CVE-2025-56396

Executive Summary

CVE-2025-56396 is a privilege escalation vulnerability discovered in Ruoyi version 4.8.1. The flaw allows an authenticated attacker to gain escalated privileges by exploiting a logic error where the owning department is granted higher rights than the active user. This vulnerability can lead to unauthorized access to sensitive data and administrative functions. No public proof-of-concept (PoC) or exploit code is currently available, and no official patch has been released. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild at this time.

Supply Chain & Package Security

Ruoyi is a Java-based open-source framework. This vulnerability does not directly affect NPM, PyPI, Go, or Ruby packages. However, organizations using Ruoyi should verify the integrity of their deployment and monitor for any unofficial patches or updates.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder. Based on the vulnerability description, a reasonable assessment would be:

• Attack Vector (AV): Network (N) – The attacker must be authenticated to the application.
• Attack Complexity (AC): Low (L) – The exploit requires no special conditions.
• Privileges Required (PR): Low (L) – The attacker needs a valid user account.
• User Interaction (UI): None (N) – No user interaction is required.
• Scope (S): Changed (C) – The vulnerability allows the attacker to gain higher privileges than originally granted.
• Confidentiality (C): High (H) – Full access to sensitive data.
• Integrity (I): High (H) – Ability to modify data.
• Availability (A): High (H) – Potential to disrupt services.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Estimated Base Score: 9.9 (Critical)

Deep Dive & Mechanics

The vulnerability lies in the authorization logic of Ruoyi 4.8.1. The system incorrectly handles department-level permissions, allowing a user to inherit or assume the privileges of their owning department. This means a low-privileged user can perform actions that should only be available to users in higher roles (e.g., admin) if their department has those rights.

Root Cause: The permission check does not properly validate that the active user's role matches the department's role. Instead, it grants the department's highest privileges to any user within that department.

Attack Scenario:

1. An attacker gains access to a low-privileged user account (e.g., via phishing or credential stuffing).
2. The attacker navigates to a sensitive function (e.g., user management, system configuration).
3. The application checks the user's department and grants the department's privileges, bypassing the user's actual role.
4. The attacker can now perform administrative actions.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical fix based on common privilege escalation patterns.

Vulnerable Code (Ruoyi 4.8.1):

// Vulnerable: Grants department-level privileges without checking user role
public boolean hasPermission(String permission) {
    User user = getCurrentUser();
    Department dept = user.getDepartment();
    // Incorrectly uses department's role
    return dept.getRole().hasPermission(permission);
}

Patched Code (Hypothetical Fix):

// Patched: Checks user's own role, not just department
public boolean hasPermission(String permission) {
    User user = getCurrentUser();
    // Correctly uses user's role
    return user.getRole().hasPermission(permission);
}

Exploitation & Lab Setup

Red Team

Since no public exploit code is available, a manual exploitation approach is described.

Prerequisites:

• A valid low-privileged user account on a Ruoyi 4.8.1 instance.
• Network access to the application.

Steps:

1. Log in with the low-privileged account.
2. Identify a sensitive endpoint (e.g., /system/user/list).
3. Send a request to that endpoint with the session cookie.
4. Observe if the response includes data that should be restricted (e.g., admin user list).

Example Request:

GET /system/user/list HTTP/1.1
Host: target.com
Cookie: JSESSIONID=lowprivsession

Expected Outcome: The server returns data that should only be accessible to administrators.

Blue Team

Detection:

• Monitor for unusual access patterns, especially low-privileged users accessing admin endpoints.
• Log all permission checks and flag anomalies.

Hunting Query (Splunk):

index=web_logs sourcetype=access_combined
| search uri="/system/*" user_role="user"
| stats count by user, uri
| where count > 10

Indicators of Compromise (IOCs)

• Log Entries: Repeated access to /system/* endpoints by non-admin users.
• Session Anomalies: A single user session accessing both low-privilege and high-privilege resources.
• Network Traffic: Unusual API calls to /system/user/update or /system/config from low-privilege accounts.

Detection Engineering

YARA Rule

rule Detect_Ruoyi_PrivEsc_CVE_2025_56396 {
    meta:
        description = "Detects potential exploitation of CVE-2025-56396 in Ruoyi 4.8.1"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "unknown"
    strings:
        $s1 = "/system/user/list" ascii wide nocase
        $s2 = "/system/role" ascii wide nocase
        $s3 = "department" ascii wide nocase
    condition:
        any of ($s*) and filesize < 10KB
}

Sigma Rule

title: Ruoyi Privilege Escalation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to exploit CVE-2025-56396 by low-privilege users accessing admin endpoints
author: Valters IT
date: 2025/04/10
logsource:
    category: web
    product: ruoyi
detection:
    selection:
        uri|startswith: '/system/'
        user_role: 'user'
    condition: selection
falsepositives:
    - Legitimate admin users with misconfigured roles
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"Ruoyi Privilege Escalation Attempt"; flow:to_server,established; content:"/system/"; http_uri; nocase; content:"user_role=user"; http_cookie; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Restrict access to sensitive endpoints using network-level controls (e.g., VPN, IP whitelisting).
2. Code Fix: Update the permission check logic to validate the user's role, not just the department's role.
3. Workaround: Manually audit and adjust department permissions to ensure no department has higher privileges than necessary.
4. Monitoring: Enable detailed logging for all permission checks and set up alerts for anomalies.
5. Patch: Monitor the official Ruoyi repository for a security patch and apply it as soon as available.

Valters IT
Securing Digital Frontiers