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Wget Creating Files in Tmp Directory — Sigma Rule

Sigma rule 35a05c60-9012-49b6-a11f-6bab741c9f74. Wget Creating Files in Tmp Directory — Sigma Rule. Detects the use of wget to download content in a temporary directory such as "/tmp" or "/var/tmp"

Rule metadata and linked tags

testmediumlinuxfile_eventattack.command-and-controlattack.t1105

Author: Joseliyo Sanchez, @Joseliyo_Jstnk. Source status: test; severity: medium. Source dates: 2023-06-02 / not supplied.

{
  "product": "linux",
  "category": "file_event"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 59c1c89c340395327df7c20cc4805925e85346ef8a1cf14f0ef6f8a75a2f6086

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Wget Creating Files in Tmp Directory
id: 35a05c60-9012-49b6-a11f-6bab741c9f74
status: test
description: Detects the use of wget to download content in a temporary directory such as "/tmp" or "/var/tmp"
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
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2023-06-02
tags:
    - attack.command-and-control
    - attack.t1105
logsource:
    product: linux
    category: file_event
detection:
    selection:
        Image|endswith: '/wget'
        TargetFilename|startswith:
            - '/tmp/'
            - '/var/tmp/'
    condition: selection
falsepositives:
    - Legitimate downloads of files in the tmp folder.
level: medium

Original YAML and metadata in JSON

False positives

  • Legitimate downloads of files in the tmp folder.

Source references

Connected ecosystem references

Exact source-tagged techniques

Telemetry review

Read the original logsource above, then inspect the linked detection workspaces for technique-level sensor context. No per-rule telemetry equivalence is inferred.

Pinned research references. No browser attack runner, live simulation result or validated detector is asserted. Source mappings and validation limits are preserved. ATT&CK / Atomic provenance · Detection provenance.