CVE-2018-6226 in Email Encryption Gateway
Summary
by MITRE
Reflected cross-site scripting (XSS) vulnerabilities in two Trend Micro Email Encryption Gateway 5.5 configuration files 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-2018-6226 represents a critical reflected cross-site scripting flaw within the Trend Micro Email Encryption Gateway 5.5 product line. This vulnerability manifests in two specific configuration files that fail to properly sanitize user input before processing it within the web interface. The affected system operates as an email encryption gateway that handles sensitive communications, making it a prime target for attackers seeking to exploit web application security weaknesses. The flaw occurs when the application reflects user-supplied data back to the browser without adequate validation or encoding, creating an environment where malicious scripts can execute within the context of authenticated users.
The technical implementation of this vulnerability stems from improper input validation mechanisms within the email gateway's web administration interface. When users interact with the configuration pages, the system processes parameters passed through HTTP requests without sufficient sanitization measures. This allows attackers to inject malicious JavaScript code through URL parameters or form inputs that are then reflected back to the victim's browser. The reflected nature of the vulnerability means that the malicious script does not need to be stored on the server, but rather executed directly from the attacker's payload when a victim accesses a specially crafted URL. This type of vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments or links.
The operational impact of this vulnerability extends beyond simple script execution, as it can potentially lead to complete session hijacking, credential theft, and unauthorized access to the email encryption gateway's administrative functions. An attacker who successfully exploits this vulnerability could gain access to sensitive email communications, modify encryption policies, or even redirect users to malicious sites that appear legitimate. The gateway's role in handling encrypted email communications makes this particularly dangerous, as compromised access could result in decryption of sensitive data or manipulation of security controls. Organizations using this product face significant risk of data breaches and regulatory compliance violations, especially in industries requiring strict email security measures such as healthcare, finance, or government sectors. The vulnerability's exploitation requires minimal technical skill and can be automated, making it attractive to both targeted attacks and broad scanning campaigns.
Mitigation strategies for CVE-2018-6226 should focus on immediate patch application from Trend Micro, as the vendor has released security updates addressing this specific flaw. Network segmentation and web application firewalls can provide additional protection layers to detect and block malicious payloads before they reach vulnerable endpoints. Input validation should be strengthened at all entry points, with proper encoding of output data to prevent script injection. Security monitoring should include detection of suspicious URL patterns and unusual administrative access patterns. Organizations should also implement regular security assessments and penetration testing to identify similar vulnerabilities in their email infrastructure. The vulnerability highlights the importance of maintaining up-to-date security patches and conducting thorough security reviews of email gateway configurations. Additional controls such as multi-factor authentication for administrative access and regular security training for system administrators can further reduce the risk of successful exploitation. Compliance with security standards such as NIST SP 800-53 and ISO 27001 should include specific controls addressing web application security and input validation to prevent similar vulnerabilities from occurring in the future.