CVE-2005-4557 in Mail Server
Summary
by MITRE
dir/include.html in IceWarp Web Mail 5.5.1, as used by Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1, allows remote attackers to include arbitrary local files via a null byte (%00) in the lang parameter, possibly due to a directory traversal vulnerability.
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Analysis
by VulDB Data Team • 07/28/2025
The vulnerability described in CVE-2005-4557 represents a critical directory traversal flaw affecting IceWarp Web Mail version 5.5.1 when integrated with Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1. This security weakness resides in the dir/include.html component where the application fails to properly validate user input parameters, specifically the lang parameter that controls language localization settings. The flaw enables remote attackers to manipulate the application's file inclusion mechanism by inserting a null byte character sequence %00 into the lang parameter, effectively bypassing normal input validation checks and allowing arbitrary local file access.
The technical exploitation of this vulnerability stems from improper input sanitization and validation within the web application's language selection functionality. When the application processes the lang parameter, it does not adequately filter or sanitize the input to prevent directory traversal sequences or null byte injection attacks. This allows attackers to craft malicious requests that can traverse the file system and access sensitive local files that should remain protected from external access. The null byte injection technique exploits a weakness in how the application handles string termination, where the %00 sequence effectively terminates the string processing and allows subsequent path traversal components to be interpreted as part of the file path rather than as separate parameters.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with unauthorized access to the underlying file system of the affected mail servers. Successful exploitation could lead to disclosure of sensitive configuration files, user credentials, email data, and potentially system-level information that could be used for further attacks. The vulnerability affects not just the web mail interface but the entire mail server infrastructure that relies on this component, making it a critical concern for organizations using these specific server versions. The remote nature of the attack means that adversaries do not need physical access to the system or local network privileges to exploit this weakness, making it particularly dangerous in networked environments.
Security professionals should note that this vulnerability aligns with CWE-22 Directory Traversal and CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component, as it represents a classic path traversal attack combined with improper input handling. The attack vector maps to techniques documented in the MITRE ATT&CK framework under T1059 Command and Scripting Interpreter and T1566 Phishing, as attackers could leverage this vulnerability to gain system access and potentially establish persistent access through the stolen credentials or system information. Organizations should immediately apply vendor patches or updates to address this vulnerability, implement network segmentation to limit access to mail server components, and conduct thorough security assessments of their mail server configurations to identify any similar input validation weaknesses that might exist in other components of their email infrastructure.