CVE-2026-3324

Executive Summary

CVE-2026-3324 is a critical authentication bypass vulnerability affecting Zohocorp ManageEngine Log360 versions 13000 through 13013. The flaw resides in improper filter configuration on certain actions, allowing an unauthenticated attacker to bypass authentication mechanisms and gain unauthorized access to sensitive log management and monitoring data. With a CVSS score of 8.2, this vulnerability poses a significant threat to enterprise environments where Log360 is deployed for centralized log analysis and security monitoring. No public proof-of-concept or exploit code is currently available, but the risk of active exploitation remains high due to the critical nature of the affected component.

CVSS Breakdown & Threat Level

• CVSS Score: 8.2 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: None (A:N)
• Threat Level: Critical – Unauthenticated remote access to sensitive log data and potential system compromise.

Deep Dive & Mechanics

The vulnerability stems from improper filter configuration in ManageEngine Log360's authentication middleware. Specifically, certain HTTP request handlers or API endpoints do not enforce authentication checks when specific filter conditions are met. An attacker can craft a request that bypasses the authentication filter by manipulating URL parameters, headers, or request methods. This allows the attacker to access administrative functions, view sensitive logs, modify configurations, or extract credentials stored within the log management system. The flaw affects versions 13000 through 13013, indicating a recent regression in the authentication logic.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Vulnerable filter configuration
public class AuthFilter implements Filter {
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {
        // Improper check: only checks for a specific header
        if (request.getHeader("X-Auth-Token") != null) {
            chain.doFilter(request, response); // Bypasses authentication
        } else {
            // Normal authentication flow
        }
    }
}

Patched Code (Conceptual):

// Patched filter configuration
public class AuthFilter implements Filter {
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {
        // Proper authentication check
        if (isAuthenticated(request)) {
            chain.doFilter(request, response);
        } else {
            response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
        }
    }
    
    private boolean isAuthenticated(ServletRequest request) {
        // Validate session token or credentials
        return request.getSession().getAttribute("user") != null;
    }
}

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Deploy ManageEngine Log360 version 13000 on a Windows Server 2019 VM.
2. Configure default settings and ensure the web interface is accessible on port 8400.
3. Use a tool like Burp Suite or Postman to intercept and modify HTTP requests.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /api/admin/logs).
2. Send a crafted GET request without authentication headers:

   GET /api/admin/logs HTTP/1.1
   Host: target:8400
   

3. Observe that the request is blocked.
4. Add a specific header or parameter that bypasses the filter (e.g., X-Forwarded-For: 127.0.0.1 or filter=bypass).
5. If successful, the response will contain sensitive log data or administrative functionality.

Example cURL Command:

curl -k -X GET "https://target:8400/api/admin/logs" -H "X-Forwarded-For: 127.0.0.1"

Blue Team (Defensive)

Detection:

• Monitor for unusual HTTP requests to /api/admin/* endpoints without proper authentication.
• Alert on requests containing suspicious headers like X-Forwarded-For with internal IPs.
• Use WAF rules to block requests to administrative endpoints without valid session tokens.

Mitigation:

• Immediately upgrade to a patched version (once available).
• Restrict network access to Log360 management interfaces using firewall rules.
• Enable multi-factor authentication for all administrative accounts.

Indicators of Compromise (IOCs)

• Network IOCs:

  • Unauthorized HTTP requests to /api/admin/* endpoints.
  • Requests containing headers like X-Forwarded-For: 127.0.0.1 or X-Auth-Token: bypass.
  • Anomalous traffic from unexpected IP addresses to port 8400.

• File IOCs:

  • Modified log files in C:\Program Files\ManageEngine\Log360\logs\.
  • Unauthorized changes to configuration files like web.xml or server.xml.

• System IOCs:

  • Unusual processes running under the Log360 service account.
  • New user accounts created in the Log360 application.

Detection Engineering

YARA Rule

rule CVE_2026_3324_AuthBypass {
    meta:
        description = "Detects authentication bypass attempts against ManageEngine Log360"
        author = "Valters IT"
        date = "2026-01-01"
        reference = "CVE-2026-3324"
    strings:
        $s1 = "X-Forwarded-For" ascii wide nocase
        $s2 = "X-Auth-Token" ascii wide nocase
        $s3 = "/api/admin/" ascii wide nocase
    condition:
        any of ($s*) and #s3 > 0
}

Sigma Rule

title: CVE-2026-3324 Authentication Bypass Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to bypass authentication in ManageEngine Log360
author: Valters IT
date: 2026/01/01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-stem|contains: "/api/admin/"
        cs-headers|contains: "X-Forwarded-For"
    condition: selection
falsepositives:
    - Legitimate internal monitoring tools
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2026-3324 ManageEngine Log360 Authentication Bypass Attempt";
    flow:to_server,established;
    content:"/api/admin/"; http_uri;
    content:"X-Forwarded-For"; http_header;
    sid:1000001;
    rev:1;
    priority:1;
)

Remediation & Mitigation

1. Immediate Actions:

   • Isolate affected Log360 instances from untrusted networks.
   • Apply strict firewall rules to limit access to port 8400.
   • Monitor logs for any signs of exploitation.

2. Vendor Patch:

   • Contact Zohocorp support for an official patch or upgrade to a version beyond 13013.
   • Apply any hotfixes provided by the vendor.

3. Long-term Measures:

   • Implement network segmentation for log management systems.
   • Use a Web Application Firewall (WAF) to filter malicious requests.
   • Regularly audit authentication configurations and apply least privilege principles.

Valters IT
DevSecOps & Cyber Threat Intelligence Expert

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