CWE-131: Incorrect Calculation of Buffer Size

阶段: Implementation

描述: When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts "&" characters to "&" for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input buffer.

阶段: Implementation

阶段: Implementation

策略: Input Validation

描述: Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.

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: Implementation

描述: When processing structured incoming data containing a size field followed by raw data, identify and resolve any inconsistencies between the size field and the actual size of the data (CWE-130).

阶段: Implementation

描述: When allocating memory that uses sentinels to mark the end of a data structure - such as NUL bytes in strings - make sure you also include the sentinel in your calculation of the total amount of memory that must be allocated.

阶段: Implementation

描述: Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.

有效性: Moderate

阶段: Implementation

描述: Use sizeof() on the appropriate data type to avoid CWE-467.

阶段: Implementation

描述: Use the appropriate type for the desired action. For example, in C/C++, only use unsigned types for values that could never be negative, such as height, width, or other numbers related to quantity. This will simplify validation and will reduce surprises related to unexpected casting.

阶段: Architecture and Design

策略: Libraries or Frameworks

阶段: Operation Build and Compilation

策略: Environment Hardening

有效性: Defense in Depth

阶段: Operation Build and Compilation

策略: Environment Hardening

有效性: Defense in Depth

阶段: Operation

策略: Environment Hardening

有效性: Defense in Depth

阶段: Implementation

策略: Compilation or Build Hardening

描述: Examine compiler warnings closely and eliminate problems with potential security implications, such as signed / unsigned mismatch in memory operations, or use of uninitialized variables. Even if the weakness is rarely exploitable, a single failure may lead to the compromise of the entire system.

阶段: Architecture and Design Operation

策略: Environment Hardening

描述: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

阶段: Architecture and Design Operation

策略: Sandbox or Jail

有效性: Limited