GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. The GeoServer security mechanism can perform an unchecked JNDI lookup, which in turn can be used to perform class deserialization and result in arbitrary code execution. The same can happen while configuring data stores with data sources located in JNDI, or while setting up the disk quota mechanism. In order to perform any of the above changes, the attack needs to have obtained admin rights and use either the GeoServer GUI, or its REST API. The lookups are going to be restricted in GeoServer 2.21.0, 2.20.4, 1.19.6. Users unable to upgrade should restrict access to the geoserver/web and geoserver/rest via a firewall and ensure that the GeoWebCache is not remotely accessible.
GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. GeoServer includes support for the OGC Filter expression language and the OGC Common Query Language (CQL) as part of the Web Feature Service (WFS) and Web Map Service (WMS) protocols. CQL is also supported through the Web Coverage Service (WCS) protocol for ImageMosaic coverages. Users are advised to upgrade to either version 2.21.4, or version 2.22.2 to resolve this issue. Users unable to upgrade should disable the PostGIS Datastore encode functions setting to mitigate strEndsWith, strStartsWith and PropertyIsLike misuse and enable the PostGIS DataStore preparedStatements setting to mitigate the FeatureId misuse.
GeoServer through 2.18.5 and 2.19.x through 2.19.2 allows SSRF via the option for setting a proxy host.
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
Summary
The WMS specification defines an sld=<url> parameter for GetMap, GetLegendGraphic and GetFeatureInfo operations for user supplied "dynamic styling". Enabling the use of dynamic styles, without also configuring URL checks, provides the opportunity for Service Side Request Forgery. It is possible to use this for "Blind SSRF" on the WMS endpoint to steal NetNTLMv2 hashes via file requests to malicious servers.
Details
This vulnerability requires:
WMS Settings dynamic styling being enabled Security URL checks to be disabled, or to be enabled and allowing file:\\ access
Impact
This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access.
Mitigation
The ability to reference an external URL location is defined by the WMS standard GetMap, GetFeatureInfo and GetLegendGraphic operations. These operations are defined by an Industry and International standard and cannot be redefined by the GeoServer application in isolation.
To disable dynamic styling on GeoServer 2.10.3 and GeoServer 2.11.1:
1. Navigate to Services > WMS Settings page 2. Locate Dynamic styling heading 3. Select the Disable usage of SLD and SLDBODY parameters in GET requests and user styles in POST checkbox.
Resolution
To allow dynamic styling safely on 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: ^https://styles\.server\.net/cartography/.$ 4. Enable dynamic styling on the Services > WMS Settings page, deselect the Disable usage of SLD and SLDBODY parameters in GET requests and user styles in POST checkbox.
Use of dynamic styling safely is on by default in GeoServer 2.24.0.
References
Disabling usage of dynamic styling in GetMap, GetFeatureInfo and GetLegendGraphic requests URL Checks