CAPEC-279 SOAP Manipulation

CAPEC ID: 279

CAPEC-279 Metadata

Likelihood of Attack

Medium

Typical Severity

High

Overview

Summary

Simple Object Access Protocol (SOAP) is used as a communication protocol between a client and server to invoke web services on the server. It is an XML-based protocol, and therefore suffers from many of the same shortcomings as other XML-based protocols. Adversaries can make use of these shortcomings and manipulate the content of SOAP paramters, leading to undesirable behavior on the server and allowing the adversary to carry out a number of further attacks.

Prerequisites

An application uses SOAP-based web service api. An application does not perform sufficient input validation to ensure that user-controllable data is safe for an XML parser. The targeted server either fails to verify that data in SOAP messages conforms to the appropriate XML schema, or it fails to correctly handle the complete range of data allowed by the schema.

Execution Flow

Step Phase Description Techniques
1 Exploit [Find target application] The adversary needs to identify an application that uses SOAP as a communication protocol.
  • Observe HTTP traffic to an application and look for SOAP headers.
2 Experiment [Detect Incorrect SOAP Parameter Handling] The adversary tampers with the SOAP message parameters and looks for indications that the tampering caused a change in behavior of the targeted application.
  • Send more data than would seem reasonable for a field and see if the server complains.
  • Send nonsense data in a field that expects a certain subset, such as product names or sequence numbers, and see if the server complains.
  • Send XML metacharacters as data and see how the server responds.
3 Exploit [Manipulate SOAP parameters] The adversary manipulates SOAP parameters in a way that causes undesirable behavior for the server. This can result in denial of service, information disclosure, arbitrary code exection, and more.
  • Create a recursive XML payload that will take up all of the memory on the server when parsed, resulting in a denial of service. This is known as the billion laughs attack.
  • Insert XML metacharacters into data fields that could cause the server to go into an error state when parsing. This could lead to a denial of service.
  • Insert a large amount of data into a field that should have a character limit, causing a buffer overflow.

Potential Solutions / Mitigations

No specific solutions listed.

Related Weaknesses (CWE)

CWE ID Description
CWE-707 Improper Neutralization

Related CAPECs

CAPEC ID Description
CAPEC-110 An attacker modifies the parameters of the SOAP message that is sent from the service consumer to the service provider to initiate a SQL injection attack. On the service provider side, the SOAP message is parsed and parameters are not properly validated before being used to access a database in a way that does not use parameter binding, thus enabling the attacker to control the structure of the executed SQL query. This pattern describes a SQL injection attack with the delivery mechanism being a SOAP message.
CAPEC-228 An attacker injects malicious content into an application's DTD in an attempt to produce a negative technical impact. DTDs are used to describe how XML documents are processed. Certain malformed DTDs (for example, those with excessive entity expansion as described in CAPEC 197) can cause the XML parsers that process the DTDs to consume excessive resources resulting in resource depletion.
CAPEC-278 An adversary manipulates a web service related protocol to cause a web application or service to react differently than intended. This can either be performed through the manipulation of call parameters to include unexpected values, or by changing the called function to one that should normally be restricted or limited. By leveraging this pattern of attack, the adversary is able to gain access to data or resources normally restricted, or to cause the application or service to crash.

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