Description
Release 9.4.37 introduced a more precise implementation of RFC3986 with regards to URI decoding, together with some new compliance modes to optionally allow support of some URI that may have ambiguous interpretation within the Servlet specified API methods behaviours. The default mode allowed % encoded . characters to be excluded for URI normalisation, which is correct by the RFC, but is not assumed by common Servlet implementations.
Impact
The default compliance mode allows requests with URIs that contain %2e or %2e%2e segments to access protected resources within the WEB-INF directory. For example a request to /context/%2e/WEB-INF/web.xml can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Workarounds
The HttpCompliance mode RFC7230_NO_AMBIGUOUS_URIS can be enabled by updating start.d/http.ini to include:
jetty.http.compliance=RFC7230_NO_AMBIGUOUS_URIS
charlesk40 Analyst
Description
Release 9.4.37 introduced a more precise implementation of RFC3986 with regards to URI decoding, together with some new compliance modes to optionally allow support of some URI that may have ambiguous interpretation within the Servlet specified API methods behaviours. The default mode allowed % encoded . characters to be excluded for URI normalisation, which is correct by the RFC, but is not assumed by common Servlet implementations.
Impact
The default compliance mode allows requests with URIs that contain
%2eor%2e%2esegments to access protected resources within theWEB-INFdirectory. For example a request to/context/%2e/WEB-INF/web.xmlcan retrieve theweb.xmlfile. This can reveal sensitive information regarding the implementation of a web application.Workarounds
The HttpCompliance mode RFC7230_NO_AMBIGUOUS_URIS can be enabled by updating
start.d/http.inito include: