CVE-2021-43008 in Adminer
Summary
by MITRE • 04/05/2022
Improper Access Control in Adminer versions 1.12.0 to 4.6.2 (fixed in version 4.6.3) allows an attacker to achieve Arbitrary File Read on the remote server by requesting the Adminer to connect to a remote MySQL database.
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Analysis
by VulDB Data Team • 04/06/2022
The vulnerability CVE-2021-43008 represents a critical improper access control flaw in Adminer database management tool affecting versions 1.12.0 through 4.6.2. This vulnerability resides in the application's handling of remote database connections and demonstrates a significant security weakness that can be exploited to achieve arbitrary file read capabilities on the target server. The flaw specifically manifests when Adminer attempts to establish connections to remote MySQL databases, creating an attack vector that bypasses normal access control mechanisms. This issue falls under the CWE-284 access control weakness category, which specifically addresses improper access control in software applications. The vulnerability enables attackers to read arbitrary files on the server where Adminer is installed, potentially exposing sensitive data including configuration files, database credentials, and application source code. The attack scenario involves an attacker crafting malicious database connection parameters that leverage Adminer's functionality to access files on the target system through the database connection interface.
The technical implementation of this vulnerability stems from insufficient input validation and improper sanitization of database connection parameters within Adminer's remote connection handling code. When users attempt to connect to remote MySQL databases through Adminer's interface, the application processes connection strings and parameters without adequate validation of file paths or access restrictions. This allows attackers to manipulate the connection process to reference local files on the server instead of remote database endpoints. The flaw exploits the way Adminer handles database connection errors and file access operations during remote connection attempts, where the application's error handling routines inadvertently provide access to file system resources. The vulnerability is particularly dangerous because it leverages legitimate application functionality to achieve unauthorized file access, making detection more challenging. According to ATT&CK framework technique T1566.001, this vulnerability represents a credential access and privilege escalation vector through exploitation of application-level weaknesses.
The operational impact of CVE-2021-43008 extends beyond simple data theft to encompass complete system compromise and information disclosure. Attackers can leverage this vulnerability to read sensitive configuration files containing database credentials, application secrets, and system configuration parameters that could enable further attacks. The ability to read arbitrary files opens the door for attackers to discover additional vulnerabilities within the application or server environment, potentially leading to full system compromise. Organizations running vulnerable versions of Adminer face significant risk exposure, particularly those using the tool for database administration in production environments. The vulnerability affects both the database connection functionality and the underlying file system access controls, making it a critical concern for security teams responsible for database management tools. Network security monitoring systems may not immediately detect this attack vector since it appears to be legitimate database connection activity, creating a stealthy threat that can persist undetected for extended periods. The vulnerability also impacts compliance requirements since it can lead to unauthorized access to sensitive data that organizations must protect under various regulatory frameworks.
Organizations should immediately upgrade to Adminer version 4.6.3 or later to remediate this vulnerability, as this represents the official fix provided by the software vendor. The mitigation strategy should include comprehensive vulnerability scanning to identify all instances of vulnerable Adminer versions within the organization's infrastructure. Security teams should implement network monitoring to detect suspicious database connection patterns that might indicate exploitation attempts, particularly those involving unusual file path references or connection parameters. Additional protective measures include restricting network access to Adminer installations, implementing proper firewall rules to limit database connection capabilities, and conducting regular security assessments of database management tools. The vulnerability highlights the importance of input validation and proper access control implementation in web applications, particularly those handling database connections and file system operations. Organizations should also review their database management practices and ensure that administrative tools are properly secured and isolated from untrusted network segments to minimize the attack surface for similar vulnerabilities.