CVE-2023-43795: WPS Server Side Request Forgery vulnerability

Summary

The OGC Web Processing Service (WPS) specification is designed to process information from any server using GET and POST requests.

This presents the opportunity for Server Side Request Forgery.

Details

This vulnerability requires:

• The WPS extension to be installed
• The WPS security setting “Disable complex inputs” to be unselected
• Security URL checks to be disabled

Impact

This vulnerability presents the opportunity for Server Side Request Forgery.

Mitigation

The ability to reference an external URL location is defined by the WPS standard Execute operation. This operations is defined by an Industry and International standard and cannot be redefined by the GeoServer application in isolation.

To disable complex remote inputs on GeoServer 2.20.5 and GeoServer 2.21.0:

1. Navigate to Security > WPS Security page
2. Locate Complex Inputs heading
3. Select the check box for Disable loading complex inputs from remote references

Resolution

To allow processing of complex inputs safely in GeoServer 2.22.5 and GeoServer 2.23.2:

1. Navigate to Security > URL Checks
2. Enable URL Checks are enabled setting
3. Check the user manual for examples of how to trust specific locations for your external services.

Processing of complex inputs safely is on by default in GeoServer 2.24.0.

References

• Complex Inputs
• URL Checks