What Techniques Are Used in Web Application Firewalls (WAF) Bypass Attacks?

What Techniques Are Used in Web Application Firewalls (WAF) Bypass Attacks?

• As the number and intensity of malicious threat actors online have increased, we have come up with advanced cybersecurity measures as well. A Firewall is one such measure.
• Firewalls especially play an interesting role in ensuring a robust Web App Security Their job is to restrain external attackers from accessing the internal resources associated with the application.
• Businesses generally conduct web application pentesting to know how to deploy firewalls to optimize their security.
• However, firewalls are not 100% impenetrable. Advanced and evolved threat actors manage to somehow bypass them. Going further in the blog, we will discuss the techniques used by threat actors to bypass these firewalls…

Significance of Web Application Firewalls (WAF)

Web Application Firewalls (WAF) are vital for online security. They act as a shield, protecting websites and web applications from various cyber threats. WAFs monitor and filter HTTP traffic between a web application and the internet. This helps in identifying and blocking malicious activities like SQL injection, cross-site scripting, and other attacks. They analyze incoming requests and outgoing responses, applying predefined security rules to detect and block suspicious traffic. WAFs help prevent data breaches, unauthorized access, and the exploitation of vulnerabilities in web applications. By providing an additional layer of defense, WAFs enhance the overall security posture of websites. Plus, they ensure safer online experiences for users and businesses alike.

What Techniques Do Hackers Use to Bypass Web Application Firewalls (WAF)?

Hackers use the following techniques to bypass WAF and breach your Web App Security:

1. Protocol Manipulation:

Hackers may manipulate the communication protocol to disguise malicious payloads. For example, they can split an attack payload across multiple requests or obfuscate it within legitimate traffic.

2. IP Address Spoofing:

By spoofing their IP addresses, attackers can bypass IP-based blocking rules enforced by the WAF. Eventually making it difficult to filter out malicious requests.

3. HTTP Parameter Pollution (HPP):

In HPP attacks, hackers manipulate parameters in HTTP requests to confuse the WAF and bypass security controls. They inject additional parameters or modify existing ones to evade detection.

4. Session Riding (Session Fixation):

Attackers exploit session management vulnerabilities to hijack user sessions or gain unauthorized access to accounts. By bypassing session management controls, they can evade detection by the WAF.

5. Slow HTTP DoS (Denial of Service):

This technique involves sending HTTP requests slowly to consume server resources and exhaust connection limits. By launching slow HTTP DoS attacks, hackers can overwhelm the WAF and bypass security measures.

6. Encoding and Obfuscation:

Hackers may encode or obfuscate malicious payloads using techniques like base64 encoding, character encoding, or encryption. It helps them evade signature-based detection by the WAF.

7. File Upload Exploits:

Attackers exploit vulnerabilities in file upload functionalities to upload malicious files to the server. By bypassing the content inspection mechanisms of the WAF, they can execute arbitrary code and conduct further attacks.

8. Evasion through Encapsulation:

Hackers encapsulate malicious payloads within legitimate data formats or protocols to bypass content inspection by the WAF. For example, they may hide malicious code within image files or use covert channels to transmit data.

9. Bypassing Whitelisting/Blacklisting:

Attackers may attempt to evade detection by exploiting weaknesses in the WAF’s whitelisting or blacklisting rules. They may use alternative attack vectors or manipulate input parameters to bypass security controls.

10. Zero-Day Exploits:

Hackers leverage previously unknown vulnerabilities (zero-day exploits) to bypass WAF protections. By exploiting newly discovered vulnerabilities, attackers can evade signature-based detection and launch successful attacks.

Overall, hackers continuously adapt their tactics to evade detection by Web Application Firewalls. This highlights the importance of implementing comprehensive security measures and regularly updating WAF configurations to mitigate emerging threats.

Optimize the Use of Firewalls to Boost Your Web App Security

The following are some of the best practices regarding the use of web application firewalls:

1. Implement Layered Protection:

Deploy multiple layers of firewalls, including network, host-based, and web application firewalls (WAFs), to defend against different types of attacks.

2. Keep Firewalls Updated:

Regularly update firewall software and firmware to patch known vulnerabilities and ensure optimal protection against evolving threats.

3. Follow Least Privilege Principle:

Configure firewall rules to enforce the principle of least privilege, granting only necessary network access rights to users and applications.

4. Enable Intrusion Prevention Systems (IPS):

Combine firewalls with IPS to detect and block suspicious network traffic and prevent intrusion attempts in real time.

5. Segment Network Traffic:

Segment your network into zones and apply firewall rules to control traffic flow between zones. This helps in limiting the impact of potential breaches and reducing the attack surface.

Before You Go!

• Even though hackers have found multiple ways to bypass Web Application Firewalls. But they are still your best hope to fortify your Web Application Security.
• All you need to do is to keep updated with the latest techniques and ideas regarding the use of firewalls.
• You can also get help from the experts out there.