CVE-2020-24571: NexusDB Path Traversal Vulnerability

CVE-2020-24571 Overview

CVE-2020-24571 is a directory traversal vulnerability affecting NexusQA NexusDB before version 4.50.23. This vulnerability allows remote attackers to read arbitrary files from the server by exploiting improper input validation in file path handling. By using ../ sequences in requests, an attacker can traverse outside the intended directory structure and access sensitive files on the system.

Critical Impact

Remote attackers can read arbitrary files from affected NexusDB servers without authentication, potentially exposing sensitive configuration files, database contents, and system credentials.

Affected Products

• NexusDB versions prior to 4.50.23
• NexusQA NexusDB database server installations

Discovery Timeline

• 2020-08-21 - CVE-2020-24571 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-24571

Vulnerability Analysis

This directory traversal vulnerability (CWE-22) exists in NexusDB's file handling mechanisms. The vulnerability occurs when the application fails to properly sanitize user-supplied input containing path traversal sequences. When processing file requests, NexusDB does not adequately validate or normalize file paths, allowing attackers to escape the web root or designated directories.

The network-accessible nature of this vulnerability means attackers can exploit it remotely without requiring authentication or user interaction. The impact is primarily focused on confidentiality, as attackers can read files but cannot modify or delete them through this specific vulnerability.

Root Cause

The root cause of CVE-2020-24571 lies in insufficient input validation within NexusDB's file access routines. The application fails to properly sanitize file path parameters, allowing directory traversal sequences such as ../ to be processed. This enables path manipulation that breaks out of the intended directory context.

Proper path canonicalization and validation against a whitelist of allowed directories were not implemented, enabling this classic path traversal attack pattern.

Attack Vector

The attack vector for this vulnerability is network-based. An attacker can craft malicious HTTP requests containing ../ sequences in file path parameters to traverse the directory structure. By chaining multiple traversal sequences (e.g., ../../../etc/passwd on Unix systems or ..\..\..\windows\win.ini on Windows), attackers can access sensitive system files outside the application's intended directory scope.

The exploitation requires no privileges or user interaction, making it trivial to exploit once the vulnerable service is identified. The attacker needs only network access to the NexusDB server to execute this attack.

Detection Methods for CVE-2020-24571

Indicators of Compromise

• HTTP requests containing ../ or ..\\ sequences in URL paths or parameters targeting NexusDB services
• Unusual file access patterns in NexusDB server logs, particularly requests for system files like /etc/passwd, win.ini, or configuration files
• Network traffic showing repeated path traversal attempts against NexusDB endpoints
• Access logs indicating successful retrieval of files outside the web root directory

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns (../, ..\\, URL-encoded variants like %2e%2e%2f)
• Configure intrusion detection systems (IDS) to alert on path traversal signatures targeting NexusDB server ports
• Deploy SentinelOne Singularity Platform for endpoint protection with behavioral analysis to detect anomalous file access patterns
• Monitor NexusDB application logs for requests containing directory traversal sequences

Monitoring Recommendations

• Enable verbose logging on NexusDB servers and forward logs to a SIEM for centralized analysis
• Implement file integrity monitoring (FIM) on sensitive system files to detect unauthorized read access
• Configure alerts for network traffic anomalies targeting NexusDB services, particularly those containing encoded path traversal patterns
• Use SentinelOne's threat intelligence feeds to identify known exploitation attempts against this vulnerability

How to Mitigate CVE-2020-24571

Immediate Actions Required

• Upgrade NexusDB to version 4.50.23 or later immediately to address this vulnerability
• Restrict network access to NexusDB servers using firewall rules, limiting connections to trusted IP addresses only
• Implement a web application firewall (WAF) with rules to block path traversal attempts
• Review access logs for signs of prior exploitation attempts and investigate any suspicious activity

Patch Information

NexusDB has released a fix in version 4.50.23 that addresses this directory traversal vulnerability. Organizations should upgrade to this version or later to remediate CVE-2020-24571. For detailed information about the fix, refer to the NexusDB Bug Report #2371.

Workarounds

• Deploy a reverse proxy or WAF in front of NexusDB to filter malicious requests containing path traversal sequences
• Implement network segmentation to isolate NexusDB servers from untrusted networks
• Configure file system permissions to limit the service account's access to only necessary directories
• If upgrading is not immediately possible, consider temporarily restricting external network access to the NexusDB service until the patch can be applied

# Example WAF rule to block path traversal attempts (ModSecurity)
SecRule REQUEST_URI "../" "id:1001,phase:1,deny,status:403,msg:'Path Traversal Attempt Detected'"
SecRule REQUEST_URI "\.\./" "id:1002,phase:1,deny,status:403,msg:'Path Traversal Attempt Detected'"
SecRule ARGS "../" "id:1003,phase:2,deny,status:403,msg:'Path Traversal in Parameter'"