CVE-2002-1845 in YaBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in Yet Another Bulletin Board (YaBB) 1.40 and 1.41 allows remote attackers to inject arbitrary web script or HTML via the password (passwrd) parameter.
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Analysis
by VulDB Data Team • 09/01/2025
The vulnerability identified as CVE-2002-1845 represents a classic cross-site scripting flaw within the Yet Another Bulletin Board version 1.40 and 1.41 web applications. This security weakness resides in the index.php file where user input is not properly sanitized before being rendered back to web browsers. The specific attack vector targets the password parameter named passwrd which is processed without adequate validation or encoding mechanisms. This allows malicious actors to inject arbitrary web scripts or HTML content that executes in the context of other users' browsers when they access the affected application.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding practices within the YaBB bulletin board software. When users submit data through the password field, the application fails to properly escape or filter special characters that could be interpreted as HTML or JavaScript code. This lack of proper sanitization creates an environment where attackers can craft malicious payloads that bypass the application's security controls. The vulnerability is classified as a reflected XSS attack since the malicious script is reflected back to users through the application's response to their input. According to CWE-79, this represents a weakness where applications fail to properly encode or escape user-controllable data before incorporating it into dynamically generated content, making it executable in the victim's browser context.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it enables attackers to execute arbitrary code within users' browsers. An attacker could potentially steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The vulnerability affects all users of the affected YaBB versions, making it particularly dangerous for bulletin board systems where multiple users interact with shared content. The attack requires minimal sophistication since it leverages the existing authentication mechanism to deliver malicious payloads, making it an attractive target for automated exploitation campaigns. This vulnerability directly aligns with ATT&CK technique T1566.001 which describes the use of credential harvesting through phishing and social engineering techniques, where the XSS vulnerability provides the initial exploitation vector for more sophisticated attacks.
Mitigation strategies for CVE-2002-1845 require immediate implementation of proper input validation and output encoding mechanisms. The most effective approach involves implementing strict sanitization of all user inputs, particularly those that are reflected back to users in web responses. This includes applying HTML entity encoding to all dynamic content before rendering, implementing proper content security policies, and ensuring that the application does not trust any user-supplied data without thorough validation. Organizations should also consider implementing web application firewalls to detect and block malicious payloads, while upgrading to patched versions of YaBB or migrating to more secure bulletin board solutions. The vulnerability demonstrates the critical importance of input validation as outlined in OWASP Top 10 A03:2021, where insufficient logging and monitoring of security events can compound the impact of such XSS vulnerabilities. Regular security assessments and code reviews should be implemented to identify similar weaknesses in other application components, as this vulnerability represents a common pattern that has plagued web applications for decades.