What is Concurrent Execution using Shared (CWE-362)?

TL;DR: Race conditions (CWE-362) occur due to improper synchronization in multithreaded applications, leading to data corruption or unauthorized access. Fix by using thread-safe constructs.

What is Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)?

Concurrent Execution using Shared Resource with Improper Synchronization (‘Race Condition’) (CWE-362) is a type of concurrency vulnerability that occurs when multiple threads access shared resources without proper synchronization. As defined by the MITRE Corporation under CWE-362, and classified by the OWASP Foundation under A06:2025 - Insecure Design…

Quick Summary

A race condition (CWE-362) is a concurrency issue where multiple threads or processes access shared resources without proper synchronization. This can lead to unexpected behavior such as data corruption, crashes, or unauthorized access. It matters because attackers can exploit these timing windows to manipulate critical operations.

Jump to: Quick Summary · Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Overview · How Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Works · Business Impact of Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) · Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Attack Scenario · How to Detect Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) · How to Fix Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) · Framework-Specific Fixes for Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) · How to Ask AI to Check Your Code for Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) · Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Best Practices Checklist · Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) FAQ · Vulnerabilities Related to Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) · References · Scan Your Own Site

Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Overview

What

A race condition is a concurrency issue where multiple threads or processes access shared resources without proper synchronization.

Why it matters

Improper synchronization can lead to data corruption, crashes, unauthorized access, and other security issues.

Where it occurs

In multithreaded applications that use shared resources without adequate synchronization mechanisms.

Who is affected

Developers working on multithreaded systems with insufficient synchronization.

Who is NOT affected

Applications using thread-safe constructs or minimizing shared state.

How Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Works

Root Cause

Multiple threads access a shared resource without proper synchronization, leading to unexpected behavior.

Attack Flow

1. An attacker identifies a race condition.
2. Exploits the timing window to manipulate critical operations.
3. Causes data corruption or unauthorized actions.

Prerequisites to Exploit

• Multithreaded application with shared resources.
• Lack of proper synchronization mechanisms.

Vulnerable Code

public class Counter {
    private int count = 0;

    public void increment() {
        count++;
    }
}

This code increments a counter without any synchronization, leading to race conditions if accessed concurrently by multiple threads.

Secure Code

import java.util.concurrent.atomic.AtomicInteger;

public class Counter {
    private AtomicInteger count = new AtomicInteger(0);

    public void increment() {
        count.incrementAndGet();
    }
}

Using AtomicInteger ensures that the counter is incremented atomically, preventing race conditions.

Business Impact of Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Availability

• DoS: Resource Consumption (CPU)
  • Can lead to resource exhaustion.
• DoS: Crash, Exit, or Restart
  • May cause crashes due to unexpected states.

Confidentiality

• Read Files or Directories
  • Allows unauthorized access to sensitive data.

Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Attack Scenario

1. Attacker identifies a race condition in a multithreaded application.
2. Exploits the timing window to manipulate critical operations.
3. Causes data corruption or unauthorized actions, leading to security breaches.

How to Detect Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Manual Testing

• Review code for shared resources accessed by multiple threads without proper synchronization.
• Check for lack of thread-safe constructs like synchronized blocks or atomic operations.

Automated Scanners (SAST/DAST)

Static analysis can detect missing synchronization, while dynamic testing identifies race conditions during runtime.

PenScan Detection

PenScan uses ZAP and other tools to identify potential race conditions in your codebase.

False Positive Guidance

A false positive occurs when a pattern looks risky but is actually safe due to context not visible to the scanner.

How to Fix Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

• Use synchronization primitives like synchronized blocks or locks.
• Minimize shared state and use thread-safe constructs.
• Ensure atomic operations on critical sections of code.

Framework-Specific Fixes for Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Java

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class Counter {
    private int count = 0;
    private final Lock lock = new ReentrantLock();

    public void increment() {
        lock.lock();
        try {
            count++;
        } finally {
            lock.unlock();
        }
    }
}

Using a ReentrantLock ensures that the counter is incremented safely.

How to Ask AI to Check Your Code for Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Review the following Java code block for potential CWE-362 vulnerabilities and rewrite it using thread-safe constructs:

public class Counter {
    private int count = 0;

    public void increment() {
        count++;
    }
}

Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) Best Practices Checklist

✅ Use synchronization primitives like synchronized blocks or locks. ✅ Minimize shared state and use thread-safe constructs. ✅ Ensure atomic operations on critical sections of code.

Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition) FAQ

How does a race condition occur?

A race condition occurs when multiple threads access shared resources without proper synchronization, leading to unexpected behavior or data corruption.

Can you provide an example of vulnerable code for CWE-362?

Vulnerable code often includes operations on shared variables that are not properly synchronized, such as incrementing a counter without using atomic operations.

What is the impact of a race condition in terms of confidentiality and integrity?

A race condition can lead to data corruption or unauthorized access if an attacker exploits timing windows to modify or read sensitive information.

How do you detect race conditions manually?

Manually detecting race conditions involves reviewing code for shared resources accessed by multiple threads without proper synchronization mechanisms like mutexes or semaphores.

What is the primary fix technique for preventing CWE-362?

The primary fix is to use thread-safe constructs such as synchronized blocks, locks, or atomic operations on shared variables.

How does PenScan detect race conditions?

PenScan uses static analysis and dynamic testing techniques to identify potential race conditions in your codebase.

What are the best practices for avoiding race conditions in multithreaded applications?

Best practices include minimizing shared state, using thread-safe constructs, and thoroughly testing concurrent access scenarios.

Vulnerabilities Related to Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

References

• MITRE - CWE-362
• OWASP Top 10:2025 A06 - Insecure Design
• CAPEC-26
• CAPEC-29
• NVD

Scan Your Own Site

Manual code review catches what you know to look for. An automated scan catches what you didn’t. Scan your own website using PenScan to find race conditions and other risks before an attacker does.