CVE-2018-14952 in SquirrelMail
Summary
by MITRE
The mail message display page in SquirrelMail through 1.4.22 has XSS via a "<math><maction xlink:href=" attack.
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Analysis
by VulDB Data Team • 04/29/2023
The vulnerability CVE-2018-14952 represents a cross-site scripting flaw discovered in SquirrelMail version 1.4.22 and earlier, affecting the mail message display functionality. This vulnerability specifically targets the rendering of HTML content within email messages, creating a potential attack vector that could be exploited by malicious actors to execute arbitrary JavaScript code in the context of a victim's browser. The flaw manifests when the application processes email messages containing specially crafted mathematical markup elements that leverage the xlink:href attribute to redirect or execute malicious payloads.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within SquirrelMail's message display component. When the application encounters a message containing a "<math><maction xlink:href=" construct, it fails to properly escape or filter the xlink:href attribute, allowing attackers to inject malicious URLs that can redirect users to malicious sites or execute JavaScript code. This particular attack vector exploits the MathML specification's support for hyperlinking through the xlink:href attribute, which is not adequately handled by the application's security controls. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws resulting from improper sanitization of user-controllable data.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal user credentials, redirect victims to phishing sites, or execute additional malicious payloads. An attacker could craft an email message containing the malicious MathML construct and send it to a victim who is using SquirrelMail, potentially compromising the victim's session and access to their email account. This vulnerability particularly affects web-based email clients where users trust the content of received messages, making it a significant concern for organizations relying on SquirrelMail for email communication. The attack requires minimal user interaction beyond reading the malicious email, making it particularly dangerous in enterprise environments where email is a primary communication channel.
Organizations should immediately update their SquirrelMail installations to version 1.4.23 or later, which includes patches addressing this vulnerability. System administrators should also implement additional security measures such as content security policies that restrict the execution of inline scripts and external resource loading. Network-based protections including web application firewalls and email filtering systems can provide additional layers of defense by detecting and blocking malicious MathML constructs before they reach end users. The vulnerability demonstrates the importance of proper input validation for all user-controllable data, particularly in web applications that render third-party content, and aligns with ATT&CK technique T1203 for "Exploitation for Client Execution" where attackers leverage web-based vulnerabilities to execute malicious code in user browsers.