CVE-2016-6629 in phpMyAdmin
Summary
by MITRE
An issue was discovered in phpMyAdmin involving the $cfg['ArbitraryServerRegexp'] configuration directive. An attacker could reuse certain cookie values in a way of bypassing the servers defined by ArbitraryServerRegexp. All 4.6.x versions (prior to 4.6.4), 4.4.x versions (prior to 4.4.15.8), and 4.0.x versions (prior to 4.0.10.17) are affected.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/24/2024
The vulnerability identified as CVE-2016-6629 represents a critical authentication bypass flaw within phpMyAdmin, a widely used web-based database administration tool. This issue specifically targets the $cfg['ArbitraryServerRegexp'] configuration directive which is designed to control access to database servers by defining regular expressions that match allowed server connections. The flaw allows unauthorized attackers to manipulate cookie values to gain access to database servers that should be restricted by the configured regular expression rules.
The technical implementation of this vulnerability stems from improper validation of cookie data within the phpMyAdmin authentication mechanism. When users authenticate to phpMyAdmin, the system stores server connection information in cookies to maintain session state. However, the vulnerability occurs because the application fails to properly validate or sanitize cookie values before using them to determine server access permissions. Attackers can exploit this by crafting malicious cookie values that contain server connection parameters, effectively bypassing the regular expression validation that should restrict access to specific database servers.
This vulnerability impacts a broad range of phpMyAdmin versions including all 4.6.x releases prior to 4.6.4, 4.4.x versions before 4.4.15.8, and 4.0.x versions before 4.0.10.17. The operational impact is significant as it allows attackers to potentially access multiple database servers within an organization's infrastructure, especially when phpMyAdmin is deployed in environments where multiple database servers are managed through a single interface. The vulnerability essentially undermines the intended security boundary that should prevent unauthorized access to database resources, making it particularly dangerous in multi-tenant or enterprise environments where database isolation is critical.
The exploitation of this vulnerability aligns with attack patterns documented in the ATT&CK framework under the privilege escalation and credential access domains, specifically targeting the use of valid credentials or session tokens to bypass access controls. This issue is categorized as a configuration-based vulnerability that falls under CWE-284 (Improper Access Control) and CWE-290 (Authentication Bypass by Spoofing). Organizations using phpMyAdmin are particularly vulnerable when the tool is deployed without proper network segmentation or when administrators rely solely on the built-in access control mechanisms without implementing additional security layers.
The recommended mitigation strategy involves upgrading to the patched versions of phpMyAdmin where the vulnerability has been addressed through proper cookie validation and sanitization of server connection parameters. Additionally, organizations should implement network-level controls to restrict access to phpMyAdmin interfaces, deploy web application firewalls to monitor and filter suspicious cookie values, and consider implementing additional authentication mechanisms such as two-factor authentication. Security administrators should also review and audit existing phpMyAdmin configurations to ensure that arbitrary server access is properly restricted and that cookie-based session management is properly secured against manipulation attempts.