HackTool - HollowReaper Execution

Status: experimental
Severity: high
Log source: category process_creation, product windows
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

Tactic	Techniques
Privilege Escalation	`T1055.012` Process Injection: Process Hollowing
Stealth	`T1055.012` Process Injection: Process Hollowing

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

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

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\HollowReaper.exe`	`field:"Image" kind:ends_with value:"\HollowReaper.exe"`