Siemens SINEMA Remote Connect Server Cross-site Scripting Vulnerability
ICSA： ICS Advisory (ICSA-16-208-03)
Researchers Antonio Morales Maldonado of INNOTEC SYSTEM, and Alexander Van Maele and Tijl Deneut of Howest have identified a cross-site scripting (XSS) vulnerability in the Siemens SINEMA Remote Connect Server application. Siemens has produced an update to mitigate this vulnerability.
This vulnerability could be exploited remotely.
The following SINEMA Remote Connect Server versions are affected:
- SINEMA Remote Connect Server, all versions prior to Version 1.2
Exploiting this vulnerability could enable attackers to read some files from Siemens SINEMA Remote Connect Server devices. This could enable a remote attacker ongoing access to these devices.
Impact to individual organizations depends on many factors that are unique to each organization. NCCIC/ICS-CERT recommends that organizations evaluate the impact of this vulnerability based on their operational environment, architecture, and product implementation.
Siemens is a multinational company headquartered in Munich, Germany.
The affected product, SINEMA Remote Connect Server, is a network management appliance for industrial applications and allows network monitoring as well as diagnostics and reporting functions integrated into SCADA systems such as WinCC. According to Siemens, SINEMA products are deployed across several sectors including Chemical, Commercial Facilities, Critical Manufacturing, Energy, Government Facilities, Water and Wastewater Systems, and others. Siemens estimates that this product is used primarily in the United States and Europe with a small percentage in Asia.
The integrated web server (Port 443/TCP) of the affected SINEMA Remote Connect Server could allow XSS attacks if unsuspecting users are tricked into accessing a malicious link.
This vulnerability could be exploited remotely.
EXISTENCE OF EXPLOIT
No known public exploits specifically target this vulnerability.
An attacker with a low skill would be able to exploit this vulnerability. Social engineering is required to convince the user into accessing a malicious link. This decreases the likelihood of a successful exploit.
Siemens provides software update V1.2 for SINEMA Remote Connect Server which fixes the vulnerability and recommends users update to the new version. The software update for SINEMA Remote Connect Server can be obtained at:
As a general security measure, Siemens strongly recommends to configure the environment according to its operational guidelines available at:
For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-119132 at the following location:
ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
- Minimize network exposure for all control system devices and/or systems.
- Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
In addition, ICS-CERT recommends that users take the following measures to protect themselves from social engineering attacks:
- Do not click web links or open unsolicited attachments in email messages.
- Refer to Recognizing and Avoiding Email Scamsd for more information on avoiding email scams.
- Refer to Avoiding Social Engineering and Phishing Attackse for more information on social engineering attacks.
ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page at: http://ics-cert.us-cert.gov/content/recommended-practices. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
Additional mitigation guidance and recommended practices are publicly available in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site (http://ics-cert.us-cert.gov/).
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents.
- a. CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), http://cwe.mitre.org/data/definitions/79.html, web site last accessed July 26, 2016.
- b. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-6204, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory.
- c. CVSS Calculator https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N/E:P/RL:O/RC:C, web site last accessed July 26, 2016.
- d. Recognizing and Avoiding Email Scams, http://www.us-cert.gov/reading_room/emailscams_0905.pdf, web site last accessed July 26, 2016.
- e. National Cyber Alert System Cyber Security Tip ST04-014, http://www.us-cert.gov/cas/tips/ST04-014.html, web site last accessed July 26, 2016.