New Self Extracting Package Created Via IExpress.EXE

Description

Detects the "iexpress.exe" utility creating self-extracting packages. Attackers where seen leveraging "iexpress" to compile packages on the fly via ".sed" files. Investigate the command line options provided to "iexpress" and in case of a ".sed" file, check the contents and legitimacy of it.

Query · sigma

selection_1_parent:
  ParentImage|endswith: \iexpress.exe
selection_1_img:
- Image|endswith: \makecab.exe
- OriginalFileName: makecab.exe
selection_2_img:
- Image|endswith: \iexpress.exe
- OriginalFileName: IEXPRESS.exe
selection_2_cli:
  CommandLine|contains: ' /n '
condition: all of selection_1_* or all of selection_2_*

Known false positives

  • Administrators building packages using iexpress.exe
Raw source New Self Extracting Package Created Via IExpress.EXE · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: New Self Extracting Package Created Via IExpress.EXE
id: c2b478fc-09bf-40b2-8768-ab3ec8d61c9a
status: test
description: |
    Detects the "iexpress.exe" utility creating self-extracting packages.
    Attackers where seen leveraging "iexpress" to compile packages on the fly via ".sed" files.
    Investigate the command line options provided to "iexpress" and in case of a ".sed" file, check the contents and legitimacy of it.
references:
    - https://strontic.github.io/xcyclopedia/library/iexpress.exe-D594B2A33EFAFD0EABF09E3FDC05FCEA.html
    - https://en.wikipedia.org/wiki/IExpress
    - https://decoded.avast.io/janvojtesek/raspberry-robins-roshtyak-a-little-lesson-in-trickery/
    - https://www.virustotal.com/gui/file/602f4ae507fa8de57ada079adff25a6c2a899bd25cd092d0af7e62cdb619c93c/behavior
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2024-02-05
tags:
    - attack.stealth
    - attack.t1218
    - detection.threat-hunting
logsource:
    category: process_creation
    product: windows
detection:
    selection_1_parent:
        ParentImage|endswith: '\iexpress.exe'
    selection_1_img:
        - Image|endswith: '\makecab.exe'
        - OriginalFileName: 'makecab.exe'
    selection_2_img:
        - Image|endswith: '\iexpress.exe'
        - OriginalFileName: 'IEXPRESS.exe'
    selection_2_cli:
        CommandLine|contains: ' /n '
    condition: all of selection_1_* or all of selection_2_*
falsepositives:
    - Administrators building packages using iexpress.exe
level: medium

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