CAPEC-528: XML Flood
Also known as: XML Denial of Service (XML DoS)
An adversary may execute a flooding attack using XML messages with the intent to deny legitimate users access to a web service. These attacks are accomplished by sending a large number of XML based requests and letting the service attempt to parse each one. In many cases this type of an attack will result in a XML Denial of Service (XDoS) due to an application becoming unstable, freezing, or crashing.
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Overview
XDoS is most closely associated with web services, SOAP, and Rest, because remote service requesters can post malicious XML payloads to the service provider designed to exhaust the service provider's memory, CPU, and/or disk space. The main weakness in XDoS is that the service provider generally must inspect, parse, and validate the XML messages to determine routing, workflow, security considerations, and so on. It is exactly these inspection, parsing, and validation routines that XDoS targets. This attack exploits the loosely coupled nature of web services, where the service provider has little to no control over the service requester and any messages the service requester sends.
How the attack works
The phases an attacker typically follows to carry out this attack.
- Step 1Explore
[Survey the target] Using a browser or an automated tool, an attacker records all instance of web services to process XML requests.
- Use an automated tool to record all instances of URLs to process XML requests.
- Use a browser to manually explore the website and analyze how the application processes XML requests.
- Step 2Experiment
An adversary crafts input data that may have an adverse effect on the operation of the web service when the XML data sent to the service.
- Step 3Exploit