Detection rules › Sigma

HackTool - HollowReaper Execution

Status
experimental
Severity
high
Log source
product windows, category process_creation
Author
Swachchhanda Shrawan Poudel (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects usage of HollowReaper, a process hollowing shellcode launcher used for stealth payload execution through process hollowing. It replaces the memory of a legitimate process with custom shellcode, allowing the attacker to execute payloads under the guise of trusted binaries.

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: HackTool - HollowReaper Execution
id: 85d23b42-9a9d-4f8f-b3d7-d2733c1d58f5
status: experimental
description: |
    Detects usage of HollowReaper, a process hollowing shellcode launcher used for stealth payload execution through process hollowing.
    It replaces the memory of a legitimate process with custom shellcode, allowing the attacker to execute payloads under the guise of trusted binaries.
references:
    - https://github.com/vari-sh/RedTeamGrimoire/tree/b5e7635d34db6e1f0398d8847e8f293186e947c5/HollowReaper
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-07-01
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055.012
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\HollowReaper.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\HollowReaper.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \HollowReaper.exe