CVE-2025-41020

Executive Summary

CVE-2025-41020 is an Insecure Direct Object Reference (IDOR) vulnerability identified in Sergestec's Exito v8.0, a web-based application. The flaw resides in the /admin/ticket_a4.php endpoint, where the id parameter is not properly validated. This allows an unauthenticated or low-privileged attacker to enumerate or manipulate the id parameter to access support tickets and associated data belonging to other customers. The vulnerability is classified under MITRE ATT&CK tactic T1190 (Exploit Public-Facing Application) and CWE-639 (Authorization Bypass Through User-Controlled Key). No official patch has been released, and no public exploit code or Nuclei template is available at this time. The risk is elevated due to the lack of authentication checks on the parameter, potentially leading to significant data leakage.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a custom PHP application (Exito v8.0) developed by Sergestec. No open-source package dependencies are affected.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0 in the NVD data, likely due to incomplete scoring. Based on the vulnerability characteristics, a reasonable CVSS v3.1 vector would be:

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

• Attack Vector (AV): Network – the endpoint is accessible over the network.
• Attack Complexity (AC): Low – no special conditions required.
• Privileges Required (PR): None – no authentication needed to exploit the IDOR.
• User Interaction (UI): None – no user action required.
• Scope (S): Unchanged – the vulnerable component and the affected data are in the same security authority.
• Confidentiality (C): High – full access to other customers' ticket data.
• Integrity (I): None – no data modification possible via this vector.
• Availability (A): None – no impact on availability.

Threat Level: High. The vulnerability is trivial to exploit (simple parameter manipulation) and can lead to mass data exfiltration of customer support tickets, which may contain PII, credentials, or internal business information.

Deep Dive & Mechanics

The vulnerability is a classic IDOR in the /admin/ticket_a4.php endpoint. The application uses the id parameter to fetch and display ticket details from the database. The code likely performs a query similar to:

SELECT * FROM tickets WHERE id = $_GET['id'];

Without verifying that the authenticated user (or session) has permission to view that specific ticket. This allows an attacker to iterate through numeric id values (e.g., ?id=1, ?id=2, etc.) and retrieve all tickets in the system.

The attack flow:

1. Attacker identifies the vulnerable endpoint: /admin/ticket_a4.php.
2. Attacker sends a GET request with a manipulated id parameter.
3. The server returns the ticket data without authorization checks.
4. Attacker can script this to dump all tickets.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is presumed to be:

Vulnerable (PHP):

<?php
$id = $_GET['id'];
$query = "SELECT * FROM tickets WHERE id = $id";
$result = mysqli_query($conn, $query);
$ticket = mysqli_fetch_assoc($result);
echo json_encode($ticket);
?>

Patched (Hypothetical):

<?php
session_start();
if (!isset($_SESSION['user_id'])) {
    die("Unauthorized");
}
$id = intval($_GET['id']);
$user_id = $_SESSION['user_id'];
$query = "SELECT * FROM tickets WHERE id = $id AND customer_id = $user_id";
$result = mysqli_query($conn, $query);
if (mysqli_num_rows($result) == 0) {
    die("Access denied");
}
$ticket = mysqli_fetch_assoc($result);
echo json_encode($ticket);
?>

The patched version adds session authentication and a parameterized query with an authorization check (ensuring the ticket belongs to the current user).

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Access to a target running Exito v8.0.
• Knowledge of the /admin/ticket_a4.php endpoint.

Exploitation Steps:

1. Reconnaissance: Identify the endpoint and confirm it accepts an id parameter.
2. Manual Testing: Send a request with id=1 and observe the response.

   curl -v "http://target.com/admin/ticket_a4.php?id=1"
   

3. Automated Dump: Use a script to iterate through IDs.

   for i in $(seq 1 1000); do
       curl -s "http://target.com/admin/ticket_a4.php?id=$i" >> dump.json
   done
   

4. Data Extraction: Parse the JSON output to extract sensitive information.

No public exploit code is available. The above is a generic exploitation technique.

Blue Team (Detection & Defense)

Detection:

• Monitor for sequential or rapid requests to /admin/ticket_a4.php with varying id parameters.
• Alert on requests to this endpoint from unauthenticated sessions or IPs that do not match expected user behavior.

Defense:

• Implement proper authentication and authorization checks on all endpoints.
• Use parameterized queries to prevent SQL injection (though not the primary issue here).
• Apply rate limiting on the /admin/ticket_a4.php endpoint.
• Consider using a Web Application Firewall (WAF) to block anomalous parameter patterns.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Repeated GET requests to /admin/ticket_a4.php?id=[0-9]+ from a single IP.
  • Unusual volume of requests to the endpoint (e.g., >100 requests in 5 minutes).
• File IOCs:
  • Log entries showing id parameter values in sequential order.
  • Presence of large JSON files containing ticket data on attacker-controlled systems.
• Behavioral IOCs:
  • Access to /admin/ticket_a4.php without prior authentication or session cookies.

Detection Engineering

YARA Rule

rule Detect_Exito_IDOR_Exploit {
    meta:
        description = "Detects exploitation attempts of CVE-2025-41020 in Exito v8.0"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-41020"
    strings:
        $endpoint = "/admin/ticket_a4.php"
        $id_param = "id="
        $sequential = /id=\d+/ nocase
    condition:
        $endpoint and $id_param and #sequential > 5
}

Sigma Rule

title: CVE-2025-41020 - Exito IDOR Exploitation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects sequential requests to the vulnerable endpoint
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "/admin/ticket_a4.php?id="
    condition: selection
    timeframe: 5m
    aggregation:
        field: c-ip
        condition: gt 50
falsepositives:
    - Legitimate support staff viewing multiple tickets
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-41020 - Exito IDOR Exploitation Attempt"; flow:to_server; content:"/admin/ticket_a4.php"; http_uri; content:"id="; http_uri; pcre:"/id=\d+/"; threshold: type both, track by_src, count 50, seconds 300; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the application if possible until a patch is applied.
2. Implement a WAF rule to block requests to /admin/ticket_a4.php with suspicious id patterns.
3. Audit access logs for signs of exploitation.

Long-term Fix:

• The vendor (Sergestec) must release a patch that adds proper authorization checks. In the interim, developers can:
  • Add session-based authentication to the endpoint.
  • Validate that the id parameter belongs to the authenticated user.
  • Use parameterized queries to prevent SQL injection.
• Consider rewriting the application with a secure framework that enforces access controls.

Workaround:

• Disable the /admin/ticket_a4.php endpoint if not essential.
• Restrict access to the /admin/ directory via .htaccess or firewall rules.

Valters IT