CVE-2013-2162 in MySQL
Summary
by MITRE
Race condition in the post-installation script (mysql-server-5.5.postinst) for MySQL Server 5.5 for Debian GNU/Linux and Ubuntu Linux creates a configuration file with world-readable permissions before restricting the permissions, which allows local users to read the file and obtain sensitive information such as credentials.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability described in CVE-2013-2162 represents a critical race condition flaw within the MySQL Server 5.5 post-installation script on Debian and Ubuntu systems. This issue stems from improper file permission handling during the package installation process, creating a window of opportunity for local attackers to exploit the system. The race condition occurs specifically in the mysql-server-5.5.postinst script where configuration files are initially created with permissive world-readable permissions before the script executes the necessary permission restriction commands. This temporal gap between file creation and permission enforcement allows malicious local users to access sensitive information that should remain protected during the installation process.
The technical implementation of this vulnerability involves a classic race condition pattern where the order of operations creates a security boundary that can be exploited. During the installation of MySQL Server 5.5, the post-installation script generates configuration files containing database credentials, encryption keys, and other sensitive authentication material. The flaw manifests when the script first creates these files with default permissions that include world-read access, and only subsequently attempts to restrict these permissions through chmod operations. This sequence creates a brief window where any local user can read the configuration file contents, potentially extracting database passwords, administrative credentials, and other confidential information that could be used for further attacks or system compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with valuable credentials that can be leveraged for privilege escalation and persistent access to database systems. Local users who exploit this vulnerability gain access to MySQL administrative accounts, which could lead to full database compromise, data exfiltration, and potential lateral movement within the network. The vulnerability affects multiple Debian-based distributions and Ubuntu systems, making it particularly widespread and dangerous in environments where multiple systems are running the affected MySQL versions. The attack vector requires only local system access, making it difficult to detect and mitigate, as it does not involve network-based exploitation or external attack surfaces.
This vulnerability aligns with CWE-367, which specifically addresses Time-of-Check to Time-of-Use (TOCTOU) race conditions, and relates to ATT&CK technique T1003.001 for OS credential dumping and T1078.004 for valid accounts. The race condition creates a scenario where the system's security checks occur at one point in time but the actual resource state changes before the security measures are fully enforced. Organizations running affected MySQL installations should immediately apply security patches from their respective distribution vendors, as the vulnerability has been addressed through proper file permission handling in updated post-installation scripts. Additionally, system administrators should review existing configuration files for potential exposure and implement monitoring for unauthorized access attempts to sensitive system files, while ensuring that all systems undergo regular security audits to identify similar vulnerabilities in other software packages.