PT-2013-84: Insuffient Entropy in Siemens SIMATIC S7-1500 CPU PLC
Siemens SIMATIC S7-1500 CPU PLC
Version: 1.1.x and earlier
Severity level: High
Impact: Session Hijaking, Information Disclosure, Denial of Service
Access Vector: Remote
Base Score: 8.3
Siemens SIMATIC S7-1500 - controllers featuring high efficiency in data processing, integrated technological functions of Motion Control, PID control and the use of high-speed counters..
The specialists of the Positive Research center have detected an Insuffient Entropy vulnerability in Siemens SIMATIC S7-1500 CPU PLC.
Due to low entropy in its random number generator, the authentication of the integrated web server (port 80/tcp and port 443/tcp) of S7-1500 PLCs might allow attackers to hijack web sessions over the network without authentication.
How to fix
Update your firmware up to the latest version
05.08.2013 - Vendor gets vulnerability details
12.03.2014 - Vendor releases fixed version and details
25.03.2014 - Public disclosure
The vulnerability was detected by Alexey Osipov and Alexander Timorin, Positive Research Center (Positive Technologies Company)
Reports on the vulnerabilities previously discovered by Positive Research: