CVE-2007-1262 in SquirrelMail
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the HTML filter in SquirrelMail 1.4.0 through 1.4.9a allow remote attackers to inject arbitrary web script or HTML via the (1) data: URI in an HTML e-mail attachment or (2) various non-ASCII character sets that are not properly filtered when viewed with Microsoft Internet Explorer.
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Analysis
by VulDB Data Team • 08/10/2022
The vulnerability identified as CVE-2007-1262 represents a significant cross-site scripting weakness affecting SquirrelMail versions 1.4.0 through 1.4.9a, specifically within the HTML filter component that processes email attachments. This flaw exploits the inadequate sanitization of data streams when rendering HTML content, creating opportunities for malicious actors to execute arbitrary scripts in the context of a user's browser session. The vulnerability manifests through two distinct attack vectors that leverage different aspects of HTML processing and character encoding.
The first exploitation vector involves the manipulation of data: URIs within HTML email attachments, while the second targets non-ASCII character sets that fail to be properly filtered when rendered through Microsoft Internet Explorer. These attack surfaces demonstrate a fundamental weakness in the HTML sanitization process where the application does not adequately validate or escape potentially dangerous content before displaying it to users. The vulnerability is particularly concerning because it affects the core email rendering functionality of the webmail client, making it a prime target for attackers seeking to compromise user sessions.
From an operational perspective, this vulnerability enables remote attackers to execute malicious scripts in the context of a victim's browser, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the user. The attack requires minimal privileges and can be executed through standard email delivery mechanisms, making it particularly dangerous in environments where users regularly access email through web interfaces. The exploitation is further amplified by the widespread use of Microsoft Internet Explorer, which was the dominant browser at the time of this vulnerability's discovery.
The technical implementation of this vulnerability aligns with CWE-79, Cross-site Scripting, and demonstrates characteristics consistent with ATT&CK technique T1566.001, Phishing via Social Engineering, as attackers can craft malicious emails that exploit these vulnerabilities to compromise user systems. The HTML filter's failure to properly sanitize data: URIs and non-ASCII character sets creates persistent security gaps that allow attackers to inject malicious JavaScript code or HTML content. This weakness stems from inadequate input validation and output encoding practices, where the application assumes that certain character encodings or URI schemes are safe without proper sanitization.
Mitigation strategies should focus on implementing comprehensive input validation and output encoding mechanisms throughout the email processing pipeline. The most effective approach involves upgrading to a patched version of SquirrelMail that properly sanitizes all HTML content and implements robust character encoding handling. Organizations should also consider implementing additional security measures such as content security policies, email filtering solutions, and user education regarding suspicious email attachments. The vulnerability highlights the critical importance of proper HTML sanitization in web applications and demonstrates how seemingly benign features like email attachment handling can become attack vectors when proper security controls are not implemented.