Detection rules › Sigma

Potential DLL Sideloading Of Libcurl.DLL Via GUP.EXE

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

Detects potential DLL sideloading of "libcurl.dll" by the "gup.exe" process from an uncommon location

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 7: Image loaded

Rule body

title: Potential DLL Sideloading Of Libcurl.DLL Via GUP.EXE
id: e49b5745-1064-4ac1-9a2e-f687bc2dd37e
status: test
description: Detects potential DLL sideloading of "libcurl.dll" by the "gup.exe" process from an uncommon location
references:
    - https://labs.withsecure.com/publications/fin7-target-veeam-servers
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-05
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith: '\gup.exe'
        ImageLoaded|endswith: '\libcurl.dll'
    filter_main_notepad_plusplus:
        Image|endswith: '\Notepad++\updater\GUP.exe'
    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: '\gup.exe'
    ImageLoaded|endswith: '\libcurl.dll'

Stage 2: not filter_main_notepad_plusplus

filter_main_notepad_plusplus:
    Image|endswith: '\Notepad++\updater\GUP.exe'

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
Imageends_with\Notepad++\updater\GUP.exeexcludes:Image field:"Image" value:"\Notepad++\updater\GUP.exe"

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Imageends_with
  • \gup.exe corpus 5 (sigma 5)
field:"Image" kind:ends_with value:"\gup.exe"
ImageLoadedends_with
  • \libcurl.dll
field:"ImageLoaded" kind:ends_with value:"\libcurl.dll"