CVE-2025-3567: Echo Community System Auth Bypass Flaw

CVE-2025-3567 Overview

CVE-2025-3567 is an improper authorization vulnerability [CWE-266] in the veal98 Echo open-source community system version 4.2. The flaw resides in the preHandle function of src/main/java/com/greate/community/controller/interceptor/LoginTicketInterceptor.java, part of the Ticket Handler component. An unauthenticated or low-privileged remote attacker can manipulate the ticket handling logic to bypass authorization checks. The exploit details have been publicly disclosed, increasing the likelihood of opportunistic abuse against exposed instances.

Critical Impact

Remote attackers can bypass authorization controls in the Echo community platform, gaining access to protected resources without proper credentials.

Affected Products

• veal98 Echo (小牛肉 开源社区系统) version 4.2
• Component: Ticket Handler (LoginTicketInterceptor.java)
• Function: preHandle

Discovery Timeline

• 2025-04-14 - CVE-2025-3567 published to the National Vulnerability Database (NVD)
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3567

Vulnerability Analysis

The Echo community platform uses a Spring MVC interceptor pattern to enforce session-based authorization. The LoginTicketInterceptor.preHandle method is responsible for validating login tickets before requests reach protected controller endpoints. The vulnerable implementation performs insufficient validation of the authorization state associated with the ticket, allowing requests to proceed to resources the user should not be able to access.

Because the vulnerability is network-reachable and requires only low privileges, an attacker with a basic account, or one able to obtain a valid ticket cookie, can invoke restricted functionality. The public disclosure of exploitation details raises the operational risk for internet-exposed deployments.

The EPSS score is 0.318% (24th percentile), indicating limited but non-zero probability of near-term exploitation activity.

Root Cause

The root cause is improper authorization [CWE-266] within the interceptor logic. The preHandle function grants access based on the presence of a ticket rather than fully verifying the ticket owner's permissions relative to the requested resource. This design conflates authentication with authorization, a pattern that violates the principle of least privilege.

Attack Vector

Exploitation is remote and requires no user interaction. An attacker sends crafted HTTP requests to endpoints protected by LoginTicketInterceptor. Because the interceptor fails to enforce granular authorization, the backend controllers execute requested actions as though they were properly authorized. This can expose user data, administrative functions, or moderation controls depending on the targeted endpoint.

The vulnerability manifests entirely in server-side Java code. Refer to the GitHub CVE Exploit Documentation and the VulDB Entry #304608 for technical proof-of-concept details.

Detection Methods for CVE-2025-3567

Indicators of Compromise

• Unexpected HTTP 200 responses to endpoints normally restricted to authenticated administrators or resource owners.
• Access log entries showing low-privilege user IDs invoking privileged controller paths handled by LoginTicketInterceptor.
• Anomalous ticket cookie reuse patterns across multiple source IP addresses in short time windows.

Detection Strategies

• Instrument the preHandle method with request-level audit logging to record ticket owner, target URL, and resulting authorization decision.
• Correlate application logs with web server logs to identify sessions accessing resources outside their expected scope.
• Deploy web application firewall rules that flag repeated requests to sensitive Echo endpoints from unauthenticated or newly created accounts.

Monitoring Recommendations

• Alert on privilege boundary violations where a user account accesses resources belonging to another user or role.
• Track rate spikes against controller endpoints protected by the Ticket Handler component.
• Retain HTTP request bodies and headers for post-incident analysis of authorization bypass patterns.

How to Mitigate CVE-2025-3567

Immediate Actions Required

• Restrict network exposure of Echo 4.2 instances by placing them behind authenticated reverse proxies or VPNs until a fix is applied.
• Audit application logs for indicators of unauthorized access to protected endpoints.
• Invalidate all active login tickets and require users to re-authenticate to reduce the window of misuse.

Patch Information

No vendor patch has been referenced in the NVD entry for CVE-2025-3567 at the time of publication. Administrators should monitor the upstream Echo project and the VulDB Report #304608 for remediation updates. Until a patch is available, apply the workarounds below and consider forking the project to implement proper authorization checks in LoginTicketInterceptor.preHandle.

Workarounds

• Modify LoginTicketInterceptor.preHandle to enforce resource-level authorization by comparing the ticket owner's user ID and role against the requested resource before returning true.
• Add a secondary interceptor or Spring Security filter that validates role-based access control on every protected endpoint.
• Disable or firewall-restrict any Echo administrative endpoints that cannot be immediately protected through code changes.

# Example: restrict Echo admin paths at the reverse proxy layer (nginx)
location ~ ^/(admin|discuss/top|discuss/delete) {
    allow 10.0.0.0/8;
    deny all;
    proxy_pass http://echo_backend;
}