Detection rules › Sigma

Arbitrary File Download Via GfxDownloadWrapper.EXE

Status
test
Severity
medium
Log source
category process_creation, product windows
Author
Victor Sergeev, oscd.community
Source
github.com/SigmaHQ/sigma

Detects execution of GfxDownloadWrapper.exe with a URL as an argument to download file.

MITRE ATT&CK coverage

TacticTechniques
Command & Control

Telemetry coverage

Rule body

title: Arbitrary File Download Via GfxDownloadWrapper.EXE
id: eee00933-a761-4cd0-be70-c42fe91731e7
status: test
description: Detects execution of GfxDownloadWrapper.exe with a URL as an argument to download file.
references:
    - https://lolbas-project.github.io/lolbas/HonorableMentions/GfxDownloadWrapper/
author: Victor Sergeev, oscd.community
date: 2020-10-09
modified: 2023-10-18
tags:
    - attack.command-and-control
    - attack.t1105
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\GfxDownloadWrapper.exe'
        CommandLine|contains:
            - 'http://'
            - 'https://'
    filter_main_known_urls:
        CommandLine|contains: 'https://gameplayapi.intel.com/'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

selection:
    Image|endswith: '\GfxDownloadWrapper.exe'
    CommandLine|contains:
        - 'http://'
        - 'https://'

Stage 2: not filter_main_known_urls

filter_main_known_urls:
    CommandLine|contains: 'https://gameplayapi.intel.com/'

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
CommandLinematchhttps://gameplayapi.intel.com/excludes:CommandLine field:"CommandLine" value:"https://gameplayapi.intel.com/"

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • http:// corpus 23 (sigma 18, elastic 2, kusto 2, splunk 1)
  • https:// corpus 23 (sigma 18, elastic 2, kusto 2, splunk 1)
field:"CommandLine" kind:match
Imageends_with
  • \GfxDownloadWrapper.exe
field:"Image" kind:ends_with value:"\GfxDownloadWrapper.exe"