CVE-2006-0639 in MyBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in search.php in MyBB (aka MyBulletinBoard) 1.0.2 allows remote attackers with knowledge of the table prefix to inject arbitrary web script or HTML via a URL encoded value of the keywords parameter, as demonstrated by %3Cscript%3E.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/30/2019
The vulnerability identified as CVE-2006-0639 represents a critical cross-site scripting flaw discovered in MyBB version 1.0.2's search.php script. This weakness enables remote attackers to execute malicious code within the context of other users' browsers through carefully crafted input parameters. The vulnerability specifically targets the keywords parameter which processes user search queries without adequate input sanitization or output encoding mechanisms. Attackers can exploit this by submitting URL-encoded script tags through the search functionality, allowing them to inject arbitrary web scripts or HTML content into the application's response. The attack requires knowledge of the database table prefix, which suggests that the vulnerability may be more difficult to exploit in environments where this information is properly obscured or protected.
The technical nature of this flaw aligns with CWE-79, which defines the classic cross-site scripting vulnerability where untrusted data is improperly incorporated into web page content without appropriate validation or encoding. This weakness allows attackers to manipulate the application's behavior and potentially gain unauthorized access to user sessions, steal sensitive information, or perform actions on behalf of authenticated users. The vulnerability's exploitation demonstrates how insufficient input validation can create persistent security risks within web applications, particularly in forum platforms where user-generated content is common and trusted. The specific URL encoding technique used in the demonstration (%3Cscript%3E) represents a standard method for bypassing basic input filtering mechanisms and injecting malicious code into web applications.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform session hijacking, steal cookies, redirect users to malicious websites, or even execute more sophisticated attacks through the compromised user sessions. In the context of a bulletin board system like MyBB, where users may have varying levels of permissions and access rights, this vulnerability could allow attackers to escalate privileges or gain unauthorized access to administrative functions. The requirement for knowledge of the table prefix suggests that the vulnerability may be mitigated through proper database configuration and access controls, but this also indicates that attackers with sufficient reconnaissance capabilities could still exploit the flaw effectively. This type of vulnerability is particularly dangerous in multi-user environments where users may be unaware of the malicious code execution occurring within their browser context.
Mitigation strategies for CVE-2006-0639 should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application. The most effective immediate solution involves sanitizing all user input parameters, particularly those used in search functions, by removing or encoding potentially dangerous characters and script tags. Application developers should implement proper HTML escaping routines before rendering any user-supplied content in web responses, ensuring that special characters are properly encoded to prevent interpretation as executable code. Additionally, organizations should consider implementing Content Security Policy headers to add an additional layer of protection against script injection attacks. The vulnerability also highlights the importance of keeping software updated, as this specific version of MyBB was vulnerable to such attacks, and newer releases would have addressed these security concerns through proper input validation and sanitization mechanisms. This case demonstrates the critical importance of following secure coding practices and implementing defense-in-depth strategies to protect against common web application vulnerabilities as outlined in the ATT&CK framework's web application attacks category.