CVE-2020-24571: NexusDB Path Traversal Vulnerability

CVE-2020-24571 Overview

CVE-2020-24571 is a directory traversal vulnerability in NexusQA NexusDB versions prior to 4.50.23. The flaw allows unauthenticated remote attackers to read arbitrary files on the host system by submitting crafted requests containing ../ sequences. Because NexusDB is a database engine often exposed over the network, attackers can retrieve configuration files, credentials, and other sensitive data outside the intended directory scope. The weakness is categorized as [CWE-22] Improper Limitation of a Pathname to a Restricted Directory. The EPSS score of 92.42% places this issue in the 99.7th percentile, indicating a high probability of exploitation activity.

Critical Impact

Unauthenticated network attackers can read arbitrary files from the NexusDB host, exposing credentials and sensitive configuration data.

Affected Products

• NexusQA NexusDB versions prior to 4.50.23
• Applications embedding the vulnerable NexusDB engine
• Network-exposed NexusDB server instances

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

The vulnerability resides in the file-handling logic of NexusDB versions before 4.50.23. The server fails to canonicalize or restrict user-supplied paths before resolving them on the filesystem. An attacker submits a request containing ../ traversal sequences and the server walks outside the intended data directory.

The issue requires no authentication and no user interaction. Exploitation is performed over the network against the NexusDB service. Successful requests return file contents to the attacker, breaching confidentiality of the host system.

The attack is purely read-oriented. It does not directly grant code execution or write access. However, retrieved files frequently include database credentials, application secrets, and operating system configuration that enable follow-on attacks.

Root Cause

The root cause is insufficient input validation on file path parameters. NexusDB accepts relative path components such as ../ without normalizing the resulting path or enforcing a chroot-style boundary. This matches the classic [CWE-22] pattern where dot-dot-slash sequences escape the intended directory.

Attack Vector

An attacker reaches the NexusDB network service and issues a request that references a file using traversal sequences. For example, a path parameter set to ../../../../windows/win.ini or ../../../../etc/passwd would resolve outside the data directory. The server reads the targeted file and returns its contents in the response. Refer to the NexusDB Bug Report for vendor details.

Detection Methods for CVE-2020-24571

Indicators of Compromise

• Inbound requests to NexusDB services containing ../, ..\, or URL-encoded %2e%2e%2f sequences
• Access attempts targeting sensitive system files such as /etc/passwd, /etc/shadow, or C:\Windows\win.ini
• Anomalous outbound data transfer volumes from NexusDB hosts following crafted requests
• NexusDB process reading files outside its configured database directory

Detection Strategies

• Inspect application and proxy logs for path parameters containing traversal patterns directed at NexusDB endpoints
• Deploy network signatures that flag dot-dot-slash sequences in requests to NexusDB service ports
• Correlate NexusDB file access events with the configured data directory to identify out-of-scope reads
• Alert on unauthenticated requests retrieving files with non-database extensions

Monitoring Recommendations

• Enable verbose request logging on NexusDB servers and forward logs to a centralized SIEM
• Monitor file access auditing on the host operating system for reads initiated by the NexusDB process
• Track NexusDB version inventory across the environment to identify instances below 4.50.23
• Baseline normal client query patterns and alert on deviations indicating path manipulation

How to Mitigate CVE-2020-24571

Immediate Actions Required

• Upgrade NexusDB to version 4.50.23 or later on all affected systems
• Restrict network access to NexusDB services using firewall rules and allowlists
• Audit log files for prior traversal attempts and assess potential data exposure
• Rotate any credentials or secrets stored in files reachable from the NexusDB host

Patch Information

The vendor addressed the issue in NexusDB 4.50.23. Administrators should consult the NexusDB Bug Report and apply the fixed release. No official workaround replaces the patch, and earlier branches remain vulnerable to unauthenticated file disclosure.

Workarounds

• Place NexusDB behind a reverse proxy that strips or rejects path traversal sequences
• Run the NexusDB service under a low-privilege account with filesystem access limited to required directories
• Apply host-based access controls to deny the service account read access to sensitive system files
• Isolate NexusDB instances on internal network segments not reachable from untrusted networks

# Example firewall rule restricting NexusDB access to a trusted subnet
iptables -A INPUT -p tcp --dport 16000 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 16000 -j DROP