CVE-2011-4139 in Django
Summary
by MITRE
Django before 1.2.7 and 1.3.x before 1.3.1 uses a request s HTTP Host header to construct a full URL in certain circumstances, which allows remote attackers to conduct cache poisoning attacks via a crafted request.
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Analysis
by VulDB Data Team • 11/24/2021
The vulnerability described in CVE-2011-4139 represents a significant security flaw in the Django web framework that existed prior to specific version releases. This issue stems from Django's handling of HTTP Host headers during URL construction processes, creating an avenue for malicious actors to manipulate application behavior through carefully crafted requests. The vulnerability specifically affects Django versions before 1.2.7 and 1.3.x versions before 1.3.1, indicating a widespread impact across multiple release lines that were commonly used in production environments during that time period.
The technical flaw manifests when Django processes HTTP Host headers to generate full URLs for various application functions including redirects, cache keys, and internal URL resolution. When the framework relies on the Host header without proper validation or sanitization, attackers can inject malicious host values that alter how URLs are constructed and processed. This particular implementation flaw allows for cache poisoning attacks because the vulnerable code path uses the untrusted Host header value directly in URL generation, bypassing normal security checks that would typically validate or sanitize such input. The vulnerability operates at the application layer and specifically targets the framework's URL resolution mechanisms.
The operational impact of this vulnerability extends beyond simple cache manipulation to potentially enable more serious attacks including open redirectors, session hijacking, and cross-site scripting scenarios. When attackers successfully poison caches with malicious URLs, they can influence how subsequent requests are handled, potentially redirecting users to malicious sites or injecting harmful content into the application's response handling. This vulnerability particularly affects web applications that rely on Django's built-in URL handling and caching mechanisms, making it a critical concern for organizations maintaining legacy Django installations. The attack vector requires only a single malicious request to establish the cache poisoning state, making it particularly dangerous in production environments where caching is extensively used.
Mitigation strategies for CVE-2011-4139 focus primarily on upgrading to patched versions of Django where the Host header validation has been properly implemented. Organizations should immediately update their Django installations to versions 1.2.7 or 1.3.1 and later, as these releases contain the necessary security patches. Additionally, administrators should implement proper input validation at the application level and consider deploying web application firewalls to monitor and filter malicious Host header values. The vulnerability aligns with CWE-1107 which specifically addresses improper validation of HTTP Host headers, and it maps to ATT&CK technique T1071.004 for application layer protocol manipulation. Security teams should also conduct thorough code reviews to ensure no custom implementations are vulnerable to similar Host header manipulation attacks, particularly in legacy code that may not have been updated to follow modern security practices.