Cisco Secure Firewall - Wget or Curl Download
The following analytic detects outbound connections initiated by command-line tools such as curl or wget. It leverages Cisco Secure Firewall Threat Defense logs and identifies allowed connections (action=Allow) where…
Description
The following analytic detects outbound connections initiated by command-line tools such as curl or wget. It leverages Cisco Secure Firewall Threat Defense logs and identifies allowed connections (action=Allow) where either the EVE_Process or ClientApplication fields indicate use of these utilities. While curl and wget are legitimate tools commonly used for software updates and scripting, adversaries often abuse them to download payloads, retrieve additional tools, or establish staging infrastructure from compromised systems. If confirmed malicious, this behavior may indicate the download phase of an attack chain or a command-and-control utility retrieval.
Detection logic
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows
The rule states no platform. This is derived from the 4 ATT&CK techniques it maps to.
- Log source category
- cisco_secure_firewall_threat_defense_connection_event
Known benign triggers
- Developers, administrators, or automation tools may use `curl` or `wget` for legitimate purposes such as software installation, configuration scripts, or CI/CD tasks. Security tools or health monitoring scripts may also use these utilities to check service availability or download updates. Review the destination `url`, frequency, and process context to validate whether the download activity is authorized.
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 |
|---|---|
| www.cisco.com/c/en/us/td/docs/security/firepower/741/api/FQE/secure_firewall_estreamer_fqe_guide_740.pdf | 18 |
From the source
- At source
- Open at source
- Upstream identifier
- 173a1cb9-1814-4128-a9dc-f29dade89957
- Tagged by the source as
- Cisco Secure Firewall Threat Defense AnalyticsNetworknetworkSplunk CloudSplunk EnterpriseSplunk Enterprise Securitynetwork
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1