Windows Process Creation: Uncommon Child Processes Spawned by DefaultPack.EXE

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creation events where DefaultPack.EXE spawns a child process that is uncommon for that binary. Attackers may abuse signed or trusted Windows binaries to proxy execution and reduce the visibility of their real payload. The detection relies on Windows process creation telemetry, matching on the parent process path ending with \DefaultPack.exe.

Reporting behind it

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Windows Process Creation: Uncommon Child Processes Spawned by DefaultPack.EXE

Pivot detection · T1218 · 9 related

Changelog

v2

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-uncommon-child-process-spawned-by-defaultpack-exe-b2309017

title: "Windows Process Creation: Uncommon Child Processes Spawned by DefaultPack.EXE"
id: 25fc16d6-e015-453f-b614-72080b7d99f3
status: test
description: This rule flags process creation events where DefaultPack.EXE spawns a child process that is uncommon for that binary. Attackers may abuse signed or trusted Windows binaries to proxy execution and reduce the visibility of their real payload. The detection relies on Windows process creation telemetry, matching on the parent process path ending with \DefaultPack.exe.
references:
  - https://lolbas-project.github.io/lolbas/OtherMSBinaries/DefaultPack/
  - https://www.echotrail.io/insights/search/defaultpack.exe
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_defaultpack_uncommon_child_process.yml
author: frack113, Huntrule Team
date: 2022-12-31
modified: 2024-04-22
tags:
  - attack.stealth
  - attack.t1218
  - attack.execution
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith: \DefaultPack.exe
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: b2309017-4235-44fe-b5af-b15363011957
    type: derived

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