CVE-2007-0975 in Apache Stats
Summary
by MITRE
Variable extraction vulnerability in Ian Bezanson Apache Stats before 0.0.3 beta allows attackers to overwrite critical variables, with unknown impact, when the extract function is used on the _REQUEST superglobal array.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/13/2017
The vulnerability identified as CVE-2007-0975 represents a critical variable extraction flaw in Ian Bezanson Apache Stats version 0.0.2 and earlier, which falls under the category of insecure direct object reference and improper input handling within web applications. This vulnerability specifically targets the use of the extract function in php applications, where the function processes the _REQUEST superglobal array without proper sanitization or validation. The flaw enables attackers to manipulate variable names and values during the extraction process, potentially allowing them to overwrite critical system variables or application configuration parameters that are essential for proper application operation. This type of vulnerability is particularly dangerous because it can lead to arbitrary code execution or complete system compromise when attackers leverage the ability to modify variables that control application behavior. The vulnerability stems from the improper handling of user-supplied input within the context of php's variable extraction mechanisms, which should never be used with untrusted data sources without proper validation and sanitization.
The technical implementation of this vulnerability occurs when the extract function is invoked on the _REQUEST superglobal array, which contains data from GET, POST, and COOKIE parameters. This function automatically creates variables from array keys, making it possible for an attacker to inject malicious variable names that correspond to critical application variables. When the extract function processes user-controlled input from _REQUEST, it creates variables in the current symbol table without proper filtering, allowing attackers to overwrite variables such as configuration settings, authentication tokens, or other critical application state variables. The vulnerability is classified as a CWE-20: Improper Input Validation and CWE-94: Improper Control of Generation of Code, which directly relates to the dangerous practice of executing code or creating variables from untrusted input sources. This flaw is particularly concerning because it allows attackers to manipulate application logic by overwriting variables that control program flow, authentication checks, or data processing routines, potentially leading to unauthorized access or data manipulation.
The operational impact of this vulnerability extends beyond simple data corruption or unauthorized access to include potential complete system compromise, as demonstrated by the lack of known impact specification in the original CVE description. Attackers can exploit this vulnerability to overwrite critical application variables that control authentication mechanisms, database connection parameters, or file access controls, potentially allowing them to execute arbitrary code on the target system. The vulnerability's exploitation requires minimal technical knowledge and can be automated, making it particularly dangerous for web applications that process user input through the _REQUEST superglobal array. This type of vulnerability aligns with ATT&CK technique T1190: Exploit Public-Facing Application, where adversaries target web applications for initial access or privilege escalation. The vulnerability's impact is amplified by the fact that many applications rely on the extract function for convenience in processing form data, but fail to implement proper input validation or sanitization, creating a widespread attack surface that affects numerous applications using similar patterns.
Mitigation strategies for CVE-2007-0975 require immediate implementation of secure coding practices and comprehensive input validation. The most effective approach involves avoiding the use of the extract function with untrusted input sources entirely, or at minimum implementing strict parameter validation and filtering before any extraction occurs. Applications should utilize explicit variable assignment instead of automatic extraction, ensuring that only expected and validated variables are processed. Additionally, developers should implement proper input sanitization techniques and employ parameterized queries or prepared statements when dealing with user input. Security measures should include regular code reviews focusing on variable extraction patterns and input handling practices, as well as implementing proper access controls and authentication mechanisms to limit the potential impact of successful exploitation. Organizations should also consider implementing web application firewalls and runtime monitoring to detect and prevent exploitation attempts. The vulnerability highlights the importance of following secure coding guidelines and adhering to the principle of least privilege when processing user input, as well as maintaining up-to-date application versions to avoid known vulnerabilities that have been addressed in newer releases.