CVE-2020-6286: SAP NetWeaver Java Path Traversal Flaw

CVE-2020-6286 Overview

CVE-2020-6286 is a path traversal vulnerability affecting the SAP NetWeaver Application Server Java (LM Configuration Wizard) component. The vulnerability stems from insufficient input path validation of certain parameters in the web service, allowing unauthenticated attackers to exploit a method to download zip files to a specific directory.

This vulnerability enables remote attackers to traverse file system paths without requiring authentication, potentially exposing sensitive configuration files and system data. The network-accessible nature of this flaw significantly increases its risk profile for organizations running affected SAP NetWeaver deployments.

Critical Impact

Unauthenticated attackers can exploit path traversal to download files from arbitrary directories, potentially exposing sensitive configuration data and system information from SAP NetWeaver installations.

Affected Products

• SAP NetWeaver Application Server Java 7.30
• SAP NetWeaver Application Server Java 7.31
• SAP NetWeaver Application Server Java 7.40
• SAP NetWeaver Application Server Java 7.50

Discovery Timeline

• July 14, 2020 - CVE-2020-6286 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-6286

Vulnerability Analysis

This path traversal vulnerability (CWE-22) exists in the LM Configuration Wizard component of SAP NetWeaver AS JAVA. The flaw allows unauthenticated attackers to manipulate file path parameters in web service requests, enabling them to navigate outside of intended directories and download zip files from arbitrary locations on the server.

The vulnerability is particularly concerning because it requires no authentication, meaning any network-accessible attacker can potentially exploit it. While the direct impact is limited to information disclosure (confidentiality breach), the exposed data could include sensitive configuration files, credentials, or other critical information that could facilitate further attacks against the SAP environment.

Root Cause

The root cause is insufficient input validation on path parameters within the LM Configuration Wizard web service. The application fails to properly sanitize user-supplied input that specifies file paths, allowing directory traversal sequences (such as ../) to escape the intended directory scope. This lack of input validation enables attackers to construct malicious requests that reference files outside the designated download directory.

Attack Vector

The attack is conducted remotely over the network by sending specially crafted HTTP requests to the vulnerable LM Configuration Wizard web service endpoint. An attacker constructs requests containing path traversal sequences in the vulnerable parameter to navigate to directories outside the intended scope.

The exploitation flow involves:

1. Identifying an exposed SAP NetWeaver AS JAVA instance with the vulnerable LM Configuration Wizard component
2. Crafting HTTP requests with malicious path parameters containing traversal sequences
3. Exploiting the file download method to retrieve zip files from arbitrary server directories
4. Analyzing retrieved files for sensitive information such as configuration data or credentials

Detection Methods for CVE-2020-6286

Indicators of Compromise

• HTTP requests to LM Configuration Wizard endpoints containing path traversal sequences (../ or URL-encoded variants like %2e%2e%2f)
• Unusual file download activity from SAP NetWeaver web services
• Access logs showing requests to configuration wizard endpoints from unexpected external IP addresses
• Evidence of zip file downloads targeting system directories outside normal application paths

Detection Strategies

• Monitor HTTP access logs for requests containing directory traversal patterns targeting SAP NetWeaver services
• Implement Web Application Firewall (WAF) rules to detect and block path traversal attempts against SAP endpoints
• Enable detailed logging on SAP NetWeaver AS JAVA to capture all LM Configuration Wizard activity
• Deploy network intrusion detection signatures for SAP-specific path traversal exploitation attempts

Monitoring Recommendations

• Configure alerts for any unauthenticated access attempts to LM Configuration Wizard web service endpoints
• Implement file integrity monitoring on sensitive SAP configuration directories
• Review SAP security audit logs regularly for signs of unauthorized file access attempts
• Monitor network traffic for large zip file transfers from SAP servers to unusual destinations

How to Mitigate CVE-2020-6286

Immediate Actions Required

• Apply the security patch referenced in SAP Support Note #2934135 immediately
• Restrict network access to LM Configuration Wizard endpoints to authorized administrative networks only
• Enable comprehensive logging on SAP NetWeaver AS JAVA to detect exploitation attempts
• Review access controls and ensure the LM Configuration Wizard is only accessible to authorized personnel

Patch Information

SAP has released a security patch addressing this vulnerability. Organizations should obtain and apply the patch from SAP Support Note #2934135. Additional information about the July 2020 security updates is available on the SAP Wiki Page Overview.

All affected versions (7.30, 7.31, 7.40, and 7.50) of SAP NetWeaver Application Server Java should be updated to incorporate this security fix.

Workarounds

• Implement network segmentation to restrict access to SAP NetWeaver AS JAVA management interfaces from untrusted networks
• Deploy a Web Application Firewall (WAF) with rules to detect and block path traversal attack patterns
• Consider disabling the LM Configuration Wizard component if not actively required for operations
• Apply strict IP-based access controls to limit who can reach the vulnerable web service endpoints

# Example: Restrict access to SAP LM Configuration Wizard using firewall rules
# Allow only trusted administrative network to access SAP management interfaces
iptables -A INPUT -p tcp --dport 50000 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 50000 -j DROP