CVE-2021-32974 – CVE-2021-32974 is a critical remote code execut... (How to Fix)

Q: What is the severity of CVE-2021-32974?

CVE-2021-32974 has a CVSS score of 9.8 (CRITICAL). CVE-2021-32974 is a critical remote code execution vulnerability in Moxa NPort IAW5000A-I/O series devices. Improper input validation in the built-in web server allows unauthenticated remote attackers to execute arbitrary commands on affected devices. Organizations using these industrial serial device servers with firmware version 2.2 or earlier are at risk.

📋 TL;DR

CVE-2021-32974 is a critical remote code execution vulnerability in Moxa NPort IAW5000A-I/O series devices. Improper input validation in the built-in web server allows unauthenticated remote attackers to execute arbitrary commands on affected devices. Organizations using these industrial serial device servers with firmware version 2.2 or earlier are at risk.

💻 Affected Systems

Products:

Moxa NPort IAW5000A-I/O series

Versions: Firmware version 2.2 and earlier

Operating Systems: Embedded firmware

Default Config Vulnerable: ⚠️ Yes

Notes: All devices with vulnerable firmware are affected regardless of configuration. The web server is enabled by default.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete device compromise allowing attacker to execute arbitrary commands, disrupt industrial operations, pivot to other network systems, and potentially cause physical damage or safety incidents.

🟠

Likely Case

Remote attacker gains full control of the device, can modify configurations, disrupt serial communications, and use the device as a foothold into industrial control networks.

🟢

If Mitigated

With proper network segmentation and access controls, impact is limited to the isolated device with no lateral movement to critical systems.

🌐 Internet-Facing: HIGH - Directly exposed devices can be exploited by any internet attacker without authentication.

🏢 Internal Only: HIGH - Even internally, any network-accessible device can be exploited by attackers who gain internal access.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires sending specially crafted HTTP requests to the web server. No authentication is required, making this trivial to exploit.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firmware version 2.3 or later

Vendor Advisory: https://www.moxa.com/en/support/product-support/security-advisory/nport-iaw5000a-io-serial-device-server-vulnerabilities

Restart Required: Yes

Instructions:

1. Download firmware version 2.3 or later from Moxa website. 2. Backup current configuration. 3. Upload new firmware via web interface. 4. Reboot device. 5. Restore configuration if needed.

🔧 Temporary Workarounds

Network Segmentation

all

Isolate affected devices in separate VLANs with strict firewall rules limiting access to authorized management systems only.

Disable Web Interface

all

If web management is not required, disable the built-in web server via device configuration.

🧯 If You Can't Patch

Implement strict network access controls to limit device access to only authorized IP addresses
Monitor network traffic to/from affected devices for suspicious HTTP requests and command execution attempts

🔍 How to Verify

Check if Vulnerable:

Check firmware version via web interface (System > System Information) or serial console. If version is 2.2 or earlier, device is vulnerable.

Check Version:

Via web interface or serial console: show version

Verify Fix Applied:

Verify firmware version is 2.3 or later after update. Test web interface functionality to ensure it still works properly.

📡 Detection & Monitoring

Log Indicators:

Unusual HTTP requests to web interface
Multiple failed login attempts followed by command execution patterns
System configuration changes from unknown sources

Network Indicators:

HTTP POST requests with command injection patterns to device web server
Unexpected outbound connections from device
Traffic to/from device on non-standard ports

SIEM Query:

source_ip=[device_ip] AND (http_method=POST AND (http_uri CONTAINS "cmd" OR http_uri CONTAINS "exec" OR http_uri CONTAINS "system"))

📊 Metadata

CVE ID: CVE-2021-32974

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-20

Published: April 1, 2022

Last Updated: November 21, 2024

🔗 References

https://www.cisa.gov/uscert/ics/advisories/icsa-21-187-01 Mitigation,Third Party Advisory,US Government Resource
https://www.moxa.com/en/support/product-support/security-advisory/nport-iaw5000a-io-serial-device-server-vulnerabilities Vendor Advisory
https://www.cisa.gov/uscert/ics/advisories/icsa-21-187-01 Mitigation,Third Party Advisory,US Government Resource
https://www.moxa.com/en/support/product-support/security-advisory/nport-iaw5000a-io-serial-device-server-vulnerabilities Vendor Advisory

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