CVE-2024-39847 Overview
CVE-2024-39847 is an XML External Entity (XXE) vulnerability affecting the SOAP endpoints in 4D server. Unauthenticated attackers can exploit a weakness in the XML parser functionality to obtain read access to files on the application server and adjacent network shares, and perform HTTP GET requests to arbitrary services. This vulnerability poses significant risks to data confidentiality and can enable further reconnaissance against internal network infrastructure.
Critical Impact
Unauthenticated remote attackers can read sensitive files from the server and perform server-side request forgery (SSRF) attacks against internal services without any authentication requirements.
Affected Products
- 4D Server (versions with vulnerable SOAP endpoint XML parsing)
Discovery Timeline
- 2026-04-30 - CVE CVE-2024-39847 published to NVD
- 2026-04-30 - Last updated in NVD database
Technical Details for CVE-2024-39847
Vulnerability Analysis
This vulnerability is classified under CWE-611 (Improper Restriction of XML External Entity Reference). The SOAP endpoints in 4D server fail to properly restrict XML external entity processing, allowing attackers to craft malicious XML payloads that reference external entities. When the vulnerable XML parser processes these payloads, it resolves the external entity references, which can include local file paths or URLs to internal services.
The attack requires no authentication, making it accessible to any network-reachable attacker. The vulnerability enables two primary attack scenarios: file disclosure through local file inclusion via XXE, and server-side request forgery through external URL entity resolution.
Root Cause
The root cause of this vulnerability lies in the insecure configuration of the XML parser used by the SOAP endpoints in 4D server. The parser does not disable external entity processing, allowing it to resolve DTD (Document Type Definition) declarations that reference external resources. This is a common misconfiguration in XML processing libraries where external entities and DTD processing are enabled by default.
Attack Vector
The attack is executed remotely over the network without requiring any user interaction or prior authentication. An attacker sends a specially crafted SOAP request containing a malicious XML document with external entity declarations. The vulnerable XML parser processes these declarations, causing the server to:
- Read local files specified in the entity declarations and return their contents in error messages or responses
- Make HTTP GET requests to arbitrary internal or external services, enabling SSRF attacks
- Access files on adjacent network shares accessible to the server
The attack does not require any special privileges and can be performed by any unauthenticated network attacker who can reach the SOAP endpoints. For detailed technical analysis, refer to the Schutzwerk Security Bulletin SA-2024-002.
Detection Methods for CVE-2024-39847
Indicators of Compromise
- Unusual SOAP requests containing DOCTYPE declarations or ENTITY definitions in XML payloads
- Server-side requests to internal IP addresses or localhost from the 4D server process
- Access to sensitive configuration files such as /etc/passwd, Windows SAM files, or application configuration files
- Unexpected outbound HTTP connections originating from the 4D server to internal network resources
Detection Strategies
- Deploy web application firewalls (WAF) with rules to detect and block XXE payloads in SOAP requests
- Monitor and analyze SOAP endpoint access logs for suspicious XML patterns including <!ENTITY, <!DOCTYPE, and SYSTEM keywords
- Implement network segmentation monitoring to detect unexpected connections from the 4D server to internal services
- Configure intrusion detection systems (IDS) with signatures for common XXE attack patterns
Monitoring Recommendations
- Enable detailed logging for all SOAP endpoint requests and responses on 4D server
- Monitor file access patterns on the server for unusual read operations to sensitive system files
- Track outbound network connections from the 4D server process to identify potential SSRF activity
- Set up alerts for XML parsing errors that may indicate exploitation attempts
How to Mitigate CVE-2024-39847
Immediate Actions Required
- Review and apply any available security updates from 4D for the affected server components
- Restrict network access to SOAP endpoints to trusted IP addresses only using firewall rules
- Implement input validation on SOAP requests to reject XML documents containing external entity declarations
- Consider temporarily disabling SOAP functionality if not required for business operations
Patch Information
Consult the 4D Company Website and the Schutzwerk Security Bulletin SA-2024-002 for the latest security advisories and patch information. Apply vendor-provided patches as soon as they become available. Ensure you are running the latest supported version of 4D server with all security updates applied.
Workarounds
- Configure the XML parser to disable external entity processing and DTD processing if configuration options are available
- Deploy a reverse proxy or web application firewall in front of the SOAP endpoints to filter malicious XML payloads
- Implement network-level access controls to limit which hosts can reach the SOAP endpoints
- Use application-level authentication to restrict access to SOAP functionality to authorized users only
# Example: Network access restriction using iptables
# Restrict SOAP endpoint access to trusted networks only
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
