CWE-642: External Control of Critical State Data

Class Draft Simple

CWE版本: 4.18

更新日期: 2025-09-09

弱点描述

The product stores security-critical state information about its users, or the product itself, in a location that is accessible to unauthorized actors.

常见后果

影响范围: Access Control

技术影响: Bypass Protection Mechanism Gain Privileges or Assume Identity

说明: An attacker could potentially modify the state in malicious ways. If the state is related to the privileges or level of authentication that the user has, then state modification might allow the user to bypass authentication or elevate privileges.

影响范围: Confidentiality

技术影响: Read Application Data

说明: The state variables may contain sensitive information that should not be known by the client.

影响范围: Availability

技术影响: DoS: Crash, Exit, or Restart

说明: By modifying state variables, the attacker could violate the application's expectations for the contents of the state, leading to a denial of service due to an unexpected error condition.

潜在缓解措施

阶段: Architecture and Design

描述: Understand all the potential locations that are accessible to attackers. For example, some programmers assume that cookies and hidden form fields cannot be modified by an attacker, or they may not consider that environment variables can be modified before a privileged program is invoked.

阶段: Architecture and Design

策略: Attack Surface Reduction

阶段: Architecture and Design

描述: Store state information on the server side only. Ensure that the system definitively and unambiguously keeps track of its own state and user state and has rules defined for legitimate state transitions. Do not allow any application user to affect state directly in any way other than through legitimate actions leading to state transitions.

阶段: Architecture and Design

策略: Libraries or Frameworks

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: 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.

阶段: Testing

描述: Use automated static analysis tools that target this type of weakness. Many modern techniques use data flow analysis to minimize the number of false positives. This is not a perfect solution, since 100% accuracy and coverage are not feasible.

阶段: Testing

描述: Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

阶段: Testing

描述: Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

检测方法

方法: Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

有效性: High