Windows Execution of IOX (iex/port forwarding) Tunnel/Proxy Tool via Process Creation

Alerts on Windows process creation for iox.exe with tunneling/proxy forwarding command-line parameters.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-10-08
Updated: 2026-07-30

ATT&CK techniques

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1090Proxy
Exfiltration
Impact

What it detects

This rule flags execution of iox.exe on Windows when the command line includes port forwarding and intranet proxy parameters. Attackers may use tunneling tools to route traffic through compromised hosts and reach internal services while hiding the true origin. It relies on process creation telemetry, including the executed image path, command line arguments, and optional file hash matches to confirm the tool.

Reporting behind it

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Windows Execution of IOX (iex/port forwarding) Tunnel/Proxy Tool via Process Creation

Pivot detection · T1090 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-execution-of-iox-iex-port-forwarding-tunnel-proxy-tool-via-process-creat-d7654f02

title: Windows Execution of IOX (iex/port forwarding) Tunnel/Proxy Tool via Process Creation
id: 4408c537-2e91-45d8-9c94-6c4033e16f84
status: test
description: This rule flags execution of iox.exe on Windows when the command line includes port forwarding and intranet proxy parameters. Attackers may use tunneling tools to route traffic through compromised hosts and reach internal services while hiding the true origin. It relies on process creation telemetry, including the executed image path, command line arguments, and optional file hash matches to confirm the tool.
references:
  - https://github.com/EddieIvan01/iox
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_pua_iox.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-10-08
modified: 2024-11-23
tags:
  - attack.command-and-control
  - attack.t1090
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: \iox.exe
  selection_commandline:
    CommandLine|contains:
      - ".exe fwd -l "
      - ".exe fwd -r "
      - ".exe proxy -l "
      - ".exe proxy -r "
  selection_hashes:
    Hashes|contains:
      - MD5=9DB2D314DD3F704A02051EF5EA210993
      - SHA1=039130337E28A6623ECF9A0A3DA7D92C5964D8DD
      - SHA256=C6CF82919B809967D9D90EA73772A8AA1C1EB3BC59252D977500F64F1A0D6731
  condition: 1 of selection*
falsepositives:
  - Legitimate use
level: high
license: DRL-1.1
related:
  - id: d7654f02-e04b-4934-9838-65c46f187ebc
    type: derived

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