COMMON WEAKNESS ENUMERATIONDraft

CWE-123

Write-what-where Condition

Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

Soyutlama

Base

Yapı

Simple

Sömürü İhtimali

High

Problemi anla

Problem nedir?

Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

Kök neden

Problem nasıl ve ne zaman oluşur?

Yaşam döngüsü evresi

Implementation

Risk

Başarılı sömürü neye yol açar?

Modify MemoryExecute Unauthorized Code or CommandsGain Privileges or Assume IdentityDoS: Crash, Exit, or RestartBypass Protection Mechanism

Etkilenen güvenlik alanları: Integrity, Confidentiality, Availability, Access Control

Clearly, write-what-where conditions can be used to write data to areas of memory outside the scope of a policy. Also, they almost invariably can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can redirect a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.
DoS: Crash, Exit, or RestartModify Memory

Etkilenen güvenlik alanları: Integrity, Availability

Many memory accesses can lead to program termination, such as when writing to addresses that are invalid for the current process.
Bypass Protection MechanismOther

Etkilenen güvenlik alanları: Access Control, Other

When the consequence is arbitrary code execution, this can often be used to subvert any other security service.

Savunma

Nasıl önlenir ve çözülür?

Architecture and Design

Language Selection

Detay
Use a language that provides appropriate memory abstractions.

Operation

Operasyonel savunma

Detay
Use OS-level preventative functionality integrated after the fact. Not a complete solution.

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.