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Detection rules › Sigma

Local File Read Using Curl.EXE

Status
test
Severity
medium
Log source
product windows, category process_creation
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects execution of "curl.exe" with the "file://" protocol handler in order to read local files.

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Local File Read Using Curl.EXE
id: aa6f6ea6-0676-40dd-b510-6e46f02d8867
status: test
description: Detects execution of "curl.exe" with the "file://" protocol handler in order to read local files.
references:
    - https://curl.se/docs/manpage.html
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-07-27
tags:
    - attack.execution
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\curl.exe'
        - OriginalFileName: 'curl.exe'
    selection_cli:
        CommandLine|contains: 'file:///'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_curl_local_file_read/info.yml

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith: '\curl.exe'
    - OriginalFileName: 'curl.exe'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains: 'file:///'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • file:///
Imageends_with
  • \curl.exe corpus 30 (sigma 30)
OriginalFileNameeq
  • curl.exe corpus 15 (sigma 12, splunk 3)