Suspicious Windows Strings In URI

SIGMA detection rule by Nasreddine Bencherchali (Nextron Systems) · NOASSERTION

Detects suspicious Windows strings in URI which could indicate possible exfiltration or webshell communication

title: Suspicious Windows Strings In URI
id: 9f6a34b4-2688-4eb7-a7f5-e39fef573d0e
status: test
description: Detects suspicious Windows strings in URI which could indicate possible exfiltration or webshell communication
references:
    - https://thedfirreport.com/2022/06/06/will-the-real-msiexec-please-stand-up-exploit-leads-to-data-exfiltration/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-06-06
modified: 2023-01-02
tags:
    - attack.persistence
    - attack.exfiltration
    - attack.t1505.003
logsource:
    category: webserver
detection:
    selection:
        cs-uri-query|contains:
            - '=C:/Users'
            - '=C:/Program%20Files'
            - '=C:/Windows'
            - '=C%3A%5CUsers'
            - '=C%3A%5CProgram%20Files'
            - '=C%3A%5CWindows'
    condition: selection
falsepositives:
    - Legitimate application and websites that use windows paths in their URL
level: high

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

05d05203-fc1d-4826-9ef8-75b828841a29

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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