CVE-2024-1253 Overview
CVE-2024-1253 is an unrestricted file upload vulnerability in the Byzoro Smart S40 Management Platform through build 20240126. The flaw resides in the /useratte/web.php file within the Import Handler component. Attackers can manipulate the file_upload argument to upload arbitrary files without restriction, classified under [CWE-434]. The exploit has been publicly disclosed and is trackable as VulDB entry VDB-252992. The vendor was contacted about this disclosure but did not respond, leaving affected deployments without an official patch.
Critical Impact
Authenticated remote attackers can upload arbitrary files to the Smart S40 platform, enabling code execution, persistence, and full compromise of the management interface.
Affected Products
- Byzoro Smart S40 Firmware (versions up to 20240126)
- Byzoro Smart S40 hardware appliance
- Byzoro Smart S40 Management Platform Import Handler component
Discovery Timeline
- 2024-02-06 - CVE-2024-1253 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-1253
Vulnerability Analysis
The vulnerability exists in the Import Handler component of the Byzoro Smart S40 Management Platform. The /useratte/web.php endpoint accepts a file_upload parameter without enforcing restrictions on file type, extension, or content. Attackers with valid credentials can submit crafted HTTP requests carrying executable payloads such as PHP webshells.
Once uploaded, the attacker-controlled file resides within the web-accessible directory tree. Requesting the uploaded file triggers server-side execution under the privileges of the web application. This grants attackers a foothold on the management platform, which controls network infrastructure and policy enforcement.
The attack requires network access to the management interface and high-privilege authentication, per the CVSS vector. Successful exploitation results in complete loss of confidentiality, integrity, and availability. The publicly available exploit documentation on GitHub increases the likelihood of opportunistic targeting.
Root Cause
The root cause is missing validation of user-supplied file uploads in /useratte/web.php. The Import Handler does not enforce an allowlist of permitted MIME types, extensions, or file signatures. It also fails to relocate uploaded content outside the webroot or randomize filenames to prevent direct execution.
Attack Vector
Exploitation proceeds over the network against the platform's HTTP management interface. An authenticated attacker sends a POST request to /useratte/web.php with a malicious file supplied via the file_upload parameter. The server stores the file in a web-accessible location, allowing the attacker to invoke it directly through a subsequent HTTP request and execute arbitrary code. Technical exploitation details are documented in the GitHub Exploit Documentation.
Detection Methods for CVE-2024-1253
Indicators of Compromise
- Unexpected .php, .jsp, or script files present under directories serving /useratte/ content.
- POST requests to /useratte/web.php containing a file_upload parameter with executable MIME types.
- Outbound connections initiated by the web server process to unfamiliar external hosts following upload activity.
- New administrative user accounts or configuration changes on the Smart S40 platform without a corresponding change ticket.
Detection Strategies
- Inspect web server access logs for anomalous POST volumes to /useratte/web.php and correlate with subsequent GET requests to newly created filenames.
- Deploy file integrity monitoring on the Smart S40 web application directories to alert on new or modified script files.
- Apply web application firewall rules that block uploads containing PHP tags or executable signatures to the Import Handler endpoint.
Monitoring Recommendations
- Forward Smart S40 HTTP and application logs to a centralized analytics platform for retention and correlation.
- Baseline normal administrative upload activity and alert on deviations in file count, size, or extension.
- Monitor process trees originating from the web server for spawned shells, interpreters, or reconnaissance utilities.
How to Mitigate CVE-2024-1253
Immediate Actions Required
- Restrict network access to the Smart S40 management interface to trusted administrative subnets only.
- Rotate credentials for all accounts capable of accessing /useratte/web.php and enforce strong authentication.
- Audit the web application directory tree for unauthorized files created since deployment and remove any suspicious artifacts.
- Isolate exposed Smart S40 appliances from production traffic until compensating controls are in place.
Patch Information
No vendor patch is available. According to the disclosure, Byzoro was contacted early but did not respond. Organizations operating the Smart S40 platform must rely on compensating controls until the vendor releases a fix. Track updates through the VulDB entry #252992.
Workarounds
- Place the management interface behind a VPN or bastion host requiring multi-factor authentication.
- Configure a reverse proxy or web application firewall to block requests to /useratte/web.php that carry executable file signatures.
- Remove execute permissions on upload destination directories at the filesystem level where feasible.
- Disable or restrict the Import Handler functionality if it is not required for daily operations.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
