Application layer attacks

Attacks targeting the application layer (Layer 7) are increasingly on the rise, with the application layer now being among one of the top three attack vectors. For cyber defenders, especially those working within the security operations center (SOC), it’s critical to understand how these attacks work and how to effectively defend against them.

This guide explains how application layer attacks work and highlights how Contrast Application Detection and Response (ADR) empowers SOC analysts and managers to stop them. Learn more about how ADR cuts through the noisy false positives and false negatives of Web Application Firewall (WAF) alerts, providing the SOC with only verified, actionable attack data, enabling faster and more focused response.

What is an application layer attack?

An application layer attack exploits vulnerabilities in Layer 7 of the OSI model, attacking the application’s code, logic, or functionality—unlike network or endpoint layer attacks, which target infrastructure. Application attacks are harder to detect because they blend in with legitimate traffic and require deep knowledge of the application to execute. 

Attackers use these exploits for various purposes, such as:

• Stealing sensitive data
• Disrupting availability (Denial of Service)
• Gaining unauthorized access
• Manipulating application functionality

Application layer attacks are frequently a component of a multi-stage attack campaign. A successful application layer exploit can serve as the initial access point, enabling attackers to pivot laterally to achieve broader objectives. In essence, application layer attacks go beyond simply flooding a network with traffic; they aim to exploit the inner workings of the applications people use.

How do application layer attacks work?

Application layer attacks leverage various techniques to manipulate or compromise application functionality. Attackers exploit vulnerabilities such as:

• Input validation flaws: Failing to properly sanitize user inputs.
• Authentication and authorization weaknesses: Bypassing security controls.
• Session management issues: Hijacking user sessions.

These attacks often involve sending malicious requests designed  to extract sensitive data, modify application behavior or disrupt services.

Examples and types of application layer attacks

Common types of application layer attacks include:

• SQL Injection (SQLi): Injecting malicious SQL code into application inputs to manipulate database queries.
• Cross-Site Scripting (XSS): Injecting malicious scripts into websites viewed by other users.
• Cross-Site Request Forgery (CSRF): Forcing authenticated users to execute unwanted actions.
• Remote Code Execution (RCE): Exploiting vulnerabilities to execute arbitrary code on the server.
• Untrusted Deserialization: A security vulnerability that arises when an application deserializes (converts serialized data back into an object) data from an untrusted source without proper validation.
• Method Tampering (aka HTTP verb tampering): An attack against authentication or authorization systems that have implicit "allow all" settings in their security configuration. This type of attack takes advantage of vulnerabilities in HTTP verb authentication (also known as HTTP method authentication) and access control mechanisms.
• Object-Graph Navigation Language (OGNL) EL injection: Object-Graph Navigation Language is an open-source Expression Language (EL) for Java objects. OGNL expression injection attacks enable evaluation of invalidated expressions against the value stack, allowing an attacker to modify system variables or execute arbitrary code.
• Path Traversal: Also known as directory traversal, it’s a web security vulnerability that allows an attacker to access files and directories that are located outside the web root folder.
• Command Injection: With a command injection attack, an attacker can hijack a vulnerable application in order to execute arbitrary commands on the host operating system.
• JNDI Injection: Verifies that no untrusted data is used in a Java Naming and Directory Interface (JNDI) lookup.
• Denial of Service (DoS/DDoS): Overwhelming the application with traffic to disrupt service availability. DDoS attacks are difficult to stop because the server can’t distinguish between the DDoS attack and normal traffic.

These attacks are often listed in the OWASP Top 10, highlighting their prevalence and severity.

How to detect an application layer attack

Traditional security tools like firewalls and intrusion detection systems (IDS) often struggle to detect application layer attacks due to their focus on network traffic. To protect web applications in production, many teams today use Web Application Firewalls (WAFs). A WAFfilters and monitors HTTP traffic to protect web applications, along with log analysis. SOC analysts can then manually examine application logs for suspicious patterns and anomalies.

WAFs, while helpful, are susceptible to relatively simple spoofing techniques, allowing attackers to bypass them. Furthermore, manual log analysis is prone to errors due to the sheer volume of data and the potential for human oversight, leading to missed threats and faulty tuning.

Contrast ADR: Enhanced visibility and rapid response

Contrast ADR provides SOC analysts with unparalleled visibility into application layer attacks. By leveraging instrumentation within the application itself, Contrast ADR detects attacks in real time, providing detailed context and actionable insights. This enables SOC teams to do the following:

• Identify and prioritize critical vulnerabilities.
• Rapidly respond to active attacks.
• Reduce false positives and improve incident response efficiency.
• Gain comprehensive attack telemetry for forensic analysis.

For SOC managers, Contrast ADR offers a proactive approach to application security, reducing risk and improving overall security posture.

How Contrast ADR empowers SOC teams to take control of application security

Traditionally, SOC teams have limited visibility and control over the application layer. They often rely on Application Security teams and developers to address application vulnerabilities and have limited visibility and response capabilities to application and API attacks.

Faced with an application attack, the SOC's response options are often limited and inadequate. Blocking IP addresses is easily circumvented, and taking an application offline is highly disruptive to the business. The SOC needs direct control to take more precise and effective action.

When the SOC does identify a potential application attack, analysts must communicate the issue to the AppSec and/or development teams. This often involves providing incomplete or imprecise data (e.g., IP addresses, timestamps, general alert descriptions) because the SOC lacks application-layer context. Developers then need to spend valuable time investigating the reported issue, trying to reproduce the attack, and pinpoint the vulnerable code. While this happens the organization remains vulnerable to the attack.

This dependency on other teams, lack of control and visibility leaves the SOC powerless against application-layer threats, increasing risk and hindering efficiency. Contrast ADR directly addresses this, empowering the SOC with the tools and insights to take control.

How to mitigate an application layer attack

Effective mitigation involves both preventing attacks and responding quickly when they occur:

• Secure coding practices: Minimize vulnerabilities from the start.
• Input validation and sanitization: Prevent injection attacks.
• Access control: Strengthen authentication and authorization.
• Regular security testing: Identify and remediate vulnerabilities.  
• Patch management: Keeping applications and libraries up-to-date.
• Incident response plan: Ensure quick and effective response to threats.

Contrast ADR complements these strategies by providing real-time protection and detailed attack information, enabling rapid and effective mitigation.

Key benefits of Contrast ADR for mitigating application layer attacks

• Enabling actionable responses: Stop application and API attacks in real-time without the need to involve development teams in-the-moment. ADR empowers the SOC to independently intervene at the first signs of an application attack, preventing escalation and protecting critical assets.
• Providing precise remediation guidance: ADR equips the SOC with pre-built runbooks, translating complex application triage into clear, actionable steps. Follow straightforward instructions to neutralize threats and protect applications and APIs. Contrast ADR gives the SOC the crucial code-level context needed to quickly and accurately inform developers of vulnerabilities, ensuring rapid and effective fixes.
• Ensuring enhanced SOC efficiency: Contrast ADR integrates application security into the existing SOC workflow. Shared attack insights between the SOC and development foster a common understanding and streamline remediation workflows. Contrast ADR enables the SOC to proactively identify, assess and manage application security risks.

By understanding application layer attacks and leveraging advanced solutions like Contrast ADR, organizations can strengthen their security posture and protect their critical applications.