CVE-2023-39699 in Mail Server
Summary
by MITRE • 08/25/2023
IceWarp Mail Server v10.4.5 was discovered to contain a local file inclusion (LFI) vulnerability via the component /calendar/minimizer/index.php. This vulnerability allows attackers to include or execute files from the local file system of the targeted server.
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Analysis
by VulDB Data Team • 01/25/2026
The CVE-2023-39699 vulnerability represents a critical local file inclusion flaw within the IceWarp Mail Server version 10.4.5 that specifically targets the calendar minimizer component. This vulnerability exists in the /calendar/minimizer/index.php file and provides attackers with the capability to execute arbitrary file inclusion attacks against the underlying server filesystem. The flaw stems from inadequate input validation and sanitization within the calendar module, allowing malicious actors to manipulate file path parameters and gain unauthorized access to sensitive system files. Such vulnerabilities typically arise when applications fail to properly validate user-supplied input before using it in file operations, creating a direct pathway for attackers to traverse the filesystem and potentially execute malicious code.
The technical exploitation of this LFI vulnerability follows established patterns that align with CWE-98, which specifically addresses the inclusion of files without proper validation of the file path. Attackers can leverage this weakness by crafting malicious requests that manipulate the parameters used in the minimizer component to include local files such as configuration files, database credentials, or system binaries. The operational impact extends beyond simple information disclosure, as successful exploitation can lead to complete system compromise through the execution of arbitrary code or the retrieval of sensitive data. This vulnerability particularly affects organizations relying on IceWarp Mail Server for their email infrastructure, potentially exposing critical business communications and user data to unauthorized access.
The security implications of CVE-2023-39699 align with several ATT&CK framework techniques including T1566 for credential access through file system access and T1059 for command and script execution. Organizations utilizing this mail server version face significant risk of data breaches, as attackers can potentially extract database connection strings, user credentials, and other sensitive information stored within the server's file system. The vulnerability's impact is amplified by the fact that it exists in a core calendar component, which is frequently accessed by legitimate users, making exploitation more likely and harder to detect. Network defenders should consider implementing web application firewalls and input validation rules to prevent malicious path traversal attempts.
Mitigation strategies for this vulnerability should include immediate patching of the IceWarp Mail Server to version 10.4.6 or later, which addresses the LFI flaw through proper input validation and sanitization. System administrators should also implement network segmentation to limit access to the calendar component and monitor for suspicious file access patterns. Additional protective measures include disabling unnecessary file inclusion features, implementing strict input validation at all application entry points, and conducting regular security assessments of web applications. Organizations should also establish proper access controls and monitoring of system files to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and the potential for seemingly minor flaws to result in significant security breaches when exploited by skilled attackers.