Understanding and Preventing Layer 7 Attacks
The open systems interconnection (OSI) is a reference model for layering interoperability and networking of communicating systems via standard protocols. Even though cybersecurity attacks can happen anywhere in the OSI model, Layer 7, or the application layer, is most vulnerable to threats. The application layer serves the end user and provides application-to-application communication services. Its accessibility provides a wide threat surface for attackers, and its complexity makes it the hardest to protect.
Let’s take a look at the most common application-layer attacks and how you can prevent them.
1. Cross-Site Request Forgery
A cross-site request forgery is when an attacker exploits the website’s trust in the user authentication session. The success of this attack relies on web applications failing to verify that incoming HTTP requests are from an authenticated user.
It makes an authenticated user perform unwanted actions, such as money transfers, password or email account changes, or sending HTTP requests to the web application.
2. Cross-Site Scripting
Cross-site scripting (XSS) is among the top security risks and is a concern for most businesses and organizations, as they tend to rely heavily on web applications.
An XSS attack is when someone exploits web application vulnerability to send malicious client-side JavaScript to compromise user interaction with the application. It’s a type of injection attack in which the attacker sends a malicious code not to the application, but to the end user.
XSS allows an attacker to execute malicious code in the browser of the authentic user to access data and display it as an immediate response. An XSS vulnerability also includes or stores data in the target server or database that reflects the malicious content or script every time a user visits the web page.
This allows an attacker to compromise the web application or take control of it if it’s an administrative or privileged user account.
3. SQL Injection (SQLi)
SQLi is another type of injection attack that performs backend database manipulation. It uses unvalidated user input or MySQL statement queries in the web application database. It allows attackers to bypass the application’s authentication and authorization measures to retrieve MySQL database content.
A successful attack can retrieve user lists and tables and perform database modification (alter/insert/delete), system-based command execution and administrative-level privileges.
SQLi is one of the biggest security risks to applications, and these injection attacks happen as a result of unsanitized or unfiltered data supply to the applications.
4. Application Layer DDoS
Application layer distributed denial-of-service (DDoS) attacks are low- to medium-volume attacks that target application vulnerabilities to make the service unavailable. Layer 7 DDoS attacks usually target specific web servers like Apache and BGP. This includes attacks like GET/POST flood attacks, Slowloris and large payload posts.
However, DDoS attacks are low-volume and complex to execute, as they require conformity with the application layer protocols.
5. Parameter Tampering
Parameter tampering refers to the manipulation of form fields or parameters inside the web page or URL.
The attacks can target parameters communicated between the client and server to modify credentials, product prices for application misuse or a third party via a man-in-the-middle attack.
The attack is made possible by taking advantage of the data inside HTTP headers, cookies, URL strings and hidden form fields. A successful tampering attack can lead to SQLi, XSS, path disclosure, or file inclusion attacks.
How to Prevent Layer 7 Attacks
Protecting the application layer from a growing list of attack vectors can be a daunting task, but here are some standard measures you can take:
1. Use a web application firewall (WAF) to stop data breaches
This protects web applications by monitoring, blocking and filtering incoming malicious HTTP requests and outgoing unauthorized data, acting as a reverse proxy.
2. Use input validation and sanitization
Input validation ensures front-end security by validating user-controlled input against predefined patterns. Similarly, sanitization applied before input validation cleans the incoming requests from unnecessary characters.
3. Output encoding and escaping
These techniques reduce the attack surface area over the application layer. They protect against injection attacks by responding to malicious requests without dangerous code execution and avoiding strings or special character misinterpretation.
4. Implement Content Security Policy (CSP)
This is a defensive standard to protect against XSS, clickjacking and other application-layer attacks that exploit trusted web contexts.
5. Determine what your “normal” is
This will help prevent DDoS attacks, as it will make abnormalities easier to identify. Use security-focused flow analysis with behavioral analysis or deep packet inspection to detect abnormal behavior.
Conclusion
After suffering many losses, many organizations and businesses have finally realized the importance of cybersecurity measures. Meanwhile, attackers continue to discover new vectors through which to access and compromise their data.
Application security can be difficult, but WAF implementation, continuous monitoring and scanning for new and old vulnerabilities can help you guard against these ever-evolving application-layer attacks.
