CVE-2008-5734 in Merak Mail Server
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in WebMail Pro in IceWarp Software Merak Mail Server 9.3.2 allows remote attackers to inject arbitrary web script or HTML via an IMG element in an HTML e-mail message.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/23/2019
The vulnerability identified as CVE-2008-5734 represents a critical cross-site scripting flaw within the WebMail Pro component of IceWarp Software's Merak Mail Server version 9.3.2. This security weakness specifically targets the email rendering functionality where user-generated content from HTML email messages is processed and displayed within the web-based mail interface. The flaw arises from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before it is rendered in the browser context. Attackers can exploit this vulnerability by crafting malicious email messages containing specially formatted IMG elements that execute arbitrary JavaScript code or HTML content when viewed by unsuspecting users within the vulnerable webmail environment.
The technical exploitation of this vulnerability occurs through the improper handling of HTML content within email messages that are displayed in the WebMail Pro interface. When a user opens an email containing an IMG element with malicious attributes or source URLs, the web application fails to properly escape or filter the embedded HTML code. This allows attackers to inject script tags, malicious URLs, or other harmful content that executes within the context of the user's browser session. The vulnerability specifically leverages the IMG element because it can contain JavaScript event handlers such as onclick, onerror, or onload attributes that trigger malicious code execution when the image is processed or displayed. The flaw exists in the server-side rendering logic that does not adequately distinguish between legitimate and malicious HTML content, creating an environment where user input directly influences the output rendered to web browsers.
The operational impact of this vulnerability extends beyond simple script execution to potentially enable sophisticated attack vectors including session hijacking, credential theft, and data exfiltration. An attacker who successfully compromises a user's browser through this XSS vulnerability can access the user's email account, read sensitive messages, send emails on behalf of the victim, and potentially escalate privileges within the mail server environment. The attack surface is particularly concerning given that email remains one of the primary attack vectors for enterprise security breaches, and the Merak Mail Server serves as a critical communication infrastructure for many organizations. The vulnerability affects not only individual users but also organizational security posture, as successful exploitation could lead to unauthorized access to sensitive corporate communications, intellectual property, and personal data. This type of vulnerability is particularly dangerous in environments where users may not be security-aware and may inadvertently click on malicious links or attachments within email messages.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding mechanisms within the WebMail Pro application. Organizations should immediately apply the vendor-provided security patches or updates that address this specific XSS vulnerability. The remediation approach should include implementing strict HTML sanitization routines that remove or escape dangerous elements and attributes from user-supplied content before rendering. Security controls should be designed to follow the principle of least privilege, ensuring that email content is processed with minimal permissions and that no user input is directly executed as code. Additionally, organizations should deploy web application firewalls and content security policies that can detect and block malicious script execution attempts. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and it maps to ATT&CK technique T1566 which covers social engineering through email. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the mail server infrastructure, while user education programs should emphasize the importance of not clicking on suspicious links or opening unexpected email attachments. Organizations should also consider implementing email security gateways that can detect and block malicious HTML content before it reaches the vulnerable webmail interface, providing an additional layer of defense against such attacks.