CVE-2026-1021 Overview
CVE-2026-1021 is a critical Arbitrary File Upload vulnerability affecting the Police Statistics Database System developed by Gotac. This vulnerability allows unauthenticated remote attackers to upload and execute web shell backdoors on vulnerable systems, enabling arbitrary code execution on the server. The flaw stems from improper validation of uploaded files (CWE-434: Unrestricted Upload of File with Dangerous Type), allowing malicious actors to bypass security controls and deploy persistent backdoors.
Critical Impact
Unauthenticated attackers can achieve complete server compromise through web shell deployment, potentially exposing sensitive law enforcement data and enabling lateral movement within affected networks.
Affected Products
- Gotac Police Statistics Database System
Discovery Timeline
- 2026-01-16 - CVE-2026-1021 published to NVD
- 2026-01-16 - Last updated in NVD database
Technical Details for CVE-2026-1021
Vulnerability Analysis
This vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type), representing a severe file upload security flaw. The Police Statistics Database System fails to properly validate file types during the upload process, allowing attackers to upload executable scripts such as web shells. Since the vulnerability requires no authentication, any network-accessible attacker can exploit this flaw remotely.
The attack can be executed over the network without any user interaction, and no prior privileges or authentication are required. A successful exploit grants the attacker high-level access to confidentiality, integrity, and availability of the target system, enabling complete server compromise.
Root Cause
The root cause of this vulnerability is the absence of proper file type validation and sanitization during the upload process. The application fails to implement server-side checks that verify uploaded file extensions, MIME types, and file contents. This oversight allows attackers to upload files with dangerous extensions (such as .php, .asp, .jsp) that can be executed by the web server.
Attack Vector
The attack leverages the network-accessible file upload functionality in the Police Statistics Database System. An attacker can craft a malicious request containing a web shell payload disguised or directly uploaded as an executable server-side script. Once uploaded, the attacker accesses the web shell through a direct URL request, gaining the ability to execute arbitrary commands on the underlying server with the privileges of the web server process.
The exploitation flow typically involves:
- Identifying the vulnerable upload endpoint in the Police Statistics Database System
- Crafting a web shell payload (PHP, ASP, JSP depending on server technology)
- Uploading the malicious file through the unrestricted upload mechanism
- Accessing the uploaded web shell via its predictable or disclosed path
- Executing arbitrary commands on the compromised server
For technical details regarding this vulnerability, refer to the TW-CERT Security Advisory.
Detection Methods for CVE-2026-1021
Indicators of Compromise
- Unexpected files with executable extensions (.php, .asp, .aspx, .jsp) appearing in upload directories
- Web server logs showing POST requests to upload endpoints followed by GET requests to unusual file paths
- Outbound connections from web server processes to external command and control infrastructure
- Unusual process spawning from web server processes (e.g., cmd.exe, /bin/sh, powershell.exe)
Detection Strategies
- Monitor file system changes in web-accessible directories for newly created executable scripts
- Implement web application firewall (WAF) rules to detect common web shell signatures in upload requests
- Analyze web server access logs for sequential patterns of file uploads followed by direct file access
- Deploy endpoint detection and response (EDR) solutions to identify command execution from web server processes
Monitoring Recommendations
- Enable detailed logging for all file upload operations including source IP, uploaded filename, and destination path
- Implement real-time alerting for new executable files created in web directories
- Monitor network traffic for command and control patterns originating from web server processes
- Conduct regular file integrity monitoring on web application directories
How to Mitigate CVE-2026-1021
Immediate Actions Required
- Restrict network access to the Police Statistics Database System to trusted IP ranges only
- Implement a web application firewall with rules blocking common web shell patterns
- Audit upload directories for any suspicious or unexpected files and remove confirmed web shells
- Enable enhanced logging and monitoring on affected systems while awaiting vendor patches
Patch Information
Organizations should contact Gotac directly for official patches and security updates. For additional information, refer to the TW-CERT Security Advisory and the TW-CERT Incident Report.
Workarounds
- Implement strict whitelist-based file extension validation at the web server level
- Configure the web server to prevent script execution in upload directories using .htaccess or equivalent configurations
- Deploy network segmentation to isolate the Police Statistics Database System from critical infrastructure
- Consider temporarily disabling file upload functionality until a patch is available
# Example Apache configuration to disable script execution in upload directory
<Directory "/var/www/app/uploads">
php_admin_flag engine off
Options -ExecCGI
RemoveHandler .php .phtml .php3 .php4 .php5 .phps
AddType text/plain .php .phtml .php3 .php4 .php5 .phps
</Directory>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
