CVE-2024-0988: Kuerp Authentication Bypass Vulnerability

CVE-2024-0988 Overview

A critical authentication bypass vulnerability was discovered in Sichuan Yougou Technology KuERP up to version 1.0.4. This vulnerability affects the checklogin function within the file /application/index/common.php. Through manipulation of the App_User_id and App_user_Token arguments, an attacker can bypass authentication controls, potentially gaining unauthorized access to the ERP system. The exploit has been publicly disclosed, and the vendor was contacted but did not respond to the disclosure.

Critical Impact

This authentication bypass vulnerability allows unauthenticated attackers to gain unauthorized access to the KuERP system over the network, potentially compromising confidentiality, integrity, and availability of sensitive business data.

Affected Products

• Sichuan Yougou Technology KuERP up to version 1.0.4
• KuERP Project KuERP (all versions through 1.0.4)

Discovery Timeline

• 2024-01-29 - CVE-2024-0988 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-0988

Vulnerability Analysis

This vulnerability is classified as CWE-287 (Improper Authentication), indicating a fundamental flaw in how the KuERP application validates user credentials and session tokens. The checklogin function in /application/index/common.php fails to properly authenticate users, allowing attackers to manipulate authentication parameters to bypass security controls entirely.

ERP systems like KuERP typically contain sensitive business information including financial records, customer data, inventory details, and employee information. An authentication bypass in such a system represents a severe security risk, as it could allow unauthorized parties to access, modify, or exfiltrate this critical business data.

The vulnerability can be exploited remotely without any privileges or user interaction, making it particularly dangerous for internet-exposed KuERP installations. The attack does not require specialized knowledge or tools, and exploitation has been publicly documented.

Root Cause

The root cause of this vulnerability lies in improper validation of the App_User_id and App_user_Token parameters within the checklogin function. The application fails to adequately verify that these authentication tokens correspond to a legitimate authenticated session, allowing attackers to forge or manipulate these values to gain access.

This type of authentication bypass typically occurs when applications trust client-supplied authentication data without proper server-side validation, or when the token validation logic contains flaws that can be circumvented through parameter manipulation.

Attack Vector

The attack is network-based and can be executed without any prior authentication or user interaction. An attacker can craft malicious requests targeting the /application/index/common.php endpoint, manipulating the App_User_id and App_user_Token parameters to bypass the checklogin function's authentication checks.

The vulnerability mechanism involves crafting specific values for the authentication parameters that the checklogin function fails to properly validate. Technical details are available in the Zhao Jin Note Share advisory and the VulDB entry #252253.

Detection Methods for CVE-2024-0988

Indicators of Compromise

• Unusual authentication patterns or access to KuERP from unexpected IP addresses or geolocations
• Suspicious requests to /application/index/common.php with abnormal App_User_id or App_user_Token values
• Unauthorized account access or privilege escalation within the ERP system
• Unexpected data access patterns or bulk data retrieval from KuERP

Detection Strategies

• Monitor web server access logs for requests to /application/index/common.php with malformed or suspicious authentication parameters
• Implement anomaly detection for authentication events, particularly failed authentication attempts followed by successful access
• Deploy Web Application Firewall (WAF) rules to inspect and filter requests with suspicious authentication token patterns
• Review KuERP application logs for unauthorized access attempts or privilege escalation events

Monitoring Recommendations

• Enable detailed logging for all authentication events within KuERP
• Configure alerting for multiple authentication failures from the same source IP followed by successful login
• Implement session monitoring to detect unusual session creation patterns
• Deploy SentinelOne Singularity Platform for endpoint-level visibility and real-time threat detection on servers hosting KuERP

How to Mitigate CVE-2024-0988

Immediate Actions Required

• Restrict network access to KuERP installations using firewall rules or network segmentation
• Implement additional authentication layers such as VPN or multi-factor authentication (MFA) before allowing access to KuERP
• Audit user accounts and access logs for signs of unauthorized access
• Consider taking the application offline until remediation is applied if it handles sensitive data

Patch Information

At the time of disclosure, the vendor (Sichuan Yougou Technology) was contacted but did not respond. No official patch is currently available. Organizations using KuERP should contact the vendor directly for remediation options or consider alternative ERP solutions with active security support.

For additional technical details and vulnerability tracking, refer to VulDB entry #252253.

Workarounds

• Restrict access to KuERP to trusted internal networks only and block external access entirely
• Implement a reverse proxy or WAF with strict input validation rules for the App_User_id and App_user_Token parameters
• Add IP-based access control lists (ACLs) to limit who can access the application
• Monitor all access to the vulnerable endpoint and implement rate limiting to detect exploitation attempts

# Example: Restrict access to KuERP via iptables (limit to internal network)
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

# Example: Nginx location block to restrict access to vulnerable endpoint
# location /application/index/common.php {
#     allow 192.168.1.0/24;
#     deny all;
# }