CVE-2020-36005 in AppCMS
Summary
by MITRE • 06/04/2021
AppCMS 2.0.101 in /admin/app.php has an arbitrary file deletion vulnerability which allows attackers to delete arbitrary files on the site.
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Analysis
by VulDB Data Team • 06/07/2021
The vulnerability identified as CVE-2020-36005 affects AppCMS version 2.0.101 and resides within the administrative component at /admin/app.php. This represents a critical security flaw that exposes the application to unauthorized file manipulation capabilities. The vulnerability stems from insufficient input validation and access control mechanisms within the file management functionality, allowing malicious actors to exploit the system's file deletion mechanisms without proper authorization. The flaw specifically impacts the administrative interface where file operations are processed, creating a pathway for attackers to target any file within the application's directory structure.
This arbitrary file deletion vulnerability operates through a lack of proper parameter sanitization and validation within the file handling routines. Attackers can craft malicious requests that bypass normal access controls and execute file deletion operations against arbitrary paths on the server. The technical implementation appears to rely on user-supplied parameters that are directly used in file system operations without adequate filtering or authorization checks. This type of vulnerability falls under CWE-22 which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The flaw essentially allows attackers to manipulate the file system by providing crafted input that can target files beyond the intended scope of the application's normal operations.
The operational impact of this vulnerability is severe and multifaceted. An attacker who successfully exploits this flaw can delete critical application files, configuration data, user databases, or even system binaries that could lead to complete system compromise. The vulnerability enables attackers to potentially remove core application components, rendering the system inoperable or creating backdoor opportunities for further exploitation. This arbitrary deletion capability also allows for data destruction attacks that can cause significant business disruption and potential compliance violations. The attack surface extends beyond simple file removal to include potential privilege escalation scenarios where attackers might delete security-related files or logs that would otherwise prevent further unauthorized access.
From a threat modeling perspective, this vulnerability aligns with several ATT&CK techniques including T1486 for data destruction and T1566 for credential access through manipulation of application components. The attack chain typically begins with reconnaissance to identify the vulnerable application version, followed by exploitation of the file deletion functionality to target critical system files. Organizations should consider implementing network segmentation and monitoring for unusual file deletion patterns as part of their defensive strategy. The vulnerability demonstrates the critical importance of input validation and access control enforcement in administrative interfaces. Proper mitigation requires immediate patching of the affected application version, implementation of strict file access controls, and comprehensive audit logging of all file operations. Additionally, organizations should conduct thorough security assessments to identify similar vulnerabilities in other administrative components and ensure that all file system operations are properly validated and authorized before execution.
The security implications extend beyond immediate exploitation to include long-term system integrity concerns. When attackers can delete arbitrary files, they may target backup files, log files, or security configuration data that would normally prevent further compromise. This vulnerability essentially creates a persistent threat vector that can be leveraged for both immediate damage and future attacks. Organizations should also consider implementing file integrity monitoring solutions and ensuring that administrative interfaces have robust authentication mechanisms and input validation controls. The vulnerability highlights the need for defense in depth strategies where multiple layers of protection are implemented to prevent unauthorized access to critical system resources. Proper implementation of least privilege principles and regular security testing can help prevent exploitation of similar vulnerabilities in other applications.