Apartment Visitor Management System (AVMS) v1., a software application designed to handle visitor check-ins and track visitor records for residential complexes, has been reported with a significant security flaw. This vulnerability, logged as CVE-2022-44139, allows an attacker to execute SQL Injection attacks via the /avms/index.php interface. In this post, we will delve into the details of this vulnerability, provide a sample exploit, and offer mitigation strategies to address the issue.

Details of the vulnerability

The primary cause of the vulnerability is improper handling of user-supplied input data by the software, leading to potential SQL injection attacks. An attacker can take advantage of this vulnerability to compromise the application, exfiltrate sensitive user data, or execute arbitrary SQL queries against the backend database.

Researchers have identified that the vulnerability resides in the /avms/index.php file, where user input is not sufficiently sanitized. As a result, an attacker could craft a malicious SQL query, which, when executed, could result in unauthorized access to the application's database.

Exploit details

Suppose a malicious actor wants to exploit this vulnerability. In that case, they can submit specially crafted input data through the /avms/index.php interface containing SQL commands. These commands would then execute on the server, potentially leading to unauthorized database access or modification.

To exemplify a simple attack, consider the following SQL injection payload

' or '1'='1

By injecting this payload in a vulnerable field, a malicious user could retrieve all records from the visitors' table.

Example of vulnerable code snippet

The following code samples are hypothetical and represent a possible vulnerable implementation in the /avms/index.php file:

// Get user input
$username = $_POST['username'];
$password = $_POST['password'];

// Create SQL query
$sql = "SELECT * FROM users WHERE username='$username' AND password='$password'";

// Execute query and handle results
$result = mysqli_query($connection, $sql);

if (mysqli_num_rows($result) > ) {
    // User found, log in and redirect
} else {
    // User not found, display error message

In the example above, the user input is included in the SQL query without proper sanitization, leading to potential SQL injection attacks.

Mitigation strategies

To protect against this vulnerability, developers should implement the following best practices in their code:

1. Parameterized queries: Replace traditional SQL queries with parameterized queries, also known as prepared statements, which can effectively separate data from SQL syntax, mitigating the risks of SQL injection.

2. Input validation: Always validate the user input to ensure it conforms to the expected data type and format. This can prevent the introduction of malicious data into the application.

3. Least privilege principle: Limit the permissions granted to database accounts used in web applications by adhering to the least privilege principle. This restricts potential data exposure in the event of a security breach.


CVE-2022-44139 represents a severe security flaw in Apartment Visitor Management System v1.. By exploiting this issue, an attacker could gain unauthorized access to sensitive information or execute malicious SQL commands. Developers should immediately implement the recommended mitigation strategies to protect against this vulnerability. For more information about this specific CVE, refer to the original references provided below:

- CVE-2022-44139 - National Vulnerability Database
- Exploit Database - SQL Injection Vulnerability in AVMS v1.

Always stay aware of the latest security vulnerabilities and stay proactive in protecting your software applications from potential threats.


Published on: 11/23/2022 16:15:00 UTC
Last modified on: 11/26/2022 03:40:00 UTC