CVE-2004-0310 in LiveJournal
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in LiveJournal 1.0 and 1.1 allows remote attackers to execute Javascript as other users via the stylesheet, which does not strip the semicolon or parentheses, as demonstrated using a background:url.
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Analysis
by VulDB Data Team • 07/08/2017
The vulnerability identified as CVE-2004-0310 represents a critical cross-site scripting flaw within LiveJournal versions 1.0 and 1.1 that enables remote attackers to inject malicious javascript code into user sessions. This vulnerability specifically targets the stylesheet handling mechanism within the blogging platform, where input validation fails to properly sanitize user-supplied content. The flaw occurs when the system processes stylesheet parameters without adequately filtering dangerous characters including semicolons and parentheses that are essential components for executing javascript code within css url functions. Attackers can exploit this weakness by crafting malicious stylesheet entries that leverage the background:url css property to embed javascript payloads, effectively bypassing standard security measures that might otherwise prevent direct script injection. The vulnerability operates under CWE-79 which classifies it as a cross-site scripting weakness, specifically demonstrating how insufficient input sanitization can lead to unauthorized code execution in web applications.
The technical exploitation of this vulnerability relies on the ability to inject malicious content through the stylesheet parameter handling system where the application fails to properly validate or sanitize user inputs. When a user views a page containing a maliciously crafted stylesheet, the browser executes the embedded javascript code with the privileges of the victim user, potentially leading to session hijacking, data theft, or further malicious activities. The specific use of background:url demonstrates how css-based attack vectors can be leveraged to execute javascript code, representing an advanced exploitation technique that bypasses traditional input validation approaches. This vulnerability aligns with ATT&CK technique T1059.007 which covers script-based execution through CSS properties, showing how attackers can utilize less obvious attack vectors to achieve code execution. The failure to strip semicolons and parentheses from stylesheet inputs creates a pathway for attackers to construct functional javascript payloads that can be executed within the context of legitimate user sessions.
The operational impact of this vulnerability extends beyond simple data theft or session manipulation, as it represents a fundamental flaw in the web application's security architecture that could enable attackers to compromise entire user bases. When exploited, this vulnerability allows attackers to execute javascript code as if they were the legitimate user, potentially leading to unauthorized access to personal information, message manipulation, or even account takeovers. The vulnerability affects all users of LiveJournal 1.0 and 1.1 versions, creating a widespread security risk across the platform's user community. The impact is particularly severe because it operates at the presentation layer where users expect to see only legitimate content, making the malicious code execution more likely to go unnoticed. This type of vulnerability represents a critical failure in the principle of least privilege and demonstrates how improper input validation can create persistent security risks that affect multiple users simultaneously.
Mitigation strategies for this vulnerability require immediate implementation of proper input sanitization and output encoding mechanisms within the stylesheet handling components of LiveJournal. Organizations should implement comprehensive filtering of all user-supplied content, particularly focusing on css properties and their associated parameters to prevent dangerous characters from being processed. The solution must include robust validation that removes or encodes semicolons, parentheses, and other potentially dangerous elements from stylesheet inputs. Additionally, implementing a content security policy that restricts the execution of inline javascript and limits the use of css url functions can provide additional protection layers. Regular security audits and input validation testing should be conducted to prevent similar vulnerabilities from emerging in future releases. The fix should align with industry best practices for XSS prevention as outlined in OWASP Top 10 and should include proper encoding of all dynamic content before rendering to prevent malicious code execution. Organizations should also consider implementing web application firewalls and monitoring systems to detect and prevent exploitation attempts against known vulnerable patterns.