CVE-2005-4559 in Mail Server
Summary
by MITRE
mail/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, does not properly initialize the default_layout and layout_settings variables when an unrecognized HTTP_USER_AGENT string is provided, which allows remote attackers to access arbitrary files via a request with an unrecognized User Agent that also specifies the desired default_layout and layout_settings parameters.
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Analysis
by VulDB Data Team • 07/28/2025
The vulnerability identified as CVE-2005-4559 represents a critical security flaw within the IceWarp Web Mail 5.5.1 component when integrated with Merak Mail Server 8.3.0r and VisNetic Mail Server version 8.3.0 build 1. This issue stems from improper initialization of critical variables within the mail/include.html file, specifically the default_layout and layout_settings parameters. The vulnerability manifests when the web application encounters an unrecognized HTTP_USER_AGENT string, creating a scenario where attackers can manipulate the application's behavior through crafted HTTP requests. This flaw operates at the intersection of input validation and variable initialization, creating a path for unauthorized file access that bypasses normal security controls.
The technical implementation of this vulnerability exploits a classic variable initialization flaw that falls under CWE-457, which describes the use of uninitialized variables in software applications. When the web server processes a request with an unrecognized User Agent, the application fails to properly initialize the default_layout and layout_settings variables, leaving them in an undefined state. Attackers can leverage this undefined behavior by crafting HTTP requests that include specific parameters within the User Agent string, effectively manipulating the application's internal state to access arbitrary files on the server. The vulnerability demonstrates how improper input handling can lead to privilege escalation and information disclosure, as the application's file access controls become bypassed through manipulation of the HTTP_USER_AGENT header.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables remote attackers to potentially access sensitive server files including configuration data, user credentials, and system information. This represents a significant risk to organizations relying on these mail server implementations, particularly given the age of the affected software versions. The vulnerability can be exploited without authentication, making it particularly dangerous as it allows attackers to probe the server's file system and potentially discover additional attack vectors. The flaw affects not just the mail server functionality but can also provide attackers with insights into the underlying server architecture and file permissions, supporting further exploitation attempts.
Security mitigations for this vulnerability should focus on implementing proper input validation and variable initialization practices within the affected application components. Organizations should immediately patch the vulnerable software versions or implement web application firewalls that can detect and block suspicious User Agent patterns. The remediation process should include ensuring that all variables are properly initialized before use, implementing strict input validation for HTTP_USER_AGENT headers, and applying principle of least privilege access controls to file system resources. Additionally, monitoring for unusual User Agent patterns and implementing intrusion detection systems can help identify exploitation attempts. This vulnerability aligns with ATT&CK technique T1059, which covers command and scripting interpreter usage, as attackers may leverage the file access capabilities to execute malicious payloads or gather intelligence for further attacks. The issue also reflects broader concerns about legacy software security where outdated applications continue to pose significant risks to organizational security postures.