Cisco NVM - Curl Execution With Insecure Flags
This analytic detects the use of `curl.exe` with insecure flags such as `-k`, `--insecure`, `--proxy-insecure`, or `--doh-insecure` which disable TLS certificate validation. It leverages Cisco Network Visibility…
Description
This analytic detects the use of `curl.exe` with insecure flags such as `-k`, `--insecure`, `--proxy-insecure`, or `--doh-insecure` which disable TLS certificate validation. It leverages Cisco Network Visibility Module (NVM) flow data and process arguments to identify outbound connections initiated by curl where TLS checks were explicitly disabled. This behavior may indicate an attempt to bypass certificate validation to connect to potentially untrusted or malicious endpoints, a common tactic in red team operations, malware staging, or data exfiltration over HTTPS.
Detection logic
Detection requirements
- Platform
- Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- cisco_network_visibility_module_flow_data
Known benign triggers
- Usage of these flags to reach public IPs or uncommon destinations should be reviewed. Tuning may be required for domains with known certificate issues.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| thedfirreport.com/2025/05/19/another-confluence-bites-the-dust-falling-to-elpaco-team-ransomware/ | 2from 2 sources |
From the source
- At source
- Open at source
- Upstream identifier
- cc695238-3117-4e60-aa83-4beac2a42c69
- Tagged by the source as
- Cisco Network Visibility Module AnalyticsMicrosoft WSUS CVE-2025-59287PromptLockEndpointendpointSplunk CloudSplunk EnterpriseSplunk Enterprise Securityendpoint
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Oct 6, 2026
- Version
- 2