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Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability
CVSS 3.1 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
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.
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return success;// get message from socket and store into buffer//Ignoring possibliity that buffer > BUFFER_SIZE
success = processMessage(message);// place contents of the buffer into message structure// copy message body into string for processingmessage[index] = msg->msgBody[index];// process messageHowever, 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 message body. This can result in a buffer over read 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).
The following C/C++ example demonstrates a buffer over-read due to a missing NULL terminator. The main method of a pattern matching utility that looks for a specific pattern within a specific file uses the string strncopy() method to copy the command line user input file name and pattern to the Filename and Pattern character arrays respectively.
}Scan_File(Filename, Pattern);/* Validate number of parameters and ensure valid content *//* copy filename parameter to variable, may cause off-by-one overflow *//* copy pattern parameter to variable, may cause off-by-one overflow */However, the code do not take into account that strncpy() will not add a NULL terminator when the source buffer is equal in length of longer than that provide size attribute. Therefore if a user enters a filename or pattern that are the same size as (or larger than) their respective character arrays, a NULL terminator will not be added (CWE-170) which leads to the printf() read beyond the expected end of the Filename and Pattern buffers.
To fix this problem, be sure to subtract 1 from the sizeof() call to allow room for the null byte to be added.
Pattern[31]='\0';strncpy(Pattern, argv[3], sizeof(Pattern)-1);/* copy filename parameter to variable, no off-by-one overflow *//* copy pattern parameter to variable, no off-by-one overflow */ExploitPedia is constantly evolving. Sign up to receive a notification when we release additional functionality.
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