CVE-2006-4761 in SharpReader
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Luke Hutteman SharpReader allow remote attackers to inject arbitrary web script or HTML via a web feed, as demonstrated by certain test cases of the Robert Auger and Caleb Sima RSS and Atom feed reader test suite.
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Analysis
by VulDB Data Team • 09/22/2017
The vulnerability identified as CVE-2006-4761 represents a critical cross-site scripting flaw in SharpReader, a popular RSS feed reader application developed by Luke Hutteman. This vulnerability specifically affects the application's handling of web feed data, creating a pathway for remote attackers to execute malicious scripts within the context of users' browsers. The flaw resides in the application's insufficient input validation and output sanitization mechanisms when processing RSS and Atom feed content, making it susceptible to injection attacks that can compromise user security and privacy.
The technical implementation of this vulnerability stems from SharpReader's failure to properly sanitize user-supplied feed data before rendering it in the application's user interface. When the application processes feeds from external sources, it does not adequately filter or escape special characters that could be interpreted as HTML or JavaScript code. This allows attackers to craft malicious feed entries containing embedded scripts that execute when users view the compromised feeds. The vulnerability is particularly concerning because RSS feeds are often consumed automatically by applications, meaning users may inadvertently execute malicious code without realizing they have been compromised. The attack vector specifically leverages the test cases from the Robert Auger and Caleb Sima RSS and Atom feed reader test suite, which demonstrates how various feed formats can be manipulated to exploit the application's weak input validation.
The operational impact of this vulnerability extends beyond simple script execution, creating significant risks for users who rely on SharpReader for consuming news and information feeds. Attackers can exploit this flaw to steal session cookies, redirect users to malicious websites, inject phishing content, or perform other malicious activities that compromise user accounts and data. The vulnerability affects all users who consume feeds from potentially compromised sources, making it particularly dangerous in environments where users may not be aware of the source authenticity. Given that RSS feeds are commonly used for news aggregation, blog subscriptions, and other information consumption activities, the potential attack surface is extensive. The vulnerability also represents a significant concern for organizations that may have deployed SharpReader in corporate environments, as it could serve as a vector for broader security breaches.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and output sanitization measures within the application. The most effective approach involves sanitizing all feed data before rendering it in the user interface, ensuring that potentially dangerous characters and script tags are properly escaped or removed. Security patches should include comprehensive filtering of user-supplied content, with particular attention to common XSS attack patterns such as script tag injection, event handler injection, and other malicious payload formats. Organizations should also implement feed source validation mechanisms to identify and block suspicious content, while maintaining regular updates to ensure protection against evolving attack techniques. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities, and represents a classic example of how insecure data handling can create persistent security risks in web applications. The flaw also demonstrates the importance of following secure coding practices and adhering to ATT&CK framework principles for preventing injection attacks, particularly those targeting web applications through content consumption mechanisms.