mitmproxy). Sysmon Event ID 1 (if Sysmon for Linux deployed) with Image containing 'mitmproxy' and CommandLine '--version'. Auditd EXECVE syscall record.
References (12)
- https://attack.mitre.org/techniques/T1557/
- https://www.rapid7.com/fundamentals/man-in-the-middle-attacks/
- https://github.com/lgandx/Responder
- https://www.bettercap.org/
- https://github.com/mitmproxy/mitmproxy
- https://github.com/kgretzky/evilginx2
- https://github.com/fox-it/mitm6
- https://www.microsoft.com/en-us/security/blog/2022/11/16/token-tactics-how-to-prevent-detect-and-respond-to-cloud-token-theft/
- https://blog.talosintelligence.com/sea-turtle/
- https://github.com/SecureAuthCorp/impacket/blob/master/impacket/examples/ntlmrelayx/
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceregistryevents-table
- https://learn.microsoft.com/en-us/windows-server/networking/technologies/ipam/dns-resource-record-management
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