CVE-2018-6227 in Email Encryption Gateway
Summary
by MITRE
A stored cross-site scripting (XSS) vulnerability in Trend Micro Email Encryption Gateway 5.5 could allow an attacker to inject client-side scripts into vulnerable systems.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2018-6227 represents a critical stored cross-site scripting flaw within Trend Micro Email Encryption Gateway version 5.5. This security weakness resides in the email gateway's handling of user input and its subsequent rendering within web interfaces, creating an environment where malicious actors can persistently inject client-side scripts that execute in the context of other users' browsers. The vulnerability specifically affects the email encryption gateway's web administration interface, where unvalidated input parameters are processed and displayed without proper sanitization mechanisms. Attackers can exploit this flaw by crafting malicious payloads that get stored on the server and subsequently executed when other users access affected pages, making it particularly dangerous for environments where multiple administrators or users interact with the same management interface.
The technical implementation of this stored XSS vulnerability stems from inadequate input validation and output encoding practices within the Trend Micro Email Encryption Gateway's web application layer. When user-supplied data is accepted through various input vectors such as configuration parameters, user names, or email addresses, the application fails to properly sanitize this data before incorporating it into dynamic web content. This weakness allows attackers to inject malicious JavaScript code that persists in the application's database or configuration files. The flaw manifests when the application retrieves and displays this tainted data without appropriate HTML escaping or context-specific encoding, enabling the injected scripts to execute in the browser context of legitimate users who access affected pages. The vulnerability is classified as CWE-79, which specifically addresses cross-site scripting flaws in web applications.
The operational impact of CVE-2018-6227 extends beyond simple data theft or session hijacking, as it provides attackers with the capability to establish persistent footholds within email security infrastructure. Once exploited, the vulnerability allows attackers to execute arbitrary code in the browser context of authenticated users, potentially enabling them to access sensitive email encryption configurations, view encrypted messages, or manipulate the email gateway's administrative functions. The stored nature of this vulnerability means that the malicious payloads remain active even after the initial injection, continuously affecting any user who accesses the affected web interface. This persistent threat could lead to extended reconnaissance activities, data exfiltration, or the establishment of backdoor access points within the email security infrastructure, particularly concerning environments where the email gateway serves as a critical component of enterprise security posture. The vulnerability affects organizations that rely on Trend Micro's email encryption solutions for protecting sensitive communications, potentially compromising the integrity and confidentiality of their email security operations.
Organizations affected by CVE-2018-6227 should implement immediate mitigations including applying the vendor-provided security patches and updates released by Trend Micro to address the XSS vulnerability. Network segmentation and access controls should be strengthened to limit exposure of the email gateway's web administration interface to only authorized personnel, while implementing web application firewalls to detect and block malicious payload attempts. Regular security audits and input validation reviews should be conducted to identify similar vulnerabilities in other web applications within the organization's infrastructure. Additionally, administrators should implement monitoring solutions to detect unusual activities in the email gateway's web interface and establish incident response procedures specifically tailored to address potential XSS exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date security measures and proper input validation practices, aligning with ATT&CK technique T1059.007 for scripting and T1566.001 for spearphishing with attachments, which are commonly used to exploit such web application vulnerabilities. Organizations should also consider implementing security awareness training for administrators to recognize potential social engineering attempts that might leverage this vulnerability to gain initial access to the email encryption gateway.