SQL Injection in API Endpoints – Client Case Study

For ages, SQL Injection has remained one of the most dangerous and widespread vulnerabilities across the entire field of cybersecurity, which is constantly changing. In a recent security audit, our test team uncovered an array of API endpoints that allow SQL injection attacks while exposing sensitive platforms to exploitation risk. This blog post will provide readers with an overview of the vulnerability, its effects, technical details, and recommended remediation techniques against harmful applications.

What is SQL Injection?

Injection of malicious SQL code in user-dependent input fields is a serious web application vulnerability that empowers hackers to modify backend SQL queries. It may lead to unauthorized access to sensitive data, and alteration of data.

Impact of SQL Injection

The consequences of SQL Injection vulnerabilities can be devastating, including:

1. Database Manipulation
   Attackers can modify or delete records, causing data loss, corruption, or inconsistency.

2. Unauthorized Data Access
   Sensitive information such as personal data, credentials, and system configurations can be exfiltrated.

3. Privilege Escalation
   By exploiting SQL Injection, attackers can escalate privileges, gaining administrative control over the application.

4. Complete Database Compromise
   In severe cases, attackers can gain full access to the database server, enabling data exfiltration, system shutdowns, or ransomware attacks.

Technical Findings

The security assessment identified SQL Injection vulnerabilities across several API endpoints. Below are some endpoints:

Endpoint	Method	Parameter
/admin/search/	GET	<injection>
/admin/appointments	GET	location
/user-admin/<id>	GET	<injection>
/appointments/unit/<id>	GET	<injection>

For example, inserting nefarious SQL text into forms such as ' OR 1=1 has resulted in unexpected data exposure or even errors in the SQL confirming the problematic vulnerability. Automated tools such as SQLmap further validate the impact potential by showing unauthorised retrieval of data.

Steps to Reproduce the Vulnerability

1. For each API endpoint, append a single quote (') or SQL payload (e.g., OR 1=1) to input parameters such as IDs or query strings.

2. Observe the application’s behavior. If SQL errors or unexpected data responses occur, the endpoint is vulnerable.

Recommendations for Mitigation

Addressing SQL Injection vulnerabilities requires a multi-faceted approach to ensure robust security:

1. Input Validation and Sanitization
   Validate all user inputs rigorously. Reject or escape special characters like quotes (', "), semicolons (;), and SQL keywords (SELECT, UNION, INSERT).

2. Use of Prepared Statements and Parameterized Queries
   Replace dynamic SQL queries with parameterized ones. This prevents user inputs from being executed as SQL code.

3. Limit Database Privileges
   Assign the minimum required privileges to database users. Avoid using administrative accounts for application-level queries.

4. Error Handling
   Implement generic error messages for users and ensure detailed SQL errors are logged securely.

5. Regular Security Audits
   Conduct routine security assessments and code reviews to identify and resolve SQL Injection vulnerabilities before they can be exploited.

Conclusion

SQL Injection remains a critical threat to API security, with the potential to compromise sensitive systems and data. Proactively identifying and addressing such vulnerabilities through best practices like input validation, prepared statements, and privilege management is crucial to maintaining a secure application environment.

At ESM Global Consulting, we specialize in securing applications against such threats. Contact us to learn how we can help protect your systems from SQL Injection and other vulnerabilities.