CVE-2020-5847: Unraid RCE Vulnerability

CVE-2020-5847 Overview

CVE-2020-5847 is a Remote Code Execution (RCE) vulnerability affecting Unraid through version 6.8.0. This vulnerability allows unauthenticated remote attackers to execute arbitrary code on vulnerable Unraid systems, potentially gaining complete control over the NAS server and its data.

Critical Impact

This vulnerability is actively exploited in the wild and has been added to CISA's Known Exploited Vulnerabilities (KEV) catalog. Unauthenticated attackers can achieve remote code execution as root on vulnerable Unraid servers.

Affected Products

• Unraid versions through 6.8.0

Discovery Timeline

• 2020-03-16 - CVE-2020-5847 published to NVD
• 2025-10-31 - Last updated in NVD database

Technical Details for CVE-2020-5847

Vulnerability Analysis

This vulnerability enables unauthenticated remote code execution on Unraid NAS systems running versions up to and including 6.8.0. The attack can be launched over the network without requiring any user interaction or prior authentication, making it particularly dangerous for Internet-exposed Unraid instances. According to the SysDream security analysis, successful exploitation results in code execution with root privileges, giving attackers complete control over the system.

The vulnerability has been confirmed to be actively exploited in the wild and is listed in the CISA Known Exploited Vulnerabilities catalog, emphasizing the urgency of patching affected systems.

Root Cause

The vulnerability stems from improper input validation or access control mechanisms in Unraid's web management interface. The specific implementation flaw allows remote attackers to bypass authentication and inject malicious commands that execute with elevated privileges on the underlying system.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can target the Unraid web management interface to exploit the vulnerability. Given the nature of NAS systems often being accessible on local networks or sometimes exposed to the Internet for remote management, the attack surface can be significant. The vulnerability is associated with an authentication bypass component (CVE-2020-5849), which when chained together allows complete unauthenticated remote code execution as root.

For detailed technical analysis and exploitation methodology, refer to the Packet Storm Security advisory and the SysDream CVE-2020-5847 analysis.

Detection Methods for CVE-2020-5847

Indicators of Compromise

• Unexpected processes running with root privileges on Unraid servers
• Suspicious outbound network connections from Unraid NAS systems
• Unauthorized modifications to system files or configuration
• Anomalous web server logs indicating exploitation attempts against the management interface
• Presence of unknown user accounts or SSH keys on the system

Detection Strategies

• Monitor Unraid web management interface access logs for unusual request patterns or malformed requests
• Implement network intrusion detection rules to identify exploitation attempts targeting CVE-2020-5847
• Deploy endpoint detection and response (EDR) solutions to detect post-exploitation activities
• Review system processes for unexpected command execution originating from web server processes

Monitoring Recommendations

• Enable comprehensive logging on Unraid systems and forward logs to a centralized SIEM
• Monitor for unauthorized file system changes, especially in system directories
• Set up alerts for new outbound connections from Unraid servers to unknown destinations
• Regularly audit running processes and compare against known-good baselines

How to Mitigate CVE-2020-5847

Immediate Actions Required

• Update Unraid to version 6.8.1 or later immediately
• Isolate vulnerable Unraid systems from untrusted networks
• Do not expose the Unraid web management interface directly to the Internet
• Implement network segmentation to limit access to NAS systems
• Review system logs for signs of prior exploitation

Patch Information

Unraid has released updates addressing this vulnerability. Users should update to version 6.8.1 or the latest available version. Security announcements and update information are available on the Unraid Forum Announcements page.

Workarounds

• Place Unraid systems behind a firewall with strict access controls limiting management interface access
• Implement VPN requirements for remote access to Unraid management interfaces
• Use network access control lists (ACLs) to restrict which IP addresses can reach the management interface
• Consider disabling remote management access entirely until the system can be patched

# Network isolation example using iptables
# Restrict access to Unraid management port (typically 80/443) to trusted IPs only
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP