Use of Expired File Descriptor

The product uses or accesses a file descriptor after it has been closed.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The product uses or accesses a file descriptor after it has been closed.

Extended description

After a file descriptor for a particular file or device has been released, it can be reused. The code might not write to the original file, since the reused file descriptor might reference a different file or device.

Terminology

Alternate terms and usages

Stale file descriptor

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

Read Files or Directories

Affected security scopes: Confidentiality

The program could read data from the wrong file.

DoS: Crash, Exit, or Restart

Affected security scopes: Availability

Accessing a file descriptor that has been closed can cause a crash.

Defence

How is it prevented and fixed?

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

Verification

How is it detected?

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.)