CVE-2024-7742: Ltcms SSRF Vulnerability in API Endpoint

CVE-2024-7742 Overview

A Server-Side Request Forgery (SSRF) vulnerability has been identified in wanglongcn ltcms version 1.0.20. The vulnerability exists in the multiDownload function within the /api/file/multiDownload API endpoint. By manipulating the file argument, an attacker can force the server to make arbitrary requests to internal or external resources, potentially leading to unauthorized access to internal services, data exfiltration, or further exploitation of backend systems.

Critical Impact

This SSRF vulnerability allows remote attackers to exploit the multiDownload API endpoint without authentication, enabling server-side requests to arbitrary destinations. The exploit has been publicly disclosed, increasing the risk of active exploitation.

Affected Products

• ltcms version 1.0.20
• ltcms:ltcms component

Discovery Timeline

• 2024-08-13 - CVE-2024-7742 published to NVD
• 2024-08-21 - Last updated in NVD database

Technical Details for CVE-2024-7742

Vulnerability Analysis

This vulnerability is classified as CWE-918 (Server-Side Request Forgery). The SSRF flaw occurs when the multiDownload function in the ltcms content management system fails to properly validate or sanitize the file parameter before processing download requests. When a user submits a request to the /api/file/multiDownload endpoint, the application processes the provided file argument without adequate validation, allowing an attacker to specify arbitrary URLs or internal network addresses.

The vulnerability can be exploited remotely without requiring authentication. An attacker can leverage this flaw to scan internal network infrastructure, access internal services that should not be publicly accessible, retrieve sensitive configuration files, or potentially pivot to further attacks against backend systems.

Root Cause

The root cause of this vulnerability lies in insufficient input validation of the file parameter within the multiDownload function. The application directly uses user-supplied input to construct server-side requests without implementing proper URL validation, allowlist filtering, or protocol restrictions. This allows attackers to manipulate the destination of server-originated HTTP requests.

Attack Vector

The attack is network-based and can be executed remotely. An attacker crafts a malicious request to the /api/file/multiDownload API endpoint, supplying a manipulated file parameter containing an internal URL, cloud metadata endpoint, or other sensitive resource. The server then initiates a request to the attacker-specified destination and returns the response, potentially exposing internal data or services.

Common SSRF attack targets include internal services on localhost (127.0.0.1), cloud instance metadata services (169.254.169.254), internal network resources, and administrative interfaces. The vulnerability allows attackers to bypass network segmentation and firewall rules by using the vulnerable server as a proxy.

Detection Methods for CVE-2024-7742

Indicators of Compromise

• Unusual outbound requests from the web server to internal IP addresses or cloud metadata endpoints
• HTTP requests to the /api/file/multiDownload endpoint containing suspicious URL patterns in the file parameter
• Server logs showing requests to internal services (127.0.0.1, 10.x.x.x, 192.168.x.x, 169.254.169.254)
• Unexpected data retrieval patterns or responses containing internal configuration data

Detection Strategies

• Monitor web application logs for requests to /api/file/multiDownload with non-standard file paths or URL schemes
• Implement network monitoring to detect outbound connections from web servers to internal infrastructure
• Deploy Web Application Firewall (WAF) rules to detect SSRF payloads in request parameters
• Review access logs for patterns indicative of internal network scanning or metadata service access

Monitoring Recommendations

• Enable detailed logging on the ltcms application to capture all API endpoint requests with full parameter values
• Configure network intrusion detection systems to alert on internal IP address access from DMZ web servers
• Set up alerts for cloud metadata endpoint access attempts (169.254.169.254)
• Monitor for unusual DNS resolution patterns from the web server

How to Mitigate CVE-2024-7742

Immediate Actions Required

• Restrict access to the /api/file/multiDownload endpoint until a patch is available
• Implement network-level controls to prevent the web server from initiating connections to internal resources
• Deploy WAF rules to block SSRF attack patterns targeting the vulnerable endpoint
• Review and audit all requests to the affected API endpoint for signs of exploitation

Patch Information

The vendor (wanglongcn) was contacted about this vulnerability but did not respond. As of the last modification date, no official patch is available. Organizations using ltcms 1.0.20 should consider implementing the workarounds below or migrating to an alternative CMS solution until the vendor addresses this vulnerability. For additional technical details, refer to VulDB Entry #274362.

Workarounds

• Implement input validation on the file parameter to restrict accepted values to an allowlist of approved file paths
• Configure network firewall rules to prevent the web server from accessing internal IP ranges and cloud metadata services
• Use a reverse proxy with SSRF protection capabilities in front of the ltcms application
• Disable or remove the multiDownload functionality if not required for business operations
• Implement URL validation that blocks private IP ranges, localhost, and metadata service addresses

# Example iptables rules to restrict outbound connections from web server
# Block access to internal networks and cloud metadata
iptables -A OUTPUT -d 127.0.0.0/8 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 10.0.0.0/8 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 169.254.169.254/32 -m owner --uid-owner www-data -j DROP