Vulnerability for D-Link Router
Product: D-Link DIR-823G (Refer: http://www.dlink.com.cn/home/product?id=2960)
Version: The latest firmware -- 1.02B03 (Download link: http://support.dlink.com.cn/ProductInfo.aspx?m=DIR-823G)
Vulnerability Type: Incorrect Access Control
Author: David Chen
Institution: Technology Research Institute of Legendsec at Qi’anxin Group
An issue was discovered in /bin/goahead on D-Link DIR-823G with latest firmware 1.02B03. There is a incorrect access control problem allowing remote attackers to hijack DNS of all clients in WLAN without authentication via access a HNAP API named SetWanSettings.
Attacker should call a HNAP API SetWanSettings remotely and set DNS server of router immediately. Attacker just need to send a POST request as below:
Headers:
Body:
This PoC can result in a change of DNS server as below, you can see that the DNS server is set to "192.168.3.1" after exploit:
Before exploit:
After exploit:
P.S. Given the vendor's security, we only provide parts of this exploit.