CVE-2021-36623 in Phone Shop Sales Management System
Summary
by MITRE • 08/03/2021
Arbitrary File Upload in Sourcecodester Phone Shop Sales Management System 1.0 enables RCE.
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Analysis
by VulDB Data Team • 08/07/2021
The CVE-2021-36623 vulnerability represents a critical arbitrary file upload flaw in the Sourcecodester Phone Shop Sales Management System version 1.0 that directly enables remote code execution capabilities. This vulnerability stems from insufficient input validation and sanitization within the application's file upload functionality, allowing malicious actors to bypass security controls and upload potentially dangerous files to the target system. The flaw exists in the system's handling of user-supplied file data, where proper file type restrictions and content verification mechanisms are either absent or inadequately implemented. Security researchers identified that the application fails to properly validate file extensions, MIME types, or file contents during the upload process, creating an exploitable entry point for attackers seeking to compromise the system.
The technical implementation of this vulnerability allows attackers to upload malicious files such as web shells, php scripts, or other executable content that can be executed within the application's context. This arbitrary file upload capability directly maps to CWE-434 which describes insecure file upload vulnerabilities where applications accept files from untrusted sources without proper validation. The vulnerability's impact is amplified by the fact that the uploaded files can be executed directly by the web server, providing attackers with a persistent backdoor into the system. Attackers can leverage this vulnerability to execute arbitrary commands on the target server, potentially gaining full administrative control over the application and underlying infrastructure.
Operationally, this vulnerability presents a severe risk to organizations using the affected Phone Shop Sales Management System, as it enables attackers to establish persistent access, exfiltrate sensitive data, and potentially escalate privileges within the network. The remote code execution capability means that attackers do not need physical access or prior credentials to exploit the system, making it particularly dangerous in environments where such applications are exposed to external networks. The vulnerability also aligns with several ATT&CK techniques including T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, as attackers can execute malicious code through the compromised upload functionality. Organizations running this system are at risk of data breaches, system compromise, and potential lateral movement within their network infrastructure.
Mitigation strategies for CVE-2021-36623 should focus on immediate patching of the affected system, implementing robust file upload validation controls, and establishing proper access controls for file upload functionality. Organizations must ensure that all file uploads are validated against a strict whitelist of allowed file types, with proper MIME type checking and content analysis. The system should enforce strict file name sanitization and store uploaded files outside the web root directory to prevent direct execution. Additional security measures include implementing web application firewalls, restricting file upload capabilities to authenticated users only, and conducting regular security audits of file handling mechanisms. Organizations should also monitor for suspicious upload activities and implement proper logging and alerting for file upload operations. The vulnerability demonstrates the critical importance of proper input validation and the principle of least privilege in web application security, as highlighted in industry standards such as OWASP Top Ten and NIST cybersecurity frameworks.