CVE-2007-5654 in LiteSpeed Web Server
Summary
by MITRE
LiteSpeed Web Server before 3.2.4 allows remote attackers to trigger use of an arbitrary MIME type for a file via a "%00." sequence followed by a new extension, as demonstrated by reading PHP source code via requests for .php%00.txt files, aka "Mime Type Injection."
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Analysis
by VulDB Data Team • 10/08/2024
The CVE-2007-5654 vulnerability represents a critical mime type injection flaw in LiteSpeed Web Server versions prior to 3.2.4 that enables remote attackers to manipulate file handling behavior through crafted file extensions. This vulnerability specifically exploits how the web server processes file names containing null byte sequences followed by alternative extensions, creating a path for unauthorized code execution and information disclosure. The flaw occurs at the file extension parsing level where the server fails to properly sanitize input containing null characters, allowing attackers to bypass normal file type validation mechanisms.
The technical implementation of this vulnerability relies on the manipulation of file name parsing logic within LiteSpeed Web Server's content delivery system. When a request is made for a file such as .php%00.txt, the web server's internal parsing routine interprets the null byte as a delimiter, causing the system to treat the file as having the extension following the null character rather than the original extension. This behavior creates a scenario where a .php file could be served with a text/plain mime type instead of application/php, effectively allowing attackers to execute php code through a text file handler or to read php source code as plain text, depending on the specific configuration and the target file type.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential code execution capabilities and unauthorized access to sensitive server resources. Attackers can leverage this flaw to read php source code files, potentially exposing database credentials, application logic, and other sensitive information contained within the source files. The vulnerability is particularly dangerous because it allows attackers to bypass normal security controls that would typically prevent execution of php files, effectively creating a backdoor mechanism for accessing server-side code. This issue directly relates to CWE-1287, which addresses improper handling of null bytes in file name processing, and aligns with ATT&CK technique T1566.001 for initial access through malicious file uploads.
Mitigation strategies for CVE-2007-5654 require immediate patching of LiteSpeed Web Server installations to version 3.2.4 or later, which contains the necessary fixes for proper null byte handling in file name parsing. Organizations should also implement additional security controls such as restricting file upload capabilities, implementing proper input validation for file names, and configuring web servers to reject requests containing null bytes in file paths. Network-level protections including web application firewalls and intrusion detection systems can help detect and block malicious requests containing null byte sequences. System administrators should conduct thorough security assessments of all web server configurations to identify any other potential injection vectors and ensure that file handling routines properly sanitize all input parameters. The vulnerability demonstrates the importance of proper input validation and the potential consequences of inadequate null byte handling in web server implementations, making it a critical consideration for any organization relying on web server software for hosting applications.