CVE-2018-11413 in BearAdmin
Summary
by MITRE
An issue was discovered in BearAdmin 0.5. Remote attackers can download arbitrary files via /admin/databack/download.html?name= directory traversal sequences, as demonstrated by name=../application/database.php to read the MySQL credentials in the configuration.
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Analysis
by VulDB Data Team • 02/08/2020
The vulnerability identified as CVE-2018-11413 represents a critical directory traversal flaw in BearAdmin version 0.5 that exposes sensitive system information to remote attackers. This vulnerability exists within the administrative file download functionality of the web application, specifically in the /admin/databack/download.html endpoint where the application fails to properly validate user input. The flaw allows malicious actors to manipulate the 'name' parameter through directory traversal sequences such as '../' to access files outside the intended directory structure. This type of vulnerability falls under the CWE-22 category, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector is particularly dangerous because it enables unauthorized access to critical system files without requiring authentication or privileged access rights.
The technical implementation of this vulnerability exploits the lack of proper input sanitization and validation within the file download mechanism. When an attacker submits a malicious value like '../application/database.php' to the name parameter, the application processes this input without adequate filtering or path resolution checks. This allows the application to interpret the traversal sequences and access files that should remain protected within the application's restricted directory structure. The specific target of exploitation in this case is the MySQL configuration file, which contains database credentials and connection parameters that are essential for database access and system integrity. The vulnerability demonstrates how insufficient input validation can lead to information disclosure, which is a fundamental security principle that violates the principle of least privilege and data confidentiality.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with credentials that can be used for further exploitation within the system. Once an attacker obtains the MySQL credentials, they can potentially access the database directly, modify or delete sensitive data, and establish persistent access to the system infrastructure. This vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to credential access and privilege escalation. The ability to download arbitrary files through a web interface represents a significant compromise of the application's security model and can lead to complete system compromise if the database contains sensitive user information or system configuration details. Organizations running affected versions of BearAdmin face immediate risk of data breaches and unauthorized system access.
Mitigation strategies for CVE-2018-11413 must address both the immediate vulnerability and implement broader security controls to prevent similar issues. The most direct fix involves implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in file operations. This includes rejecting or filtering out directory traversal sequences such as '../' and '..\\' from input parameters before processing. Organizations should also implement proper access controls and authentication mechanisms to ensure that only authorized administrators can access the database backup functionality. The solution should include path normalization and validation techniques that ensure file access occurs only within designated directories, preventing access to parent directories or system files. Additionally, implementing web application firewalls and input validation rules can provide additional layers of protection against similar attacks. Regular security audits and vulnerability assessments should be conducted to identify and remediate similar issues in other applications and systems within the organization's infrastructure.