CVE-2001-1370 in PHPLib
Summary
by MITRE
prepend.php3 in PHPLib before 7.2d, when register_globals is enabled for PHP, allows remote attackers to execute arbitrary scripts via an HTTP request that modifies $_PHPLIB[libdir] to point to malicious code on another server, as seen in Horde 1.2.5 and earlier, IMP before 2.2.6, and other packages that use PHPLib.
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Analysis
by VulDB Data Team • 12/30/2024
The vulnerability described in CVE-2001-1370 represents a classic remote code execution flaw that emerged during the early php era when security practices were less mature. This issue specifically targets PHPLib versions prior to 7.2d and exploits a dangerous configuration setting known as register_globals being enabled. The vulnerability operates through a sophisticated manipulation of PHP's superglobal variables, particularly the $_PHPLIB[libdir] parameter that controls library directory paths. When register_globals is enabled, PHP automatically creates global variables from HTTP request parameters, creating a dangerous attack surface where malicious actors can influence the application's behavior by injecting crafted parameters into HTTP requests. The flaw becomes particularly dangerous when combined with the way PHPLib handles library paths, as it allows attackers to redirect the application's library loading mechanism to point to malicious code hosted on external servers.
The technical exploitation mechanism relies on the insecure handling of the libdir configuration parameter within PHPLib's prepend.php3 file. This file serves as a critical initialization component that loads various library functions, and when register_globals is enabled, an attacker can manipulate the $_PHPLIB[libdir] variable through HTTP GET or POST parameters. The vulnerability demonstrates a clear path to privilege escalation and system compromise, as the attacker's malicious code can be executed in the context of the web server process, potentially leading to full system control. The attack vector specifically leverages the trust model where the application assumes that the libdir parameter will always point to legitimate library files, without proper validation or sanitization of external inputs. This flaw directly relates to CWE-94, which describes the weakness of allowing arbitrary code execution through improper input handling, and more specifically aligns with CWE-434 which addresses insecure file upload or download scenarios.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with persistent access to affected systems through the compromised web applications. When this vulnerability affects major applications like Horde 1.2.5 and IMP before 2.2.6, the potential for widespread compromise increases significantly, as these are widely deployed web-based email and calendar applications that often run on shared hosting environments or enterprise systems. The vulnerability also demonstrates how insecure configuration settings can compound security issues, as register_globals was a deprecated PHP feature that should never have been enabled in production environments. Attackers can leverage this flaw to establish backdoors, exfiltrate sensitive data, or use the compromised systems as launch points for further attacks within network environments. The vulnerability's impact is particularly severe because it requires minimal privileges to exploit and can be automated through simple HTTP requests, making it a prime target for exploit kits and automated scanning tools.
Mitigation strategies for CVE-2001-1370 involve multiple layers of defensive measures that address both the immediate vulnerability and underlying architectural issues. The most critical remediation is disabling register_globals in PHP configuration, which eliminates the core attack vector by preventing automatic creation of global variables from HTTP parameters. System administrators should also implement proper input validation and sanitization for all user-supplied data, ensuring that any configuration parameters passed to PHPLib are properly verified before use. Additionally, application developers should avoid relying on external library paths that can be manipulated through HTTP requests and instead implement hardcoded or configuration-based path resolution. The use of modern PHP security practices including proper variable scoping, input validation, and secure coding standards should be enforced throughout all web applications. Organizations should also consider implementing web application firewalls to detect and block suspicious parameter manipulation attempts, and establish regular security audits to identify similar vulnerabilities in legacy systems. This vulnerability underscores the importance of following ATT&CK framework principles for application security, particularly focusing on privilege escalation and execution techniques that leverage insecure configurations, and serves as a historical example of why modern security practices such as principle of least privilege and defense in depth are essential for protecting web applications against remote code execution threats.