However in the case of Silverlight, it will only work if the crossdomain. For more granular control with Silverlight, clientaccesspolicy.
To test for RIA policy file weakness the tester should try to retrieve the policy files crossdomain. After retrieving all the policy files, the permissions allowed should be be checked under the least privilege principle.
Requests should only come from the domains, ports, or protocols that are necessary. Overly permissive policies should be avoided. Watch Star. Though this policy file does not allow data access for this domain, it defined a meta-policy that allows other policy files within this domain to determine how access will be handled.
A client will need to load a policy file other than the master for permissions related to this domain. This defines a meta-policy that only allows this master policy file to function for this domain.
It allows access to data on example. The allow-access-from element grants another domain access to read data from the current domain.
Clients may choose to handle cross-domain data differently depending on the format of that data. For text, or other non-visual data, a policy file may be used to determine if the client is allowed to load the data from the remote domain. Alternatively, some data, such as images or other visual data, may be loaded from a remote domain without permission from a policy file as long as the information specific to that data never reaches the source content. Should that content request information about the remote data, the policy file would then be checked to allow or disallow that action.
Note: An allow-access-from element in a non- master policy file can only grant another domain access to data within the directory in which it is defined and that directory's subdirectories. This policy file demonstrates the most permissive use of allow-access-from granting any other domain access to the files on this domain, even if an HTTP source is accessing data on this domain through HTTPS.
Here, the policy file allows access to example. This example is of a socket policy file. This XML should be served to a client through a socket connection when requested with policy-file-request.
It permits access to content from example. The allow-http-request-headers-from element grants a client hosting content from another domain to send user-defined headers to the current domain. Whereas the allow-access-from element grants permission to pull data from the current domain, this tag grants permission to push data - data in the form of headers. Note: An allow-http-request-headers-from element in a non- master policy file can only allow headers to be sent to pages within the directory in which the policy file is defined and that directory's subdirectories.
This policy file allows the Authorization header and any header beginning with the characters X-Foo from www. If a request is coming from foo. The policy-file-request element is not specific to policy file documents. Rather, policy-file-request is the root element of a single-node XML document used by a client to request policy file information from a socket server.
Upon reception of this document, a socket server should provide the client with the necessary policy file so that the client can continue with the connection or close it if the policy file does not permit it.
A socket connection receiving this data should respond with a policy file. That policy file definition then determines if the connection is allowed. This is the same content type the by-content-type value of the permitted-cross-domain-policies attribute uses to determine validity of a policy file. Instead of relying entirely on master policy files for meta-policies, clients may also decide to check for a X-Permitted-Cross-Domain-Policies header in documents to specify a meta-policy.
In addition to the values acceptable in permitted-cross-domain-policies , this header may also use a value of none-this-response to indicate that the current document should not be used as a policy file despite other headers or its content. Master policy files are policy files located in root of a domain with the file name crossdomain.
When clients require a policy file, this is the default location for the policy file they should check. A domain should always host a master policy file to enforce the its intended meta-policy. If a client is instructed to load a policy file other than the master policy file, the master policy file will still need to be checked by the client to ensure the meta-policy defined by the master policy file via the site-control element permits the use of the originally requested policy file.
Without a master policy file, it is left to the client to enforce the default behavior. Non-master policy files can only grant access to data within their own directory or within that directory's subdirectories. The following rules are used in determining if a value in the domain attribute of the allow-access-from or allow-http-request-headers-from elements matches an actual domain name:.
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