COMMON WEAKNESS ENUMERATIONIncomplete

CWE-463

Deletion of Data Structure Sentinel

The accidental deletion of a data-structure sentinel can cause serious programming logic problems.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The accidental deletion of a data-structure sentinel can cause serious programming logic problems.

Extended description

Often times data-structure sentinels are used to mark structure of the data structure. A common example of this is the null character at the end of strings. Another common example is linked lists which may contain a sentinel to mark the end of the list. It is dangerous to allow this type of control data to be easily accessible. Therefore, it is important to protect from the deletion or modification outside of some wrapper interface which provides safety.

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

Other

Affected security scopes: Availability, Other

Generally this error will cause the data structure to not work properly.
Other

Affected security scopes: Authorization, Other

If a control character, such as NULL is removed, one may cause resource access control problems.

Defence

How is it prevented and fixed?

Architecture and Design

Architecture and design approach

Detail
Use an abstraction library to abstract away risky APIs. Not a complete solution.

Build and Compilation

Compilation or Build Hardening

Detail
Run or compile the software using features or extensions that automatically provide a protection mechanism that mitigates or eliminates buffer overflows. For example, certain compilers and extensions provide automatic buffer overflow detection mechanisms that are built into the compiled code. Examples include the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice.

Effectiveness: Defense in Depth

This is not necessarily a complete solution, since these mechanisms can only detect certain types of overflows. In addition, an attack could still cause a denial of service, since the typical response is to exit the application.

Operation

Operational defence

Detail
Use OS-level preventative functionality. Not a complete solution.