Known false positives
- Legitimate third party application located in "AppData" may leverage this DLL to offer 7z compression functionality and may generate false positives. Apply additional filters as needed.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | |
| Stealth |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 7: Image loaded |
Rule body
title: Potential 7za.DLL Sideloading
id: 4f6edb78-5c21-42ab-a558-fd2a6fc1fd57
status: test
description: Detects potential DLL sideloading of "7za.dll"
references:
- https://www.gov.pl/attachment/ee91f24d-3e67-436d-aa50-7fa56acf789d
author: X__Junior
date: 2023-06-09
tags:
- attack.persistence
- attack.privilege-escalation
- attack.execution
- attack.stealth
- attack.t1574.001
logsource:
category: image_load
product: windows
detection:
selection:
ImageLoaded|endswith: '\7za.dll'
filter_main_legit_path:
Image|startswith:
- 'C:\Program Files (x86)\'
- 'C:\Program Files\'
ImageLoaded|startswith:
- 'C:\Program Files (x86)\'
- 'C:\Program Files\'
condition: selection and not 1 of filter_main_*
falsepositives:
- Legitimate third party application located in "AppData" may leverage this DLL to offer 7z compression functionality and may generate false positives. Apply additional filters as needed.
level: low
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_*Stage 1: selection
selection:
ImageLoaded|endswith: '\7za.dll'
Stage 2: not filter_main_legit_path
filter_main_legit_path:
Image|startswith:
- 'C:\Program Files (x86)\'
- 'C:\Program Files\'
ImageLoaded|startswith:
- 'C:\Program Files (x86)\'
- 'C:\Program Files\'
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
Image | starts_with | C:\Program Files (x86)\ | excludes:Image field:"Image" value:"C:\Program Files (x86)\" |
Image | starts_with | C:\Program Files\ | excludes:Image field:"Image" value:"C:\Program Files\" |
ImageLoaded | starts_with | C:\Program Files (x86)\ | excludes:ImageLoaded field:"ImageLoaded" value:"C:\Program Files (x86)\" |
ImageLoaded | starts_with | C:\Program Files\ | excludes:ImageLoaded field:"ImageLoaded" value:"C:\Program Files\" |
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
ImageLoaded | ends_with |
| field:"ImageLoaded" kind:ends_with value:"\7za.dll" |