CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

阶段: Architecture and Design

策略: Libraries or Frameworks

阶段: Implementation Architecture and Design

阶段: Architecture and Design Implementation

策略: Attack Surface Reduction

描述: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

有效性: Limited

阶段: Architecture and Design

描述: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

阶段: Architecture and Design

策略: Parameterization

描述: If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.

阶段: Implementation

策略: Output Encoding

阶段: Implementation

描述: With Struts, write all data from form beans with the bean's filter attribute set to true.

阶段: Implementation

策略: Attack Surface Reduction

描述: To help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as more recent versions of Internet Explorer and Firefox), this attribute can prevent the user's session cookie from being accessible to malicious client-side scripts that use document.cookie. This is not a complete solution, since HttpOnly is not supported by all browsers. More importantly, XMLHTTPRequest and other powerful browser technologies provide read access to HTTP headers, including the Set-Cookie header in which the HttpOnly flag is set.

有效性: Defense in Depth

阶段: Implementation

策略: Input Validation

阶段: Architecture and Design

策略: Enforcement by Conversion

描述: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.

阶段: Operation

策略: Firewall

描述: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

有效性: Moderate

阶段: Operation Implementation

策略: Environment Hardening

描述: When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.