CVE-2019-7731 in MyWebSQL
Summary
by MITRE
MyWebSQL 3.7 has a remote code execution (RCE) vulnerability after an attacker writes shell code into the database, and executes the Backup Database function with a .php filename for the backup's archive file.
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Analysis
by VulDB Data Team • 07/09/2023
The vulnerability identified as CVE-2019-7731 affects MyWebSQL version 3.7 and represents a critical remote code execution flaw that stems from inadequate input validation and improper file handling within the database backup functionality. This vulnerability operates through a sophisticated attack vector where an authenticated malicious user can inject arbitrary shell code into the database system and subsequently trigger its execution through the Backup Database function. The flaw manifests when the application fails to properly sanitize user-supplied filenames, specifically allowing attackers to specify a .php filename for backup archive files, which then gets executed as PHP code on the server.
The technical implementation of this vulnerability resides in the application's insufficient validation of backup file extensions and the lack of proper file type checking mechanisms. When users initiate a database backup operation, MyWebSQL accepts user-provided filenames without adequate sanitization or validation of the file extension. This creates a path traversal and code execution scenario where attackers can upload malicious PHP code disguised as backup files. The vulnerability aligns with CWE-73 and CWE-94, representing improper neutralization of special elements used in file paths and improper validation of filename parameters respectively. The backup functionality becomes a weaponized pathway for attackers to execute arbitrary commands on the underlying server, potentially leading to complete system compromise.
The operational impact of this vulnerability extends far beyond simple data theft, as it provides attackers with persistent access to the server infrastructure. Once exploited, adversaries can leverage the executed PHP code to establish reverse shells, install backdoors, or perform further reconnaissance within the network. The attack requires only basic database write access and the ability to trigger the backup function, making it particularly dangerous as it can be exploited by attackers with relatively low privileges. This vulnerability creates a persistent threat vector that can be used for lateral movement, data exfiltration, and long-term system compromise, fundamentally undermining the security posture of any organization relying on vulnerable MyWebSQL installations.
Mitigation strategies for CVE-2019-7731 must address both immediate remediation and long-term security hardening measures. Organizations should immediately upgrade to MyWebSQL versions that have patched this vulnerability, as the manufacturer has released updates that properly validate and sanitize backup file extensions. The recommended approach includes implementing strict file extension validation that prevents .php and other potentially dangerous extensions from being used in backup operations. Additionally, organizations should consider implementing network segmentation to limit access to database management interfaces, enforcing principle of least privilege for database users, and implementing robust monitoring of backup operations to detect suspicious file creation patterns. This vulnerability demonstrates the critical importance of input validation and proper file handling in web applications, aligning with ATT&CK technique T1059.007 for command and script injection, and emphasizes the necessity of defense-in-depth strategies to prevent similar vulnerabilities in database management systems.