Linux wget downloads to /tmp using explicit output options
Alerts on wget commands writing output to /tmp using -O or --output-document.
- Product
- linux
- Category
- process_creation
- Author
- Joseliyo Sanchez, @Joseliyo_Jstnk (SigmaHQ), DRL 1.1
- Published
- 2023-06-02
- Updated
- 2026-07-31
ATT&CK techniques
C2Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
Exfiltration
Impact
What it detects
This rule identifies Linux process executions where the image path ends with "/wget" and the command line includes output targeting indicators. It further requires explicit output-document usage (or an equivalent "-O" form) and a destination path containing "/tmp/", which can be consistent with staging files for later execution or command-and-control behavior. Telemetry relies on process creation events that include the executable path and full command line.
Reporting behind it
- blogs.jpcert.or.jphttps://blogs.jpcert.or.jp/en/2023/05/gobrat.html
- jstnk9.github.iohttps://jstnk9.github.io/jstnk9/research/GobRAT-Malware/
- virustotal.comhttps://www.virustotal.com/gui/file/60bcd645450e4c846238cf0e7226dc40c84c96eba99f6b2cffcd0ab4a391c8b3/detection
- virustotal.comhttps://www.virustotal.com/gui/file/3e44c807a25a56f4068b5b8186eee5002eed6f26d665a8b791c472ad154585d1/detection
- github.comhttps://github.com/SigmaHQ/sigma/blob/master/rules/linux/process_creation/proc_creation_lnx_wget_download_suspicious_directory.yml
Changelog
v2- v2Candidate ingested via manual entry.2026-07-31
- v1No changelog recorded for this version.2026-07-30
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
title: Linux wget downloads to /tmp using explicit output options
id: f591d06b-5133-4517-aa14-a74761e75edb
status: test
description: This rule identifies Linux process executions where the image path ends with "/wget" and the command line includes output targeting indicators. It further requires explicit output-document usage (or an equivalent "-O" form) and a destination path containing "/tmp/", which can be consistent with staging files for later execution or command-and-control behavior. Telemetry relies on process creation events that include the executable path and full command line.
references:
- https://blogs.jpcert.or.jp/en/2023/05/gobrat.html
- https://jstnk9.github.io/jstnk9/research/GobRAT-Malware/
- https://www.virustotal.com/gui/file/60bcd645450e4c846238cf0e7226dc40c84c96eba99f6b2cffcd0ab4a391c8b3/detection
- https://www.virustotal.com/gui/file/3e44c807a25a56f4068b5b8186eee5002eed6f26d665a8b791c472ad154585d1/detection
- https://github.com/SigmaHQ/sigma/blob/master/rules/linux/process_creation/proc_creation_lnx_wget_download_suspicious_directory.yml
author: Joseliyo Sanchez, @Joseliyo_Jstnk, Huntrule Team
date: 2023-06-02
tags:
- attack.command-and-control
- attack.t1105
logsource:
category: process_creation
product: linux
detection:
selection_img:
Image|endswith: /wget
selection_output:
- CommandLine|re: \s-O\s
- CommandLine|contains: --output-document
selection_path:
CommandLine|contains: /tmp/
condition: all of selection_*
falsepositives:
- Unknown
level: medium
license: DRL-1.1
related:
- id: cf610c15-ed71-46e1-bdf8-2bd1a99de6c4
type: derived