SEC Consult Vulnerability Lab Security Advisory < 20190612-0 > ======================================================================= title: Multiple vulnerabilities product: WAGO 852 Industrial Managed Switch Series vulnerable version: 852-303: <v1.2.2.S0 852-1305: <v1.1.6.S0 852-1505: <v1.1.5.S0 fixed version: 852-303: v1.2.2.S0 852-1305: v1.1.6.S0 852-1505: v1.1.5.S0 CVE number: CVE-2019-12550, CVE-2019-12549 impact: high homepage: https://www.wago.com found: 2019-03-08 by: T. Weber (Office Vienna) IoT Inspector SEC Consult Vulnerability Lab An integrated part of SEC Consult Europe | Asia | North America https://www.sec-consult.com ======================================================================= Vendor description: ------------------- "New ideas are the driving force behind our success WAGO is a family-owned company headquartered in Minden, Germany. Independently operating for three generations, WAGO is the global leader of spring pressure electrical interconnect and automation solutions. For more than 60 years, WAGO has developed and produced innovative products for packaging, transportation, process, industrial and building automation markets amongst others. Aside from its innovations in spring pressure connection technology, WAGO has introduced numerous innovations that have revolutionized industry. Further ground-breaking inventions include: the WAGO-I/O-SYSTEM®, TOPJOB S® and WALL-NUTS®." Source: http://www.wago.us/wago/ Business recommendation: ------------------------ SEC Consult recommends to immediately apply the available patches from the vendor. A thorough security review should be performed by security professionals to identify further potential security issues. Vulnerability overview/description: ----------------------------------- The industrial managed switch series 852 from WAGO is affected by multiple vulnerabilities such as old software components embedded in the firmware. Furthermore, hardcoded password hashes and credentials were also found by doing an automated scan with IoT Inspector. Two vulnerabilities (CVE-2017-16544 and CVE-2015-0235) were verified by emulating the device with the MEDUSA scaleable firmware runtime. The validity of the password hashes and the embedded keys were also verified by emulating the device. 1) Known BusyBox Vulnerabilities The used BusyBox toolkit in version 1.12.0 is outdated and contains multiple known vulnerabilities. The outdated version was found by IoT Inspector. One of the discovered vulnerabilities (CVE-2017-16544) was verified by using the MEDUSA scaleable firmware runtime. 2) Known GNU glibc Vulnerabilities The used GNU glibc in version 2.8 is outdated and contains multiple known vulnerabilities. The outdated version was found by IoT Inspector. One of the discovered vulnerabilities (CVE-2015-0235, "GHOST") was verified by using the MEDUSA scaleable firmware runtime. 3) Hardcoded Credentials (CVE-2019-12550) The device contains hardcoded users and passwords which can be used to login via SSH and Telnet. 4) Embedded Private Keys (CVE-2019-12549) The device contains hardcoded private keys for the SSH daemon. The fingerprint of the SSH host key from the corresponding SSH daemon matches to the embedded private key. Proof of concept: ----------------- 1) Known BusyBox Vulnerabilities BusyBox version 1.12.0 contains multiple CVEs like: CVE-2013-1813, CVE-2016-2148, CVE-2016-6301, CVE-2011-2716, CVE-2011-5325, CVE-2015-9261, CVE-2016-2147 and more. The BusyBox shell autocompletion vulnerability (CVE-2017-16544) was verified on an emulated device. A file with the name "\ectest\n\e]55;test.txt\a" was created to trigger the vulnerability. ------------------------------------------------------------------------------- # ls "pressing <TAB>" test ]55;test.txt # ------------------------------------------------------------------------------- 2) Known GNU glibc Vulnerabilities GNU glibc version 2.8 contains multiple CVEs like: CVE-2010-0296, CVE-2010-3856, CVE-2012-4412, CVE-2014-4043, CVE-2014-9402, CVE-2014-9761, CVE-2014-9984, CVE-2015-1472 and more. The gethostbyname buffer overflow vulnerability (GHOST) was checked with the help of the exploit code from https://seclists.org/oss-sec/2015/q1/274. It was compiled and executed on the emulated device to test the system. 3) Hardcoded Credentials (CVE-2019-12550) The following credentials were found in the 'passwd' file of the firmware: <Password Hash> <Plaintext> <User> <removed> <removed> root No password is set for the account [EMPTY PASSWORD] admin By using these credentials, it's possible to connect via Telnet and SSH on the emulated device. Example for Telnet: ------------------------------------------------------------------------------- [root@localhost ~]# telnet 192.168.0.133 Trying 192.168.0.133... Connected to 192.168.0.133. Escape character is '^]'. L2SWITCH login: root Password: ~ # ------------------------------------------------------------------------------- Example for SSH: ------------------------------------------------------------------------------- [root@localhost ~]# ssh 192.168.0.133 root@192.168.0.133's password: ~ # ------------------------------------------------------------------------------- 4) Embedded Private Keys (CVE-2019-12549) The following host key fingerprint is shown by accessing the SSH daemon on the emulated device: [root@localhost ~]# ssh 192.168.0.133 The authenticity of host '192.168.0.133 (192.168.0.133)' can't be established. RSA key fingerprint is SHA256:X5Vr0/x0/j62N/aqZmHz96ojwl8x/I8mfzuT8o6uZso. RSA key fingerprint is MD5:2e:65:85:fc:45:04:bd:68:30:74:51:45:7d:2f:95:e2. This matches the embedded private key (which has been removed from this advisory): SSH Fingerprint: 2e:65:85:fc:45:04:bd:68:30:74:51:45:7d:2f:95:e2 Vulnerable / tested versions: ----------------------------- According to the vendor, the following versions are affected: * 852-303: <v1.2.2.S0 * 852-1305: <v1.1.6.S0 * 852-1505: <v1.1.5.S0 Vendor contact timeline: ------------------------ 2019-03-12: Contacting VDE CERT through info@cert.vde.com, received confirmation 2019-03-26: Asking for a status update, VDE CERT is still waiting for details 2019-03-28: VDE CERT requests information from WAGO again 2019-04-09: Asking for a status update 2019-04-11: VDE CERT: patched firmware release planned for end of May, requested postponement of advisory release 2019-04-16: VDE CERT: update regarding affected firmware versions 2019-04-24: Confirming advisory release for beginning of June 2019-05-20: Asking for a status update 2019-05-22: VDE CERT: no news from WAGO yet, 5th June release date 2019-05-29: Asking for a status update 2019-05-29: VDE CERT: detailed answer from WAGO, patches will be published on 7th June, SEC Consult proposes new advisory release date for 12th June 2019-06-07: VDE CERT provides security advisory information from WAGO; WAGO releases security patches 2019-06-12: Coordinated release of security advisory Solution: --------- The vendor provides patches to their customers at their download page. The following versions fix the issues: * 852-303: v1.2.2.S0 * 852-1305: v1.1.6.S0 * 852-1505: v1.1.5.S0 According to the vendor, busybox and glibc have been updated and the embedded private keys are being newly generated upon first boot and after a factory reset. The root login via Telnet and SSH has been disabled and the admin account is documented and can be changed by the customer. Workaround: ----------- Restrict network access to the device & SSH server. Advisory URL: ------------- https://www.sec-consult.com/en/vulnerability-lab/advisories/index.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Vulnerability Lab SEC Consult Europe | Asia | North America About SEC Consult Vulnerability Lab The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It ensures the continued knowledge gain of SEC Consult in the field of network and application security to stay ahead of the attacker. The SEC Consult Vulnerability Lab supports high-quality penetration testing and the evaluation of new offensive and defensive technologies for our customers. Hence our customers obtain the most current information about vulnerabilities and valid recommendation about the risk profile of new technologies. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interested to work with the experts of SEC Consult? Send us your application https://www.sec-consult.com/en/career/index.html Interested in improving your cyber security with the experts of SEC Consult? Contact our local offices https://www.sec-consult.com/en/contact/index.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mail: research at sec-consult dot com Web: https://www.sec-consult.com Blog: http://blog.sec-consult.com Twitter: https://twitter.com/sec_consult EOF T. Weber / @2019