Device info

• Device model: DIR-600M C1
• Firmware version: 3.08
• Download link: https://dlink.co.in/firmware/ftp.aspx

Description and impact

Dlink DIR-600M C1 has buffer overflow in authentication that allows unauthenticated attacker to performce Denial of Service attack. Attacker can send payload to web login or telnet login (which is disabled by default). This vulnerability is as same as CVE-2021-26709 which possibly leads to unauthenticated remote code execution.

Steps to reprocedure

1. Vulnerable device (IP Address: 192.168.100.1) must enable Telnet protocol.

2. Attacker sent a crafted payload which contains a very long username

3. Device crashed. All open ports were down. Clients lost internet connection. Device rebooted automatically after a few minutes.

References

• https://www.cvedetails.com/cve/CVE-2021-26709/