CVE-2006-0091 in Open-Xchange
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in webmail in Open-Xchange 0.8.1-6 and earlier, with "Inline HTML" enabled, allows remote attackers to inject arbitrary web script or HTML via e-mail attachments, which are rendered inline.
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Analysis
by VulDB Data Team • 01/11/2019
The vulnerability described in CVE-2006-0091 represents a critical cross-site scripting flaw within the Open-Xchange webmail system, specifically affecting versions 0.8.1-6 and earlier. This vulnerability exploits the system's handling of email attachments when the "Inline HTML" rendering feature is enabled, creating a pathway for malicious actors to execute arbitrary web scripts or HTML code within the context of authenticated user sessions. The flaw resides in the webmail application's insufficient input validation and output encoding mechanisms when processing email content that contains HTML elements, particularly those embedded within attachments.
The technical implementation of this vulnerability stems from the application's failure to properly sanitize user-supplied content before rendering it inline within the web interface. When users receive emails with HTML attachments or embedded HTML content, the Open-Xchange system processes these elements without adequate filtering or encoding, allowing malicious scripts to be executed in the browser context of the victim. This represents a classic server-side XSS vulnerability where the malicious payload is stored in the application's database and subsequently served to other users who view the affected email content. The vulnerability operates under CWE-79 which specifically addresses Cross-site Scripting flaws, and aligns with ATT&CK technique T1566.001 for Initial Access through Spearphishing Attachments.
The operational impact of this vulnerability is significant as it enables remote attackers to compromise user sessions and potentially escalate privileges within the webmail environment. An attacker could craft malicious email attachments containing embedded scripts that execute when users view the emails, potentially stealing session cookies, redirecting users to malicious sites, or performing unauthorized actions on behalf of the victim. The threat is particularly concerning because it leverages legitimate email functionality and does not require direct user interaction beyond viewing the affected email content. This vulnerability can be exploited to conduct session hijacking attacks, data exfiltration, or serve as a foothold for further attacks within the organization's network infrastructure.
Mitigation strategies for this vulnerability should include immediate patching of the Open-Xchange system to versions that address the XSS flaw, implementing strict input validation for all email content including attachments, and disabling inline HTML rendering where possible. Organizations should also consider implementing Content Security Policy headers to prevent execution of unauthorized scripts, and establish robust email filtering mechanisms to detect and quarantine suspicious attachments. The remediation approach should follow security best practices outlined in NIST SP 800-171 and ISO 27001 standards for secure application development, ensuring proper input sanitization and output encoding mechanisms are implemented to prevent similar vulnerabilities in future deployments. Additionally, user education regarding the dangers of opening suspicious email attachments remains critical in reducing the attack surface for this type of vulnerability.