What is Use of getlogin() in Multithreaded (CWE-558)?

TL;DR: Use of getlogin() in multithreaded applications (CWE-558) can lead to incorrect user information, compromising security. Fix it by using the thread-safe alternative getlogin_r().

What is Use of getlogin() in Multithreaded Application?

Use of getlogin() in multithreaded application (CWE-558) is a type of concurrency issue that occurs when the non-reentrant function getlogin() is used in a multithreaded context, potentially causing it to return incorrect values. As defined by the MITRE Corporation under CWE-558, and classified by the OWASP Foundation as not directly mapped.

Quick Summary

Use of getlogin() in multithreaded applications can lead to security vulnerabilities such as unauthorized access and data integrity issues due to inconsistent user information returned from concurrent calls. This vulnerability affects multithreaded applications that rely on accurate user identity verification, compromising their ability to enforce proper access control mechanisms.

Jump to: Quick Summary · Use of getlogin() in Multithreaded Application Overview · How Use of getlogin() in Multithreaded Application Works · Business Impact of Use of getlogin() in Multithreaded Application · Use of getlogin() in Multithreaded Application Attack Scenario · How to Detect Use of getlogin() in Multithreaded Application · How to Fix Use of getlogin() in Multithreaded Application · Framework-Specific Fixes for Use of getlogin() in Multithreaded Application · How to Ask AI to Check Your Code for Use of getlogin() in Multithreaded Application · Use of getlogin() in Multithreaded Application Best Practices Checklist · Use of getlogin() in Multithreaded Application FAQ · Vulnerabilities Related to Use of getlogin() in Multithreaded Application · References · Scan Your Own Site

Use of getlogin() in Multithreaded Application Overview

What: The use of the non-reentrant function getlogin() in multithreaded applications.

Why it matters: Incorrect user information can lead to security vulnerabilities such as unauthorized access and data integrity issues. This affects multithreaded applications that rely on accurate user identity verification for proper access control mechanisms.

Where it occurs: In multithreaded environments where getlogin() is called concurrently without proper synchronization or thread-safe alternatives.

Who is affected: Applications that use getlogin() in a concurrent context, such as multithreaded servers and applications with multiple threads accessing shared resources.

Who is NOT affected: Single-threaded applications or those using reentrant functions like getlogin_r() instead of getlogin().

How Use of getlogin() in Multithreaded Application Works

Root Cause

The root cause lies in the non-reentrant nature of the getlogin() function, which is not designed to be thread-safe. When used concurrently, it can return incorrect values due to race conditions and inconsistent state management.

Attack Flow

1. An attacker initiates multiple threads that call getlogin().
2. Due to concurrent execution, getlogin() may return incorrect user information.
3. This leads to security vulnerabilities such as unauthorized access or data integrity issues.

Prerequisites to Exploit

• The application must use getlogin() in a multithreaded context without proper synchronization mechanisms.
• Concurrent calls to getlogin() must be possible, leading to race conditions and inconsistent results.

Vulnerable Code

#include <unistd.h>

void getUserInfo() {
    char *user = getlogin();
    printf("User: %s\n", user);
}

This code demonstrates the use of getlogin() in a multithreaded context, which can lead to incorrect values due to concurrent execution.

Secure Code

#include <unistd.h>
#include <stdio.h>

void getUserInfo() {
    char *user = getlogin_r(NULL, 0);
    printf("User: %s\n", user);
}

The secure version uses getlogin_r() instead of getlogin(), ensuring correct values even in concurrent execution environments.

Business Impact of Use of getlogin() in Multithreaded Application

Confidentiality

Incorrect user information can lead to unauthorized access and data exposure, compromising the confidentiality of sensitive data.

Integrity

Data integrity issues may arise due to incorrect user identity verification, leading to unintended modifications or tampering with application data.

Use of getlogin() in Multithreaded Application Attack Scenario

1. An attacker initiates multiple threads that call getlogin() concurrently.
2. Due to the non-reentrant nature of getlogin(), it returns inconsistent values across threads.
3. This leads to security vulnerabilities such as unauthorized access or data integrity issues.

How to Detect Use of getlogin() in Multithreaded Application

Manual Testing

• Review code for calls to getlogin() within multithreaded contexts.
• Ensure proper synchronization mechanisms are in place or use thread-safe alternatives like getlogin_r().

Automated Scanners (SAST / DAST)

Static analysis can detect direct calls to getlogin(), while dynamic testing may be required to verify concurrent execution scenarios and race conditions.

PenScan Detection

PenScan’s scanner engines such as ZAP, Nuclei, Wapiti, Nikto, SSLyze, Dalfox, and Nmap can identify potential issues related to the use of getlogin() in multithreaded applications.

False Positive Guidance

False positives may occur if getlogin_r() is used instead of getlogin(), as this function is designed for concurrent execution environments.

How to Fix Use of getlogin() in Multithreaded Application

• Replace non-reentrant functions like getlogin() with thread-safe alternatives such as getlogin_r().
• Ensure proper synchronization mechanisms are in place when using non-thread-safe functions in multithreaded contexts.

Framework-Specific Fixes for Use of getlogin() in Multithreaded Application

C/C++

#include <unistd.h>

void getUserInfo() {
    char *user = getlogin_r(NULL, 0);
    printf("User: %s\n", user);
}

This example demonstrates the use of getlogin_r() instead of getlogin() in a multithreaded context.

How to Ask AI to Check Your Code for Use of getlogin() in Multithreaded Application

Use of getlogin() in Multithreaded Application Best Practices Checklist

• ✅ Avoid using non-reentrant functions like getlogin() in multithreaded contexts.
• ✅ Replace getlogin() with the reentrant function getlogin_r() for concurrent execution environments.
• ✅ Ensure proper synchronization mechanisms are in place when using non-thread-safe functions.

Use of getlogin() in Multithreaded Application FAQ

How does the use of getlogin() in multithreaded applications lead to incorrect values?

The function getlogin() is not designed to be thread-safe, leading to potential race conditions and returning incorrect user information when used concurrently.

Why should I avoid using getlogin() in multithreaded environments?

Using getlogin() can result in inconsistent or incorrect data due to its non-reentrant nature, making it unreliable for security-critical operations.

What are the typical consequences of this vulnerability?

Incorrect values from getlogin() may lead to unauthorized access and integrity issues by bypassing protection mechanisms.

How can I detect Use of getlogin() in Multithreaded Application vulnerabilities?

Look for calls to getlogin() within multithreaded contexts and verify if they are properly synchronized or replaced with thread-safe alternatives like getlogin_r().

Can you provide an example of secure code that avoids this vulnerability?

Use getlogin_r() instead, which is reentrant and ensures correct values even in concurrent execution environments.

What are the best practices for preventing this issue in multithreaded applications?

Avoid using non-reentrant functions like getlogin(). Opt for thread-safe alternatives or ensure proper synchronization mechanisms are in place.

How can I ask an AI assistant to check my code for Use of getlogin() in Multithreaded Application vulnerabilities?

Review the following C++ code block for potential CWE-558 Use of getlogin() in Multithreaded Application vulnerabilities and rewrite it using thread-safe alternatives.

Vulnerabilities Related to Use of getlogin() in Multithreaded Application

References

• MITRE
• 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 Use of getlogin() in Multithreaded Application and other risks before an attacker does.