PT-2012-50: Multiple vulnerabilities in Siemens SIMATIC S7-1200 Web interface

Vulnerable product

Siemens SIMATIC S7-1200
Version: 2.x, 3.0.0, 3.0.1

Severity level

Severity level: High
Impact: Cross-Site Scripting
Access Vector: Remote

CVSS v2:
Base Score: 8.3
Vector: (AV:N/AC:M/Au:N/C:P/I:P/A:C)

CVE: not assigned

Product description

SIMATIC S7-1200 controllers are new modular miniature controllers. Due to the compact modular design with a high performance at the same time, the SIMATIC S7-1200 is suitable for a wide variety of automation applications. Its range of use extends from the replacement of relays and contactors up to complex automation tasks in networks and within distributed structures.

Vulnerability description

The specialists of the Positive Research center have detected multiple vulnerabilities in Siemens SIMATIC S7-1200.

If a user is enticed to activate a malicious URL directed at the S7-1200 web server IP address, the Cross-Site Scripting vulnerability could be exploited. If the attack is successful, the attacker could manipulate what the browser displays when viewing the S7-1200’s web pages, steal session cookies, or redirect the user’s browser to a malicious web site. In addition, it may be possible for attackers to issue commands to the S7-1200 web server at the user’s privilege level.

How to fix

Siemens provides a firmware update for versions 3.0.0 and 3.0.1 of the SIMATIC S7-1200 PLC, which should be applied as soon as possible in cases where the embedded web server is utilized as it fixes the XSS vulnerability. Additionally, a HTTP PUT command is supported by the web server which does not impact security. As it is unnecessary for normal use of the S7-1200 web server, it will be removed starting with version 3.0.2.

Workaround

Advisory status

08.08.2012 - Vendor is notified
08.08.2012 - Vendor gets vulnerability details
08.10.2012 - Vendor releases fixed version and details
11.10.2012 - Public disclosure

Credits

The vulnerabilities was discovered by Dmitry Serebryannikov, Artem Chaikin, Yury Goltsev, Timur Yunusov, Positive Research Center (Positive Technologies Company)

References

http://en.securitylab.ru/lab/PT-2012-50
http://www.siemens.com/corporate-technology/pool/de/forschungsfelder/siemens_security_advisory_ssa-279823.pdf

Reports on the vulnerabilities previously discovered by Positive Research:

http://ptsecurity.com/research/advisory/
http://en.securitylab.ru/lab/