CVE-2016-6631 in phpMyAdmin
Summary
by MITRE
An issue was discovered in phpMyAdmin. A user can execute a remote code execution attack against a server when phpMyAdmin is being run as a CGI application. Under certain server configurations, a user can pass a query string which is executed as a command-line argument by the file generator_plugin.sh. 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.
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Analysis
by VulDB Data Team • 10/05/2022
The vulnerability identified as CVE-2016-6631 represents a critical remote code execution flaw in phpMyAdmin that emerges specifically when the application operates in CGI mode. This configuration presents a unique attack surface where user-controllable input can be improperly processed and executed as system commands. The vulnerability stems from insufficient input validation within the file generation functionality, creating a pathway for malicious actors to inject arbitrary commands through carefully crafted query parameters. The flaw affects multiple version streams of phpMyAdmin including the 4.6.x series prior to 4.6.4, 4.4.x series prior to 4.4.15.8, and 4.0.x series prior to 4.0.10.17, indicating a widespread impact across the software's release history. This issue particularly affects environments where phpMyAdmin is deployed as a CGI application rather than in more secure FastCGI or mod_php configurations, making it a significant concern for administrators running these specific deployment scenarios.
The technical exploitation of this vulnerability occurs through the file generator_plugin.sh script which is invoked by phpMyAdmin during certain file generation operations. When phpMyAdmin operates in CGI mode, user-supplied parameters can be directly incorporated into command-line arguments without proper sanitization, allowing attackers to inject malicious commands that get executed with the privileges of the web server process. This represents a classic command injection vulnerability where the application fails to properly escape or validate user input before using it in system calls. The attack vector specifically targets the query string parameters that are processed by the file generation plugin, enabling an attacker to execute arbitrary shell commands on the server. This type of vulnerability maps directly to CWE-77 and CWE-94 in the Common Weakness Enumeration catalog, which categorize it as a command injection flaw that can lead to arbitrary code execution.
The operational impact of CVE-2016-6631 extends far beyond simple data compromise, as successful exploitation provides attackers with complete control over the affected server. Once executed, the remote code execution allows malicious actors to perform system-level operations including but not limited to file manipulation, process management, network reconnaissance, privilege escalation, and persistence establishment. The vulnerability essentially provides an attacker with a backdoor into the server environment, potentially enabling them to access sensitive databases, extract confidential information, or use the compromised server as a launch point for further attacks within the network infrastructure. Given that phpMyAdmin is commonly used for database administration tasks, the compromise of such a system can lead to widespread data breaches and system infiltration. This vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1078.004 for valid accounts, as it allows for the execution of system commands and can be used to establish persistent access to compromised systems.
Organizations affected by this vulnerability should immediately implement mitigation strategies focusing on both immediate remediation and long-term security improvements. The primary recommendation involves upgrading to patched versions of phpMyAdmin, specifically versions 4.6.4, 4.4.15.8, and 4.0.10.17 respectively, which contain the necessary fixes to prevent command injection in the file generation plugin. Additionally, administrators should consider modifying their server configurations to avoid running phpMyAdmin in CGI mode where possible, as this deployment method inherently increases the attack surface. Network segmentation and access controls should be implemented to limit exposure, while monitoring systems should be configured to detect unusual command execution patterns. Security measures such as input validation, parameterized queries, and proper privilege separation should be enforced to prevent similar vulnerabilities from emerging in other components of the application stack. The vulnerability demonstrates the critical importance of input sanitization and proper command execution handling in web applications, particularly those that interface with system-level operations.