Cisco NVM - Webserver Download From File Sharing Website
This analytic detects unexpected outbound network connections initiated by known webserver processes such as `httpd.exe`, `nginx.exe`, or `tomcat.exe` to common file sharing or public content hosting services like…
Description
This analytic detects unexpected outbound network connections initiated by known webserver processes such as `httpd.exe`, `nginx.exe`, or `tomcat.exe` to common file sharing or public content hosting services like GitHub, Discord CDN, Transfer.sh, or Pastebin. Webservers are rarely expected to perform outbound downloads, especially to dynamic or anonymous file hosting domains. This behavior is often associated with server compromise, where an attacker uses a reverse shell, webshell, or injected task to fetch malware or tools post-exploitation. The detection leverages Cisco Network Visibility Module flow data, enriched with process context, to identify this highly suspicious behavior.
Detection logic
Detection requirements
- Platform
- ContainersESXiIaaSLinuxmacOSNetwork DevicesWindows
The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.
- Log source category
- cisco_network_visibility_module_flow_data
Known benign triggers
- In rare cases, a web server may make outbound connections to pull content for legitimate purposes (e.g., downloading templates or updates from a trusted source). However, communication to anonymous file-sharing or temporary content domains is strongly suspicious. If legitimate use is confirmed, domain- or process-level allowlisting is recommended.
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 |
|---|---|
| research.splunk.com/endpoint/4e8391eb-527e-4e39-9a17-c5bde2f89158/ | Only this detection cites it |
| www.cisa.gov/news-events/alerts/2023/04/13/cisa-adds-3-known-exploited-vulnerabilities-kev-catalog | Only this detection cites it |
| www.microsoft.com/en-us/security/blog/2024/01/17/new-ttps-observed-in-mint-sandstorm-campaign-targeting-high-profile-individuals-at-universities-and-research-orgs/ | 10from 2 sources |
From the source
- At source
- Open at source
- Upstream identifier
- 1984f997-3b49-4d4b-a7e9-dc5dbf88370e
- Tagged by the source as
- Cisco Network Visibility Module AnalyticsGhostRedirector IIS Module and Rungan BackdoorEndpointendpointSplunk 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