CWE-130: Improper Handling of Length Parameter Inconsistency
Description
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Submission Date :
July 19, 2006, midnight
Modification Date :
2023-06-29 00:00:00+00:00
Organization :
MITRE
Extended Description
If an attacker can manipulate the length parameter associated with an input such that it is inconsistent with the actual length of the input, this can be leveraged to cause the target application to behave in unexpected, and possibly, malicious ways. One of the possible motives for doing so is to pass in arbitrarily large input to the application. Another possible motivation is the modification of application state by including invalid data for subsequent properties of the application. Such weaknesses commonly lead to attacks such as buffer overflows and execution of arbitrary code.
Example - 1
In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing. However, the message length variable from the structure is used as the condition for ending the for loop without validating that the message length variable accurately reflects the length of the message body (CWE-606). This can result in a buffer over-read (CWE-125) by reading from memory beyond the bounds of the buffer if the message length variable indicates a length that is longer than the size of a message body (CWE-130).
// // get message from socket and store into buffer//
// //Ignoring possibliity that buffer > BUFFER_SIZE//
// // place contents of the buffer into message structure//
// // copy message body into string for processing//
message[index] = msg->msgBody[index];
// // process message//
ExMessage *msg = recastBuffer(buffer);int index;for (index = 0; index < msg->msgLength; index++) {}message[index] = '\0';success = processMessage(message);
int success;char buffer[BUFFER_SIZE];char message[MESSAGE_SIZE];if (getMessage(socket, buffer, BUFFER_SIZE) > 0) {}return success;int processMessageFromSocket(int socket) {}
Related Weaknesses
This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined to give an overview of the different insight to similar items that may exist at higher and lower levels of abstraction.
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