Sigma rule: File Download Via Nscurl - MacOS

Rule

Title

File Download Via Nscurl - MacOS

Status

test

Level

medium

Author

Daniel Cortez

Date

2024-06-04

File

rules/macos/process_creation/proc_creation_macos_nscurl_usage.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the execution of the nscurl utility in order to download files.

Log source

product

macos

category

process_creation

Detection

selection:
    Image|endswith: '/nscurl'
    CommandLine|contains:
        - '--download '
        - '--download-directory '
        - '--output '
        - '-dir '
        - '-dl '
        - '-ld'
        - '-o '
condition: selection

False positives (as the rule lists them)

• Legitimate usage of nscurl by administrators and users.

Tags

• attack.command-and-control
• attack.t1105

MITRE ATT&CK ids this rule names

• T1105

References

• https://www.loobins.io/binaries/nscurl/
• https://www.agnosticdev.com/content/how-diagnose-app-transport-security-issues-using-nscurl-and-openssl
• https://gist.github.com/nasbench/ca6ef95db04ae04ffd1e0b1ce709cadd

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/macos/process_creation/proc_creation_macos_nscurl_usage.yml