Suspicious HWP Sub Processes

SIGMA detection rule by Florian Roth (Nextron Systems) · NOASSERTION

Detects suspicious Hangul Word Processor (Hanword) sub processes that could indicate an exploitation

title: Suspicious HWP Sub Processes
id: 023394c4-29d5-46ab-92b8-6a534c6f447b
status: test
description: Detects suspicious Hangul Word Processor (Hanword) sub processes that could indicate an exploitation
references:
    - https://www.securitynewspaper.com/2016/11/23/technical-teardown-exploit-malware-hwp-files/
    - https://www.hybrid-analysis.com/search?query=context:74940dcc5b38f9f9b1a0fea760d344735d7d91b610e6d5bd34533dd0153402c5&from_sample=5db135000388385a7644131f&block_redirect=1
    - https://twitter.com/cyberwar_15/status/1187287262054076416
    - https://blog.alyac.co.kr/1901
    - https://en.wikipedia.org/wiki/Hangul_(word_processor)
author: Florian Roth (Nextron Systems)
date: 2019-10-24
modified: 2021-11-27
tags:
    - attack.initial-access
    - attack.t1566.001
    - attack.execution
    - attack.t1203
    - attack.t1059.003
    - attack.g0032
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\Hwp.exe'
        Image|endswith: '\gbb.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

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

86e1bd78-45c8-4082-97db-83ba062fed5d

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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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