CVE-2025-20055: STEALTHONE Network Storage RCE Flaw

CVE-2025-20055 Overview

CVE-2025-20055 is a critical OS command injection vulnerability affecting STEALTHONE D220/D340 network storage servers manufactured by Y'S Corporation. This vulnerability allows attackers with network access to the affected devices to execute arbitrary operating system commands, potentially leading to complete system compromise.

OS command injection vulnerabilities occur when user-supplied input is passed directly to system shell commands without proper sanitization. In the case of CVE-2025-20055, the vulnerability exists in the network storage server's web interface or management functionality, enabling remote attackers to inject malicious commands that execute with the privileges of the underlying server process.

Critical Impact

Unauthenticated remote attackers can execute arbitrary OS commands on vulnerable STEALTHONE network storage servers, potentially compromising stored data, establishing persistence, or pivoting to other network resources.

Affected Products

• Y'S Corporation STEALTHONE D220 Network Storage Server
• Y'S Corporation STEALTHONE D340 Network Storage Server

Discovery Timeline

• 2025-01-14 - CVE-2025-20055 published to NVD
• 2025-01-14 - Last updated in NVD database

Technical Details for CVE-2025-20055

Vulnerability Analysis

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS command injection. The flaw exists because the affected STEALTHONE network storage servers fail to properly validate and sanitize user input before incorporating it into operating system commands.

Network-attached storage (NAS) devices like the STEALTHONE D220/D340 typically expose web-based management interfaces that allow administrators to configure storage shares, user accounts, and system settings. When these interfaces construct shell commands using unsanitized user input, attackers can inject shell metacharacters and additional commands that execute on the underlying operating system.

The vulnerability requires no authentication and can be exploited remotely over the network. Successful exploitation grants attackers the ability to execute commands with the same privileges as the web server or management process, which often runs with elevated permissions on embedded storage devices.

Root Cause

The root cause of CVE-2025-20055 is improper input validation in the STEALTHONE D220/D340 firmware. User-controlled input is passed to system shell functions without adequate sanitization of shell metacharacters such as semicolons (;), pipes (|), backticks (`), and command substitution sequences ($()).

This allows attackers to break out of the intended command context and append or inject additional commands. The lack of input validation suggests that the vulnerable code directly concatenates user input into command strings passed to functions like system(), exec(), or shell interpreters.

Attack Vector

The attack vector for CVE-2025-20055 is network-based, requiring no privileges or user interaction. An attacker with network access to the vulnerable STEALTHONE device's management interface can craft malicious requests containing OS command injection payloads.

Typical exploitation involves identifying input fields or parameters that are processed by backend shell commands. The attacker then submits specially crafted input containing shell metacharacters followed by malicious commands. When the server processes this input without sanitization, the injected commands execute on the underlying operating system.

Given that NAS devices often contain sensitive business data and may have network access to multiple systems, successful exploitation could lead to data exfiltration, ransomware deployment, or lateral movement within the organization's network.

For detailed technical information about this vulnerability, refer to the JVN Vulnerability Report.

Detection Methods for CVE-2025-20055

Indicators of Compromise

• Unexpected outbound network connections from STEALTHONE storage devices to external IP addresses
• Unusual process execution or shell commands in device logs
• Creation of unexpected files or user accounts on the storage device
• Anomalous CPU or memory utilization on the NAS device
• Web server logs containing suspicious characters such as ;, |, $(), or backticks in request parameters

Detection Strategies

• Monitor network traffic to and from STEALTHONE devices for unusual patterns or connections to known malicious infrastructure
• Implement web application firewall (WAF) rules to detect and block command injection attempts targeting NAS management interfaces
• Deploy network intrusion detection systems (IDS) with signatures for OS command injection patterns
• Review access logs for the STEALTHONE management interface for suspicious requests or unauthorized access attempts

Monitoring Recommendations

• Enable comprehensive logging on STEALTHONE devices and forward logs to a centralized SIEM for analysis
• Establish baseline network behavior for storage devices and alert on deviations
• Monitor for DNS queries or connections to suspicious domains originating from storage infrastructure
• Implement file integrity monitoring on critical storage device configuration files

How to Mitigate CVE-2025-20055

Immediate Actions Required

• Restrict network access to STEALTHONE D220/D340 management interfaces to trusted administrator IP addresses only
• Place vulnerable devices behind a firewall and disable direct internet access to management interfaces
• Review device logs for evidence of exploitation attempts or compromise
• Apply firmware updates from Y'S Corporation as soon as they become available

Patch Information

Y'S Corporation has released firmware updates to address this vulnerability. Organizations using STEALTHONE D220/D340 devices should immediately visit the StealthOne Product Information page to download and apply the latest firmware version.

Refer to the JVN Vulnerability Report for additional details regarding affected versions and remediation guidance.

Workarounds

• Implement network segmentation to isolate STEALTHONE devices from untrusted networks and limit exposure
• Configure access control lists (ACLs) on network switches and firewalls to restrict management interface access to specific administrator workstations
• Disable any unnecessary services or features on the storage devices that may expose additional attack surface
• Consider deploying a reverse proxy with input validation in front of the management interface as an additional layer of protection

# Example firewall rule to restrict management access (iptables)
# Replace 192.168.1.100 with your STEALTHONE device IP
# Replace 192.168.1.50 with trusted admin workstation IP
iptables -A INPUT -d 192.168.1.100 -p tcp --dport 443 -s 192.168.1.50 -j ACCEPT
iptables -A INPUT -d 192.168.1.100 -p tcp --dport 443 -j DROP
iptables -A INPUT -d 192.168.1.100 -p tcp --dport 80 -s 192.168.1.50 -j ACCEPT
iptables -A INPUT -d 192.168.1.100 -p tcp --dport 80 -j DROP