CVE-2017-15890 in MailPlus Server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Disclaimer in Synology MailPlus Server before 1.4.0-0415 allows remote authenticated users to inject arbitrary web script or HTML via the NAME parameter.
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Analysis
by VulDB Data Team • 01/18/2023
The vulnerability identified as CVE-2017-15890 represents a critical cross-site scripting flaw within the Disclaimer component of Synology MailPlus Server versions prior to 1.4.0-0415. This issue affects remote authenticated users who can exploit the vulnerability by injecting malicious web script or HTML content through the NAME parameter, potentially compromising the security of the email server environment. The flaw resides in the improper validation and sanitization of user input within the disclaimer functionality, creating a persistent vector for malicious code execution.
The technical implementation of this vulnerability stems from inadequate input filtering mechanisms within the MailPlus Server's disclaimer module. When authenticated users submit data through the NAME parameter, the system fails to properly sanitize or escape special characters that could be interpreted as executable script code. This allows attackers to inject malicious payloads that execute in the context of other users' browsers who view the affected disclaimer content. The vulnerability specifically affects the server-side processing of user-provided data within the disclaimer feature, making it particularly dangerous as it operates within a trusted administrative context where users have legitimate access to the system.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform a range of malicious activities including session hijacking, credential theft, and redirection to malicious websites. Remote authenticated users with access to the MailPlus Server can leverage this vulnerability to compromise the confidentiality and integrity of email communications within the organization. The attack vector is particularly concerning because it requires only legitimate user credentials to exploit, making it difficult to detect and prevent through traditional network monitoring approaches. This vulnerability can facilitate further attacks within the network by allowing attackers to gain access to sensitive email data and potentially escalate privileges within the email infrastructure.
Mitigation strategies for CVE-2017-15890 should prioritize immediate patching of affected MailPlus Server installations to version 1.4.0-0415 or later, which contains the necessary input validation fixes. Organizations should implement additional security measures including regular input validation testing, web application firewalls, and enhanced monitoring of user activity within the email server environment. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and maps to ATT&CK technique T1566.001 for initial access through spearphishing attachments or links. Security teams should also consider implementing strict input sanitization policies and regular security assessments to prevent similar vulnerabilities in other components of the email infrastructure.