CVE-2005-1820 in Zeroboard
Summary
by MITRE
zboard.php in Zeroboard version 4.1pl2 to 4.1pl5 allows remote attackers to execute arbitrary PHP code via improper quoting when using the preg_replace function.
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Analysis
by VulDB Data Team • 07/09/2018
The vulnerability identified as CVE-2005-1820 resides within the zboard.php script of Zeroboard versions 4.1pl2 through 4.1pl5, representing a critical security flaw that enables remote code execution through improper handling of user input. This issue stems from the insecure usage of the preg_replace function without proper input sanitization, creating a pathway for malicious actors to inject and execute arbitrary PHP code on the affected server. The vulnerability demonstrates a classic example of code injection where attacker-controlled data flows directly into a function capable of interpreting PHP code, fundamentally compromising the application's security posture.
The technical root cause of this vulnerability lies in the improper quoting mechanisms employed within the preg_replace function call, which allows attackers to manipulate input parameters in ways that bypass normal validation checks. When user-supplied data is processed through preg_replace without adequate sanitization, the function can interpret special characters and delimiters as code execution directives rather than plain text. This creates a scenario where an attacker can craft malicious input that, when processed by the vulnerable function, results in the execution of arbitrary PHP commands on the target server. The flaw specifically relates to the lack of proper input validation and sanitization practices that should have been implemented to prevent such injection attacks.
From an operational impact perspective, this vulnerability presents a severe risk to organizations running affected Zeroboard installations, as it allows full remote code execution capabilities without requiring authentication. Attackers can leverage this vulnerability to gain complete control over the affected web server, potentially leading to data breaches, service disruption, and further lateral movement within network infrastructures. The vulnerability's remote exploitability means that attackers can target the system from anywhere on the internet, making it particularly dangerous for publicly accessible web applications. This type of vulnerability directly violates the principle of least privilege and can result in complete system compromise, as demonstrated by the ATT&CK framework's remote code execution tactics.
The security implications extend beyond immediate code execution to encompass broader system compromise and data integrity violations. Organizations affected by this vulnerability face potential exposure of sensitive user data, unauthorized access to server resources, and possible use as a foothold for further attacks within their network infrastructure. The vulnerability's classification aligns with CWE-94, which addresses "Improper Control of Generation of Code ('Code Injection')" and specifically relates to CWE-77, "Improper Neutralization of Special Elements used in a Command ('Command Injection')", though the specific context involves PHP code injection rather than command injection. Mitigation strategies should focus on immediate patching of the affected Zeroboard versions, implementation of proper input validation mechanisms, and deployment of web application firewalls to detect and block malicious payloads attempting to exploit this vulnerability. Additionally, organizations should conduct comprehensive security assessments of their web applications to identify similar patterns of insecure coding practices that could lead to comparable vulnerabilities.