CVE-2013-6017 in Atmail
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Atmail Webmail Server before 7.2 allows remote attackers to inject arbitrary web script or HTML via the body of an e-mail message, as demonstrated by the SRC attribute of an IFRAME element.
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Analysis
by VulDB Data Team • 01/01/2025
The CVE-2013-6017 vulnerability represents a critical cross-site scripting flaw in the Atmail Webmail Server software prior to version 7.2, fundamentally compromising user security through improper input validation mechanisms. This vulnerability resides in the email message processing pipeline where the application fails to adequately sanitize user-supplied content before rendering it within web interfaces. The flaw specifically manifests when email messages containing malicious script code are processed and displayed to users, creating a persistent threat vector that can be exploited by remote attackers without requiring authentication or privileged access.
The technical implementation of this vulnerability stems from insufficient sanitization of email body content, particularly when processing iframe elements and their SRC attributes. Attackers can craft malicious email messages containing specially formatted iframe tags with malicious SRC values that execute arbitrary JavaScript code within the context of the victim's browser session. This occurs because the webmail server does not properly escape or filter user input before displaying it in web pages, allowing attackers to inject malicious payloads that persistently execute when users view compromised email messages. The vulnerability is classified as a classic stored XSS attack where the malicious code is stored on the server and executed whenever the affected page is accessed.
The operational impact of CVE-2013-6017 extends beyond simple script injection, creating a comprehensive attack surface that enables various malicious activities including session hijacking, credential theft, and redirection to malicious domains. When users access compromised email messages, their browsers execute the injected scripts, potentially leading to full account compromise, data exfiltration, or lateral movement within organizational networks. The vulnerability affects the core functionality of the webmail interface, making it a high-risk issue that can be exploited at scale, particularly in environments where users frequently access email through web interfaces. This type of vulnerability directly aligns with CWE-79, which describes improper neutralization of input during web page generation, and maps to ATT&CK technique T1566 for initial access through spearphishing with malicious attachments or links.
Mitigation strategies for this vulnerability require immediate application of security patches to update Atmail Webmail Server to version 7.2 or later, which includes proper input sanitization and output encoding mechanisms. Organizations should implement comprehensive email filtering solutions that can detect and block suspicious content, including malformed iframe elements and other XSS vectors. Network-level protections such as web application firewalls and content security policies should be deployed to add additional layers of defense. Additionally, user education programs should emphasize the importance of not clicking on suspicious links or opening untrusted email attachments, while administrators should regularly audit email content and monitor for unusual access patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and output encoding in web applications, particularly those handling user-generated content, and serves as a reminder of the necessity for robust security practices throughout the software development lifecycle.