CVE-2006-1282 in MyBB
Summary
by MITRE
CRLF injection vulnerability in inc/function.php in MyBulletinBoard (MyBB) 1.04 allows remote attackers to conduct cross-site scripting (XSS), poison caches, or hijack pages via CRLF (%0A%0D) sequences in the Referrer HTTP header field, possibly when redirecting to other web pages.
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Analysis
by VulDB Data Team • 04/30/2019
The vulnerability identified as CVE-2006-1282 represents a critical cross-site scripting weakness in MyBulletinBoard version 1.04, specifically within the inc/function.php file. This flaw stems from inadequate input validation of the HTTP Referrer header field, which allows malicious actors to inject carriage return line feed sequences directly into the application's processing pipeline. The vulnerability operates by exploiting the lack of proper sanitization when handling user-supplied data in the Referrer header, enabling attackers to manipulate HTTP response headers through crafted CRLF sequences encoded as %0A%0D. The security implications extend beyond simple XSS attacks, as this injection vector can be leveraged to poison web caches, hijack web pages, and potentially redirect users to malicious destinations through header manipulation techniques that are commonly used in web application attacks.
The technical exploitation of this vulnerability relies on the application's failure to properly validate and sanitize HTTP header inputs before processing them in redirect operations. When MyBB processes a request containing a malicious Referrer header with injected CRLF sequences, the application's header handling mechanism fails to strip or encode these dangerous characters, allowing them to be interpreted as actual HTTP header terminators. This creates a condition where an attacker can inject additional headers into the HTTP response, potentially modifying the response behavior in ways that facilitate further attacks. The vulnerability specifically affects the redirect functionality of the bulletin board software, making it particularly dangerous for a platform that frequently performs URL redirection operations. This weakness aligns with CWE-113, which describes improper neutralization of CRLF characters in HTTP headers, and represents a classic example of how header injection vulnerabilities can be exploited in web applications.
The operational impact of CVE-2006-1282 is significant for any organization running MyBulletinBoard 1.04, as it provides attackers with multiple attack vectors beyond simple XSS. The ability to poison caches means that legitimate users may be served malicious content from cached responses, while page hijacking capabilities allow attackers to redirect users to phishing sites or malicious domains. The vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous for publicly accessible bulletin board systems. Attackers can leverage this weakness to perform session hijacking, inject malicious JavaScript code into pages, or manipulate the application's redirect behavior to direct users to compromised websites. The attack surface is further expanded because many bulletin board systems use the Referrer header for various operational purposes, including logging, analytics, and user tracking, making this vulnerability particularly insidious.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and sanitization measures for all HTTP headers, particularly the Referrer field. Organizations should immediately upgrade to a patched version of MyBulletinBoard, as the vulnerability was addressed in subsequent releases through proper header sanitization. The recommended approach involves implementing strict validation that removes or encodes CRLF characters from all HTTP header inputs before processing, following the principle of least privilege in header handling. Security measures should include configuring web application firewalls to detect and block suspicious header patterns, implementing proper output encoding for all dynamic content, and establishing regular security audits of header processing functions. Additionally, administrators should consider implementing Content Security Policy headers to provide additional protection against XSS attacks, while following ATT&CK framework techniques for detecting and preventing header injection attacks. The vulnerability serves as a reminder of the critical importance of proper input validation in web applications and the potential for seemingly benign header fields to become attack vectors when not properly secured.