HTTP Response Splitting Template

Executive Summary:

This report addresses a critical security vulnerability known as HTTP Response Splitting within our application. HTTP Response Splitting occurs when untrusted input is included in HTTP response headers without proper sanitization, allowing attackers to inject additional headers and potentially manipulate client-side behavior. This report aims to detail the vulnerability, its potential impact on our systems and users, and actionable recommendations for mitigation.

Description of the Vulnerability:

HTTP Response Splitting vulnerabilities arise when user-controlled input is included in HTTP response headers without proper validation or encoding. Attackers can exploit these vulnerabilities to insert additional headers into HTTP responses, leading to various security risks such as cache poisoning, session fixation, or cross-site scripting (XSS) attacks. Common examples include injecting malicious headers to manipulate cookie values, redirect users to malicious sites, or inject arbitrary content into response headers.

Impact:

The impact of HTTP Response Splitting vulnerabilities can be severe, leading to various security risks including data leakage, session hijacking, or client-side code execution. Attackers can exploit these vulnerabilities to inject malicious headers, manipulate client-side behavior, or bypass security controls, potentially leading to unauthorized access, data breaches, or compromise of user sessions.

Likelihood:

The likelihood of exploitation depends on various factors including the visibility of user-controlled input in HTTP response headers, the effectiveness of input validation and encoding mechanisms, and the attacker's knowledge and motivation. However, given the prevalence of HTTP Response Splitting vulnerabilities in web applications and the potential impact on system security and user privacy, the risk associated with this vulnerability is significant if not properly mitigated.

Steps to Reproduce:

  1. Identify functionalities within the application that include user-controlled input in HTTP response headers, such as HTTP redirections, cookies, or custom headers.
  2. Inject malicious input containing newline characters or special characters into the user-controlled input fields.
  3. Observe the application's response and analyze if the injected input is reflected in the HTTP response headers without proper sanitization.
  4. Determine the impact of successful exploitation, including potential data leakage, session manipulation, or client-side code execution, on user security and system integrity.

Recommendations for Developers:

  1. Validate and Encode User Input: Validate and encode user-controlled input before including it in HTTP response headers to prevent injection of malicious characters or sequences.
  2. Use Security Libraries: Utilize security libraries or frameworks that provide built-in protection against HTTP Response Splitting vulnerabilities, such as encoding functions for header values.

Conclusion:

Addressing the HTTP Response Splitting vulnerability is critical to protecting the integrity and confidentiality of HTTP responses, preventing injection attacks, and maintaining trust within our application. By implementing proper input validation and encoding mechanisms, we can mitigate the risks associated with HTTP Response Splitting vulnerabilities and enhance the overall security posture of our systems.