Sigma Rule Library

Self Extraction Directive File Created In Potentially Suspicious Location

Detects the creation of Self Extraction Directive files (.sed) in a potentially suspicious location. These files are used by the "iexpress.exe" utility in order to create self extracting packages. Attackers were seen abusing this utility and creating PE files with embedded ".sed" entries.

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Detection logic

selection

TargetFilename|contains:
  - :\ProgramData\
  - :\Temp\
  - :\Windows\System32\Tasks\
  - :\Windows\Tasks\
  - :\Windows\Temp\
  - \AppData\Local\Temp\
TargetFilename|endswith: .sed

Condition

selection

Raw YAML

title: Self Extraction Directive File Created In Potentially Suspicious Location
id: 760e75d8-c3b5-409b-a9bf-6130b4c4603f
related:
    - id: ab90dab8-c7da-4010-9193-563528cfa347
      type: derived
status: test
description: |
    Detects the creation of Self Extraction Directive files (.sed) in a potentially suspicious location.
    These files are used by the "iexpress.exe" utility in order to create self extracting packages.
    Attackers were seen abusing this utility and creating PE files with embedded ".sed" entries.
references:
    - https://strontic.github.io/xcyclopedia/library/iexpress.exe-D594B2A33EFAFD0EABF09E3FDC05FCEA.html
    - https://en.wikipedia.org/wiki/IExpress
    - https://www.virustotal.com/gui/file/602f4ae507fa8de57ada079adff25a6c2a899bd25cd092d0af7e62cdb619c93c/behavior
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2024-02-05
tags:
    - attack.stealth
    - attack.t1218
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|contains:
            - ':\ProgramData\'
            - ':\Temp\'
            - ':\Windows\System32\Tasks\'
            - ':\Windows\Tasks\'
            - ':\Windows\Temp\'
            - '\AppData\Local\Temp\'
        TargetFilename|endswith: '.sed'
    condition: selection
falsepositives:
    - Unknown
level: medium

False positives

  • Unknown

References

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