CVE-2006-6364 in Inside Systems
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in error.php in Inside Systems Mail (ISMail) 2.0 and earlier allows remote attackers to inject arbitrary web script or HTML via the error parameter.
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Analysis
by VulDB Data Team • 11/28/2025
The CVE-2006-6364 vulnerability represents a classic cross-site scripting flaw in the Inside Systems Mail version 2.0 and earlier products. This vulnerability exists within the error.php script which handles error reporting functionality within the email system. The flaw manifests when the application fails to properly sanitize user input passed through the error parameter, creating an avenue for malicious actors to inject arbitrary web scripts or HTML code into the application's response. The vulnerability is particularly concerning as it operates at the application layer where user-supplied data is directly incorporated into web responses without adequate validation or encoding mechanisms.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding practices within the ISMail error handling mechanism. When the error parameter is processed by error.php, the application does not adequately filter or escape special characters that could be interpreted as HTML or JavaScript code by web browsers. This allows attackers to craft malicious payloads that, when executed in the context of a victim's browser, can perform unauthorized actions such as stealing session cookies, redirecting users to malicious sites, or defacing web pages. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, and demonstrates poor application security practices that violate fundamental secure coding principles.
Operationally, this vulnerability presents significant risks to organizations using ISMail versions 2.0 or earlier. Attackers can exploit this flaw to execute malicious scripts in the context of authenticated users, potentially leading to complete account compromise, data exfiltration, or unauthorized access to email communications. The remote nature of the attack means that threat actors do not require physical access to the system or knowledge of valid credentials to exploit the vulnerability. This makes the flaw particularly dangerous in environments where email systems handle sensitive corporate or personal information, as it could enable attackers to establish persistent access to email accounts and potentially escalate privileges within the network. The vulnerability also aligns with ATT&CK technique T1566 which covers social engineering tactics involving the delivery of malicious code through web-based attacks.
Mitigation strategies for CVE-2006-6364 should focus on immediate remediation through software updates to newer versions of ISMail that address the input validation issues. Organizations should implement proper input sanitization measures including the use of allowlists for valid characters, comprehensive output encoding for all user-supplied data, and the implementation of Content Security Policy headers to limit script execution. Additionally, web application firewalls should be configured to detect and block suspicious input patterns, while regular security audits should verify that all user input is properly validated before being processed or displayed. The vulnerability underscores the importance of maintaining current software versions and implementing robust security controls as outlined in industry standards such as the OWASP Top Ten and NIST cybersecurity guidelines.