CVE-2020-20495 in Bludit
Summary
by MITRE • 09/01/2021
bludit v3.13.0 contains an arbitrary file deletion vulnerability in the backup plugin via the `deleteBackup' parameter.
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Analysis
by VulDB Data Team • 09/04/2021
The vulnerability identified as CVE-2020-20495 affects bludit version 3.13.0 and represents a critical arbitrary file deletion flaw within the backup plugin functionality. This vulnerability arises from insufficient input validation and access control measures in the plugin's deleteBackup parameter handling mechanism. The issue allows authenticated attackers with sufficient privileges to delete arbitrary files on the server filesystem through crafted requests that manipulate the backup deletion process. The vulnerability specifically targets the backup plugin component of bludit, which is designed to manage website backup operations but fails to properly sanitize user-supplied input before executing file system operations. This flaw directly violates security principles of input validation and privilege separation, creating a path for malicious actors to potentially compromise the entire web application environment.
The technical implementation of this vulnerability stems from the backup plugin's failure to properly validate or sanitize the deleteBackup parameter, which is typically used to specify which backup files should be removed from the system. When an authenticated user submits a request containing a maliciously crafted deleteBackup value, the application processes this input without adequate verification, leading to unauthorized file deletion operations. The vulnerability manifests as a path traversal or directory traversal issue where attacker-controlled input can manipulate the file system operations to target files beyond the intended backup directories. This represents a classic example of improper input validation that aligns with CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') and CWE-77 - Improper Neutralization of Special Elements used in a Command ('Command Injection') categories. The flaw essentially allows an attacker to bypass normal file system access controls and delete any file that the web application process has permissions to access.
The operational impact of CVE-2020-20495 extends beyond simple file deletion capabilities and can result in severe consequences for affected systems. An attacker exploiting this vulnerability could potentially delete critical application files, configuration data, database files, or even system binaries that compromise the entire web application infrastructure. The vulnerability creates a persistent threat vector that could be leveraged for further attacks including complete system compromise, data destruction, or service disruption. Depending on the system configuration and file permissions, this vulnerability could enable attackers to delete backup files that would prevent system recovery, or target configuration files that would render the application unusable. The impact is particularly severe in environments where the web application runs with elevated privileges or where backup files contain sensitive data that could be deleted to prevent forensic analysis. This vulnerability also aligns with ATT&CK technique T1485 - Data Destruction and T1059 - Command and Scripting Interpreter, as it enables attackers to execute destructive operations through command injection mechanisms.
Mitigation strategies for CVE-2020-20495 should prioritize immediate patching of the affected bludit version to the latest secure release that addresses the backup plugin vulnerability. Organizations should implement strict input validation and sanitization measures for all user-supplied parameters, particularly those related to file system operations. Access controls must be enforced through proper authentication and authorization checks to ensure that only legitimate administrators can perform backup operations. Network segmentation and monitoring should be implemented to detect unusual file deletion patterns or unauthorized backup management activities. Additionally, regular security audits of web applications should include verification of plugin security configurations and input validation mechanisms. The vulnerability serves as a reminder of the importance of maintaining up-to-date software components and implementing robust security controls around file system operations. System administrators should also consider implementing automated backup strategies that protect against data loss from such vulnerabilities and establish monitoring procedures to detect unauthorized file deletion activities. Organizations should review their incident response procedures to ensure readiness for potential exploitation of similar file system vulnerabilities that could compromise application integrity and availability.