Unrestricted File Upload in Online Job Portal 1.0

Executive Summary

CVE-2026-15677 is an unrestricted file upload vulnerability in the Online Job Portal 1.0 software, specifically in the /JobSeekerInsert.php file. The vulnerability occurs when an attacker manipulates the 'txtFile' argument during the file upload process.

This flaw allows attackers to upload arbitrary files, including malicious scripts like PHP webshells, without proper validation, MIME type checking, or file size restrictions. The upload directory is web-accessible and permits PHP execution, which can lead to Remote Code Execution (RCE) with the privileges of the web server user (e.g., www-data).

The vulnerability is exploitable remotely and does not require authentication, as it can be triggered during the public registration process. The root cause is improper handling of file uploads, where the original filename is used without sanitization, and the upload directory lacks protections against PHP execution.

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Detection Guidance

To detect this vulnerability on your network or system, you can perform the following checks:

• Verify if the Online Job Portal 1.0 is running by checking for the presence of the /JobSeekerInsert.php file. This can be done using a web request or by inspecting the web server directories.
• Check for unusual or unexpected file uploads in the web-accessible directories, particularly those with PHP extensions or other executable file types. Look for files that may have been uploaded without proper validation.
• Use a vulnerability scanner or web application security tool (e.g., OWASP ZAP, Burp Suite, or Nessus) to scan for unrestricted file upload vulnerabilities in the Online Job Portal application.
• Inspect the web server logs for suspicious upload activities, such as repeated attempts to upload files with unusual extensions or large file sizes.
• Manually test the file upload functionality by attempting to upload a benign file (e.g., a text file renamed to .php) and checking if it is accepted and accessible via the web.

Example command to check for the presence of the vulnerable file using curl:

• curl -I http://<target-ip-or-domain>/JobSeekerInsert.php

Example command to search for recently uploaded PHP files in the web directory (Linux):

• find /var/www/html -name "*.php" -mtime -7 -type f

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Impact Analysis

This vulnerability can have severe impacts if exploited, including:

• Full server compromise: Attackers can execute arbitrary code on the server, gaining control over the system.
• Data exfiltration: Sensitive data stored on the server, such as user information or job application details, can be stolen.
• Malware distribution: Attackers can upload malware or phishing pages, which can be used to target users visiting the portal.
• Pivoting to internal networks: If the server is part of a larger network, attackers can use it as a foothold to move laterally and compromise other systems.
• Defacement or reputational damage: The portal can be defaced or used to spread malicious content, harming the organization's reputation.

Since the vulnerability is publicly exploitable and requires no authentication, the risk of attack is high.

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Compliance Impact

This vulnerability can lead to non-compliance with several common standards and regulations, including:

• GDPR (General Data Protection Regulation): If the portal processes or stores personal data of EU citizens, a breach resulting from this vulnerability could lead to unauthorized access or exfiltration of data. This violates GDPR's requirements for data protection and may result in significant fines (up to 4% of global revenue or €20 million, whichever is higher).
• HIPAA (Health Insurance Portability and Accountability Act): If the portal handles protected health information (PHI), exploitation of this vulnerability could lead to unauthorized access or disclosure of PHI. This violates HIPAA's Security Rule and Privacy Rule, potentially resulting in penalties and legal action.
• PCI DSS (Payment Card Industry Data Security Standard): If the portal processes payment card information, a breach could expose cardholder data. This violates PCI DSS requirements for securing cardholder data, leading to fines, increased transaction fees, or loss of payment processing capabilities.
• ISO 27001: This standard requires organizations to implement controls for securing information assets. A vulnerability like this indicates a failure to implement adequate security measures, such as proper file upload validation and access controls, which could result in non-compliance.

Exploitation of this vulnerability could also trigger breach notification requirements under laws like GDPR, HIPAA, or state-level data breach laws, leading to additional legal and reputational consequences.

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Mitigation Strategies

To mitigate this vulnerability, take the following immediate steps:

• Disable or restrict access to the /JobSeekerInsert.php file until a patch or fix is applied. This can be done by renaming the file, removing it, or restricting access via web server configurations (e.g., .htaccess rules).
• Implement strict file upload validation to ensure only allowed file types (e.g., PDF, DOCX) are accepted. Reject files with executable extensions like .php, .jsp, or .asp.
• Sanitize filenames by removing or replacing special characters and ensuring the filename does not contain malicious payloads (e.g., path traversal sequences).
• Store uploaded files in a non-web-accessible directory or configure the web server to prevent execution of uploaded files. For example, disable PHP execution in the upload directory using .htaccess or web server rules.
• Enforce MIME type checking to ensure the uploaded file matches its declared type. Reject files that do not match the expected MIME type.
• Apply file size limits to prevent large file uploads that could exhaust server resources.
• Monitor the upload directory for suspicious files and set up alerts for unusual upload activities.
• Update the Online Job Portal application to the latest version if a patch is available. If no patch exists, consider disabling the file upload functionality until a fix is provided.
• Review and harden the web server configuration to limit the impact of potential exploits. For example, disable directory listing and restrict permissions for the web server user.

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