The program obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.
An attacker can supply a pointer for memory locations that the program is not expecting. If the pointer is dereferenced for a write operation, the attack might allow modification of critical program state variables, cause a crash, or execute code. If the dereferencing operation is for a read, then the attack might allow reading of sensitive data, cause a crash, or set a program variable to an unexpected value (since the value will be read from an unexpected memory location).
There are several variants of this weakness, including but not necessarily limited to:
- The untrusted value is directly invoked as a function call.
- In OS kernels or drivers where there is a boundary between "userland" and privileged memory spaces, an untrusted pointer might enter through an API or system call.
- Inadvertently accepting the value from an untrusted control sphere when it did not have to be accepted as input at all. This might occur when the code was originally developed to be run by a single user in a non-networked environment, and the code is then ported to or otherwise exposed to a networked environment.
If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory. If the untrusted pointer references a memory location that is not accessible to the program, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly. If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
Latest vulnerabilities for CWE-822
Description of CWE-822 on Mitre website