macOS: In-Memory Download and Compile via curl and osacompile in a Single Command

Alerts when macOS processes include both curl and osacompile, consistent with downloading and compiling payloads.

FreeReviewedSigma · Medium · v2

Product: macos
Category: process_creation
Author: Sohan G (D4rkCiph3r), Red Canary (idea) (SigmaHQ), DRL 1.1
Published: 2023-08-22
Updated: 2026-07-31

ATT&CK techniques

Execution → C2

Recon
Resource Dev
Initial Access
Execution
- T1059.007JavaScript
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule flags process creation on macOS where the command line contains both curl and osacompile, indicating a potential in-memory workflow that downloads and compiles payloads. Attackers may use this pattern to quickly assemble and execute malicious code without writing obvious artifacts to disk. The detection relies on process creation telemetry with command-line fields capturing both utilities in the same invocation.

Reporting behind it

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macOS: In-Memory Download and Compile via curl and osacompile in a Single Command

Pivot detection · T1105 · 9 related

Changelog

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.

macos-in-memory-download-and-compile-via-curl-and-osacompile-13db8d2e

title: "macOS: In-Memory Download and Compile via curl and osacompile in a Single Command"
id: 87320a26-9737-4f67-a4aa-98b8f113bea8
status: test
description: This rule flags process creation on macOS where the command line contains both curl and osacompile, indicating a potential in-memory workflow that downloads and compiles payloads. Attackers may use this pattern to quickly assemble and execute malicious code without writing obvious artifacts to disk. The detection relies on process creation telemetry with command-line fields capturing both utilities in the same invocation.
references:
  - https://redcanary.com/blog/mac-application-bundles/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/macos/process_creation/proc_creation_macos_susp_in_memory_download_and_compile.yml
author: Sohan G (D4rkCiph3r), Red Canary (idea), Huntrule Team
date: 2023-08-22
tags:
  - attack.command-and-control
  - attack.execution
  - attack.t1059.007
  - attack.t1105
logsource:
  category: process_creation
  product: macos
detection:
  selection:
    CommandLine|contains|all:
      - osacompile
      - curl
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 13db8d2e-7723-4c2c-93c1-a4d36994f7ef
    type: derived

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