Siglent Technologies SDS 1202X-E Digital Oscilloscope 5.1.3.13 Hardcoded Credentials

2018.12.03
Credit: T. Weber
Risk: Medium
Local: No
Remote: Yes
CVE: N/A
CWE: N/A

SEC Consult Vulnerability Lab Security Advisory < 20181130-0 > ======================================================================= title: Multiple Vulnerabilities product: Siglent Technologies SDS 1202X-E Digital Oscilloscope vulnerable version: V5.1.3.13 fixed version: - CVE number: - impact: High homepage: http://siglenteu.com/ https://www.siglent.eu/ https://www.siglentamerica.com/ found: 2018-08-06 by: T. Weber (Office Vienna) SEC Consult Vulnerability Lab An integrated part of SEC Consult Europe | Asia | North America https://www.sec-consult.com ======================================================================= Vendor description: ------------------- "SIGLENT is an international high-tech company, concentrating on R&D, sales, production and services of measurement products. As an ISO9001:2000 International Quality Management System and ISO 14001:2004 Environmental Management System Certified company, SIGLENT is also a member of the China Electronic Instrument Industry Association and Guangdong Instrument Representative Association. [...] SIGLENT focuses on the electronic test & measurement instrument industry and sees research & development as a core competency, while keeping a strong competitive edge through technology innovation and strict quality control. Try a Siglent product. Then compare the performance and the features to any other model, any other brand. Then compare the price. We believe there is no better value anyplace." Source: http://www.siglenteu.com/about.aspx Business recommendation: ------------------------ The identified backdoor accounts are accessible through Telnet, hence a compromise of the device via a local network attack is possible. Any malicious modification of measurement values may have serious impact on the product or service which is created or offered by using this oscilloscope. Therefore, all procedures which are executed with this device are untrustworthy. SEC Consult recommends not to use this product within a network of a production environment until a thorough security review has been performed by security professionals and all identified issues have been resolved. The vendor was unresponsive and did not provide a patch. Vulnerability overview/description: ----------------------------------- 1) Hardcoded Backdoor Accounts Two backdoor accounts are present on the system. A Telnet service is listening on port 23 which enables an attacker to connect as root to the oscilloscope via LAN. The password hashes are hardcoded and are difficult to change for the end user because the "shadow" file is stored on a cramfs (intentionally write-only) file system. 2) Missing Authentication / Design Issue The software "EasyScopeX" can be used from any computer in the network to configure and interact with the oscilloscope. This is possible without prior authentication which enables everyone to change settings on the oscilloscope. 3) Unencrypted Communication The software "EasyScopeX" communicates via unencrypted TCP packets with the client computer / oscilloscope. 4) Outdated and Vulnerable Software Components Multiple software components embedded in the firmware are outdated and found to be vulnerable to various publicly known security issues. Proof of concept: ----------------- 1) Hardcoded Backdoor Accounts The following password hashes were dumped from "/etc/shadow" by connecting to the UART interface on the PCB: root siglent (The password hashes have been removed from this advisory) 2) Missing Authentication / Design Issue It is sufficient to install the "EasyScopeX" software and control the oscilloscope without any authentication. 3) Unencrypted Communication The software "EasyScopeX" communicates in plaintext via various ports by using the portmapper. The default ports are "5024" and "5025". 4) Outdated and Vulnerable Software Components Using the IoT Inspector software we found the following outdated and vulnerable components: * BusyBox 1.20.1 * GNU glibc 2.13 * Linux Kernel 3.19.0 Vulnerable / tested versions: ----------------------------- The following device / firmware version has been tested: * Siglent SDS1202X-E (V5.1.3.13) It is assumed that other firmware versions are affected as well. Vendor contact timeline: ------------------------ 2018-08-22: Contacting German VDE CERT for coordination support 2018-09-04: Asking for a status update from the vendor 2018-09-05: VDE CERT: no response from vendor yet 2018-09-12: US sales person from Siglent has answered, VDE CERT is sending advisory to be forwarded to engineering 2018-10-10: Asking for a status update (affected versions, etc) 2018-10-10: VDE CERT: asking vendor for update, vendor reply: "I forwarded it to our VP of Engineering for consideration. The R&D offices are located in China, so I do not have any further visibility or information." 2018-10-12: VDE CERT: if there are no news until end of October, we will release security advisory beginning of November 2018-11-23: VDE CERT: no news from the vendor, planning release 2018-11-30: Public release of security advisory Solution: --------- The vendor was unresponsive and did not provide a patch. See workaround section to reduce the attack surface. Workaround: ----------- * Don't use the LAN interface or if needed use only in trusted networks * Connect to the UART interface and place a script which closes port 23 on the device during bootup if Telnet is not used. 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 / @2018


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