CVE-2024-9103 in Email Security
Summary
by MITRE • 03/24/2025
Improper Neutralization of Script in Attributes in a Web Page vulnerability in Forcepoint Email Security (Blocked Messages module) allows Stored XSS. This issue affects Email Security through 8.5.5.
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Analysis
by VulDB Data Team • 03/24/2025
The CVE-2024-9103 vulnerability represents a critical security flaw in Forcepoint Email Security's Blocked Messages module that enables stored cross-site scripting attacks through improper neutralization of script content within HTML attributes. This vulnerability specifically impacts versions of the Email Security platform up to and including 8.5.5, creating a significant risk for organizations that rely on this security solution for email protection and content filtering. The flaw resides in how the system processes and displays blocked email messages, particularly in the attribute handling mechanisms that fail to properly sanitize user-controllable input before rendering it within web interfaces.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding practices within the Blocked Messages module. When email messages are blocked and subsequently displayed in the web interface, the system fails to properly escape or neutralize potentially malicious script content that may be present in message attributes such as headers, subject lines, or other metadata fields. This improper handling creates an environment where attacker-controlled content can be injected into HTML attributes without proper sanitization, allowing malicious scripts to execute within the context of a user's browser session. The vulnerability specifically manifests when the system renders blocked message details in web pages where script content can be interpreted as executable code rather than plain text.
The operational impact of this vulnerability extends beyond simple data exposure, as it enables attackers to perform a range of malicious activities through the compromised web interface. An attacker who can influence the content of blocked messages or manipulate the system's message handling process can inject persistent script payloads that will execute whenever legitimate users view the blocked messages. This stored XSS capability allows for session hijacking, credential theft, redirection to malicious sites, and potential privilege escalation within the email security platform. The vulnerability affects the integrity and confidentiality of email security operations, potentially enabling attackers to bypass security controls and gain unauthorized access to email content or system management functions.
Organizations affected by this vulnerability should prioritize immediate remediation through the application of Forcepoint's official security patches or updates addressing this specific XSS flaw. The mitigation strategy should include comprehensive input validation and output encoding measures that align with established security frameworks such as CWE-79, which specifically addresses cross-site scripting vulnerabilities through improper neutralization of input. Additionally, implementing proper web application firewall rules, content security policies, and regular security assessments can help reduce the attack surface and prevent exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1566.001 technique for initial access through spearphishing attachments, making it particularly dangerous when combined with social engineering campaigns that target email security administrators or users who regularly access blocked message interfaces. Organizations should also consider implementing network segmentation and monitoring solutions to detect anomalous behavior patterns that may indicate exploitation attempts, while maintaining regular vulnerability assessments to identify similar issues in other security components and web applications.