CVE-2001-1159 in SquirrelMail
Summary
by MITRE
load_prefs.php and supporting include files in SquirrelMail 1.0.4 and earlier do not properly initialize certain PHP variables, which allows remote attackers to (1) view sensitive files via the config_php and data_dir options, and (2) execute arbitrary code by using options_order.php to upload a message that could be interpreted as PHP.
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Analysis
by VulDB Data Team • 09/27/2025
The vulnerability identified as CVE-2001-1159 represents a critical security flaw in SquirrelMail version 1.0.4 and earlier installations that stems from improper variable initialization within the load_prefs.php script and associated include files. This weakness falls under the broader category of insufficient variable initialization as classified by CWE-457, where variables are not properly initialized before use, creating potential security implications for applications that rely on these uninitialized values for configuration decisions. The vulnerability affects the core preference loading mechanism of the email client, which is fundamental to how user settings are processed and interpreted.
The technical exploitation of this vulnerability occurs through two distinct attack vectors that leverage the uninitialized PHP variables in different ways. The first vector allows remote attackers to read sensitive files by manipulating the config_php and data_dir options through the load_prefs.php script. This occurs because the application fails to properly validate or sanitize input parameters that control file paths, enabling attackers to traverse the file system and access configuration files or other sensitive data that should remain protected. The second and more dangerous vector involves the options_order.php file which permits attackers to upload messages that can be interpreted as PHP code, effectively creating a remote code execution vulnerability. This represents a classic case of insecure file handling and code injection that aligns with ATT&CK technique T1190 for exploitation of vulnerabilities in web applications.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass full system compromise potential. When attackers successfully exploit the uninitialized variable issue, they can gain access to sensitive configuration files that may contain database credentials, encryption keys, or other critical system information. The remote code execution capability transforms this into a severe threat that could allow attackers to establish persistent access, escalate privileges, or deploy additional malicious payloads within the compromised environment. This vulnerability directly impacts the confidentiality, integrity, and availability of the email service, as unauthorized parties can manipulate user preferences, access private communications, or potentially take complete control of the mail server.
Mitigation strategies for CVE-2001-1159 should prioritize immediate patching of affected SquirrelMail installations to version 1.0.5 or later, which contains the necessary fixes for variable initialization. Organizations should implement proper input validation and sanitization measures to prevent attackers from manipulating configuration parameters, particularly those that control file paths or execution contexts. Network segmentation and access controls should be enforced to limit exposure of the web application to untrusted networks. Additionally, regular security assessments and code reviews should be conducted to identify similar initialization issues in other applications, with particular attention to PHP applications that handle user-supplied input for configuration settings. The vulnerability serves as a reminder of the critical importance of proper variable initialization and input validation in preventing both information disclosure and code execution attacks, aligning with security best practices outlined in various industry standards including those from the Open Web Application Security Project and NIST guidelines for secure coding practices.