CVE-2005-2820 in SqWebMail
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in SqWebMail 5.0.4 allows remote attackers to inject arbitrary web script or HTML via an e-mail message containing Internet Explorer "Conditional Comments" such as "[if]" and "[endif]".
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Analysis
by VulDB Data Team • 07/05/2021
The vulnerability identified as CVE-2005-2820 represents a critical cross-site scripting flaw in SqWebMail version 5.0.4 that enables remote attackers to execute malicious scripts within victim browsers. This vulnerability specifically exploits the email client's insufficient input validation mechanisms when processing incoming email messages containing Internet Explorer conditional comments. The flaw resides in how the application handles email content without proper sanitization, creating an avenue for attackers to embed malicious code that executes when users view infected messages. The vulnerability is categorized under CWE-79 - Improper Neutralization of Input During Web Page Generation, which directly relates to the failure to properly sanitize user-supplied data before incorporating it into web page output.
The technical implementation of this vulnerability leverages Internet Explorer's conditional comment syntax as a delivery mechanism for malicious payloads. Attackers can craft email messages containing strings such as "[if]" and "[endif]" that, when processed by SqWebMail, get rendered directly into the web interface without proper HTML escaping or filtering. These conditional comments, while legitimate IE syntax for browser-specific content delivery, become dangerous when used to embed script tags or other malicious HTML elements within email messages. The vulnerability operates at the application layer where user input is not adequately validated or sanitized before being displayed in the web interface, creating a classic XSS attack vector that allows for session hijacking, credential theft, or redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple script execution to encompass potential full system compromise. When victims access infected email messages through the vulnerable SqWebMail interface, their browsers execute the injected scripts within the context of the web application's security domain. This presents attackers with opportunities to steal session cookies, capture user credentials, redirect users to phishing sites, or perform actions on behalf of authenticated users. The attack requires minimal user interaction beyond opening the malicious email message, making it particularly dangerous in corporate environments where users frequently access email through web interfaces. The vulnerability affects the web application's integrity and confidentiality, potentially allowing attackers to establish persistent access to email accounts and sensitive communications.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input sanitization and output encoding mechanisms. Organizations should immediately upgrade to a patched version of SqWebMail that properly validates and sanitizes all user-supplied content before rendering it in the web interface. The implementation of Content Security Policy headers can provide additional protection against script execution, while proper HTML escaping of all user input prevents malicious code from being interpreted as executable content. Security measures should also include regular security assessments of web applications to identify similar input validation flaws, with particular attention to legacy applications that may not have received recent security updates. Network-level protections such as email filtering systems can help prevent delivery of malicious emails containing conditional comments, though this approach is less reliable than application-level fixes. The vulnerability demonstrates the importance of secure coding practices and input validation, aligning with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment, where the initial compromise occurs through email-based attack vectors.