CVE-2017-11617 in Atmail
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in atmail prior to version 7.8.0.2 allows remote attackers to inject arbitrary web script or HTML within the body of an email via an IMG element with both single quotes and double quotes.
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Analysis
by VulDB Data Team • 11/01/2019
The CVE-2017-11617 vulnerability represents a critical cross-site scripting flaw in the atmail email platform that affected versions prior to 7.8.0.2. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is one of the most prevalent and dangerous web application security flaws. The vulnerability specifically manifests when the application fails to properly sanitize user-supplied input within email content, creating an avenue for malicious actors to execute arbitrary JavaScript code in the context of a victim's browser session. The flaw is particularly concerning because it allows attackers to inject malicious code directly into email messages through the IMG element, leveraging both single and double quote characters to bypass standard input validation mechanisms.
The technical exploitation of this vulnerability occurs when atmail processes email messages containing malicious IMG tags with embedded JavaScript payloads. Attackers can craft email content that includes an IMG element with a src attribute containing malicious JavaScript code, using both single and double quotes to ensure the payload executes successfully across different browser environments. The vulnerability exists because the application's input sanitization process does not adequately filter or escape special characters, particularly those used in HTML and JavaScript contexts. This allows the malicious code to be stored within the email system and subsequently executed when unsuspecting users view the affected email messages, creating a persistent threat vector that can compromise user sessions and potentially exfiltrate sensitive information.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable sophisticated attack vectors including session hijacking, credential theft, and redirection to malicious websites. When users access compromised email messages, their browsers execute the injected scripts within the context of the atmail application's domain, potentially allowing attackers to steal session cookies, modify email content, or redirect users to phishing sites. The vulnerability affects the core functionality of email processing and rendering, making it particularly dangerous for organizations that rely heavily on email communication for business operations. Security researchers have noted that this type of vulnerability can be exploited in phishing campaigns, where attackers craft emails that appear legitimate but contain hidden malicious payloads that activate when users open the messages.
Organizations affected by this vulnerability should implement immediate mitigations including updating to atmail version 7.8.0.2 or later, which contains the necessary patches to address the input sanitization flaws. Additionally, administrators should implement strict email content filtering policies that scan for suspicious HTML elements and JavaScript code within email messages. The implementation of Content Security Policy headers can provide an additional layer of protection by restricting the sources from which scripts can be loaded within the application context. Network-level security controls such as email gateway filtering and web application firewalls can also help detect and prevent exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command and control communications and credential access, as attackers can leverage the XSS to establish persistent access to user accounts and extract sensitive information from compromised sessions. Regular security assessments and input validation testing should be conducted to ensure that similar vulnerabilities are not present in other application components.