COMMON WEAKNESS ENUMERATIONIncomplete

CWE-823

Use of Out-of-range Pointer Offset

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.

Soyutlama

Base

Yapı

Simple

Sömürü İhtimali

Medium

Problemi anla

Problem nedir?

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.

Genişletilmiş açıklama

While a pointer can contain a reference to any arbitrary memory location, a program typically only intends to use the pointer to access limited portions of memory, such as contiguous memory used to access an individual array. Programs may use offsets in order to access fields or sub-elements stored within structured data. The offset might be out-of-range if it comes from an untrusted source, is the result of an incorrect calculation, or occurs because of another error. If an attacker can control or influence the offset so that it points outside of the intended boundaries of the structure, then the attacker may be able to read or write to memory locations that are used elsewhere in the product. As a result, the attack might change the state of the product as accessed through program variables, cause a crash or instable behavior, and possibly lead to code execution.

Terminoloji

Alternatif adlar ve kullanım biçimleri

Untrusted pointer offset

This term is narrower than the concept of "out-of-range" offset, since the offset might be the result of a calculation or other error that does not depend on any externally-supplied values.

Kök neden

Problem nasıl ve ne zaman oluşur?

Yaşam döngüsü evresi

Implementation

Risk

Başarılı sömürü neye yol açar?

Read Memory

Etkilenen güvenlik alanları: Confidentiality

If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.

DoS: Crash, Exit, or Restart

Etkilenen güvenlik alanları: Availability

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.

Execute Unauthorized Code or CommandsModify Memory

Etkilenen güvenlik alanları: Integrity, Confidentiality, Availability

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.

Savunma

Nasıl önlenir ve çözülür?

Follow secure coding guidelines for input handling and boundary checking.
Enforce strict security reviews and automated static analysis (SAST) checks.

Doğrulama

Nasıl tespit edilir?

Automated Static Analysis

High

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.)

Automated Dynamic Analysis

Moderate

Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++ [REF-1518].

Crafted inputs are necessary to reach the code containing the error, such as generated by fuzzers. Also, these tools may reduce performance, and they only report the error condition - not the original mistake that led to the error.