CVE-2018-18487 in Gxlcms
Summary
by MITRE
In \lib\admin\action\dataaction.class.php in Gxlcms v2.0, the database backup filename generation uses mt_rand() unsafely, resulting in predictable database backup file locations.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/05/2020
The vulnerability identified as CVE-2018-18487 resides within the Gxlcms v2.0 content management system where the database backup functionality suffers from predictable filename generation due to improper use of the mt_rand() function. This flaw exists in the file lib/admin/action/dataaction.class.php which handles administrative database backup operations. The insecure implementation of random number generation creates a significant security risk by allowing unauthorized users to predict backup file locations and potentially access sensitive database information. The vulnerability stems from the predictable nature of mt_rand() when used without proper seeding or cryptographic randomness, making it susceptible to exploitation by attackers who can enumerate or guess backup filenames.
The technical implementation flaw involves the use of mt_rand() for generating backup filenames without adequate entropy sources or proper randomization techniques. This function, while suitable for general purposes, lacks the cryptographic security properties required for generating unpredictable identifiers in security-sensitive contexts. When the system generates database backup files, it creates filenames based on these predictable random numbers, enabling attackers to construct valid backup file paths and potentially gain access to database dumps containing sensitive user information, configuration data, and other confidential system details. This weakness directly relates to CWE-330 Use of Insufficiently Random Values, which specifically addresses the use of weak random number generators in security contexts.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential system compromise and data breaches. An attacker who can predict backup file locations can attempt to access database backups directly, potentially obtaining sensitive information such as user credentials, personal data, application configurations, and other confidential system elements. The vulnerability enables a form of privilege escalation through unauthorized data access, as backup files often contain comprehensive database snapshots that include all system data. This risk is particularly severe in environments where database backups contain user authentication details, financial information, or other sensitive personal data. The attack surface is further expanded because the vulnerability affects the administrative functionality, potentially allowing attackers to escalate privileges or access restricted system information.
Mitigation strategies for this vulnerability should focus on implementing cryptographically secure random number generation for backup filename creation. Organizations should replace the mt_rand() function with cryptographically secure alternatives such as random_bytes() or openssl_random_pseudo_bytes() functions available in modern php versions. The system should also implement proper file access controls and ensure that backup files are stored in secure directories with restricted permissions. Additional defensive measures include implementing rate limiting for backup operations, logging access attempts to backup files, and conducting regular security audits of file generation processes. The solution aligns with ATT&CK technique T1213.002 Data from Information Repositories, where adversaries may access database backup files. Organizations should also consider implementing automated monitoring for predictable filename patterns and ensure that all random number generation in security-sensitive contexts meets cryptographic strength requirements. The fix should be applied across all administrative functions that generate identifiers or filenames to prevent similar vulnerabilities in other components of the system.