CVE-2006-6965 in DokuWiki
Summary
by MITRE
CRLF injection vulnerability in lib/exe/fetch.php in DokuWiki 2006-03-09e, and possibly earlier, allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via CRLF sequences in the media parameter. NOTE: this issue can be leveraged for XSS attacks.
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Analysis
by VulDB Data Team • 07/13/2021
The CVE-2006-6965 vulnerability represents a critical CRLF injection flaw in DokuWiki's fetch.php script that enables remote attackers to manipulate HTTP headers and execute HTTP response splitting attacks. This vulnerability specifically affects DokuWiki versions up to and including the 2006-03-09e release, with potential impacts extending to earlier versions. The flaw occurs within the media parameter handling mechanism where CRLF sequences can be injected, allowing attackers to inject malicious HTTP headers into the response stream. This injection capability fundamentally compromises the integrity of HTTP communications by enabling attackers to inject arbitrary headers that can alter how web browsers process subsequent responses.
The technical exploitation of this vulnerability stems from insufficient input validation and sanitization within the fetch.php script's parameter processing. When the media parameter contains CRLF characters, these sequences are not properly escaped or filtered before being incorporated into HTTP headers. This creates an avenue for attackers to inject malicious headers such as Set-Cookie, Location, or Content-Type directives, which can redirect users to malicious sites or inject malicious content into web responses. The vulnerability operates at the HTTP protocol level where the application fails to properly validate and sanitize user-supplied input before incorporating it into HTTP response headers, directly violating secure coding principles for input validation.
The operational impact of this vulnerability extends beyond simple HTTP response splitting to include significant cross-site scripting capabilities. Attackers can leverage the header injection to craft malicious responses that include JavaScript payloads, enabling XSS attacks against unsuspecting users. This dual nature makes the vulnerability particularly dangerous as it can be used to establish persistent attack vectors through cookie manipulation, redirect users to phishing sites, or inject malicious scripts that can harvest user credentials or session information. The vulnerability essentially allows attackers to manipulate the entire HTTP response flow, creating opportunities for various attack vectors including session hijacking, data exfiltration, and user impersonation.
Mitigation strategies for this vulnerability require immediate implementation of proper input sanitization and validation mechanisms. Organizations should ensure that all user-supplied input, particularly parameters used in HTTP header construction, undergo thorough validation to remove or encode CRLF sequences. The fix involves implementing strict input filtering that strips or encodes characters such as carriage return and line feed sequences before they can be processed in HTTP header contexts. Additionally, implementing proper HTTP header generation practices that separate user input from header construction using proper encoding mechanisms prevents injection attacks. Organizations should also consider implementing Content Security Policy headers and other security measures to reduce the impact of potential XSS exploitation. This vulnerability aligns with CWE-113, which addresses improper neutralization of CRLF sequences in HTTP headers, and maps to ATT&CK technique T1189, which covers HTTP response splitting attacks, emphasizing the need for comprehensive input validation across all HTTP response generation components.
The broader implications of this vulnerability highlight the critical importance of secure coding practices in web applications, particularly in the handling of user input within HTTP contexts. This flaw demonstrates how seemingly simple input validation issues can create cascading security problems that enable multiple attack vectors. Organizations must implement robust security testing procedures that include input validation testing, HTTP header injection testing, and comprehensive security reviews of all application components that interact with user-supplied data. The vulnerability also underscores the need for regular security updates and patch management processes, as the affected DokuWiki versions are from 2006, indicating that proper maintenance and update practices are essential for maintaining application security.