In this post, we'll discuss a recently discovered vulnerability (CVE-2021-38737) in SEMCMS v1.1 that allows attackers to perform SQL injection attacks via the Ant_Pro.php file. We'll delve into the details of the exploit, some example code snippets, and link to original references. Finally, we'll provide some recommendations on how to mitigate the vulnerability and ensure the security of your application.
SEMCMS (http://www.semcms.com) is a simple and easy-to-use content management system (CMS) that allows users to build and manage websites without any technical knowledge. Unfortunately, the v1.1 version of the CMS has been found to be vulnerable to SQL injection attacks, which can allow attackers to extract sensitive data from the underlying database, potentially including sensitive user information, administrative passwords, and application secrets.
According to the official CVE database, CVE-2021-38737 (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38737) details this vulnerability. The vulnerability specifically targets the Ant_Pro.php file, allowing remote attackers to send crafted input that ultimately results in an SQL injection attack.
A quick analysis of the Ant_Pro.php file reveals that there are insufficient input validation and output escaping mechanisms for handling user-supplied data. As a consequence, an attacker can submit unsanitized input that will directly be embedded into SQL queries executed by the application, resulting in SQL injection attacks.
An attacker submits the following input for the 'id' parameter: 1'; DROP TABLE users; --
2. The application includes this value in an SQL query without verifying or sanitizing it: SELECT * FROM products WHERE id='1'; DROP TABLE users; --'
3. The SQL server executes the query, dropping the users table, and potentially causing data loss or other damaging consequences.
Here's a simple code snippet that illustrates the vulnerability
// In Ant_Pro.php // Retrieve user-supplied input $id = $_GET['id']; // Query the database with unsanitized input $sql = "SELECT * FROM products WHERE id='$id'"; $result = mysqli_query($conn, $sql);
To protect your application from this vulnerability, we recommend the following steps
1. Always validate user input - Make sure that any data supplied by users adheres to the expected format and contains no malicious payload. This can be accomplished by applying appropriate input validation techniques, such as regular expressions, white-listing allowed characters, or employing a validation library.
2. Employ prepared statements - Instead of directly including user-supplied data in SQL queries, use prepared statements to separate the data from the query structure. This helps ensure that user input won't be mistakenly interpreted as SQL commands. For example, with MySQLi:
// In Ant_Pro.php // Retrieve user-supplied input $id = $_GET['id']; // Prepare a statement with a placeholder for the id $stmt = $conn->prepare("SELECT * FROM products WHERE id=?"); // Bind the parameter and execute the statement $stmt->bind_param("i", $id); $stmt->execute(); // Fetch and process the result $result = $stmt->get_result();
3. Update to a more recent version of the CMS - Check the website of SEMCMS (http://www.semcms.com) for updates and patches that address this vulnerability. Alternatively, consider switching to a more secure and actively maintained CMS platform.
In this article, we've explored the details of the CVE-2021-38737 vulnerability, which affects SEMCMS v1.1 and allows attackers to perform SQL injections via the Ant_Pro.php file. By following the mitigation steps outlined above, application developers and administrators can help ensure their applications and user data remain secure and protected against this type of attack.
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Published on: 10/28/2022 15:15:00 UTC
Last modified on: 10/28/2022 18:34:00 UTC