PT-2012-10: Buffer overflow in the DiagAgent web server in WinCC (SCADA)
Version: 7.0 SP3 before Update 2 and earlier
Severity level: Medium
Impact: Buffer overflow
Access Vector: Network exploitable
Base Score: 4.3
Simatic WinCC is a part of Siemens SIMATIC HMI software that aimed to provide connection between an operator and PLCs that manage technological processes. SIMATIC HMI is responsible for technical process visualization, alarm system, process assessment and error logging, and also manages device parameters. The software is used in a number of industries including food, oil, gas, chemical, power industries.
The specialists of the Positive Research center have a vulnerability detected "Buffer overflow" in the DiagAgent web server in WinCC.
The DiagAgent web server is used for remote diagnostic purposes and is turned off by default. If it is turned on, it does not sanitize user input correctly. Specially crafted input can crash the DiagAgent, rendering remote diagnostic unusable.
How to fix
Update your software up to the latest version
23.05.2012 - Vendor is notified
23.05.2012 - Vendor gets vulnerability details
05.06.2012 - Vendor releases fixed version and details
20.06.2012 - Public disclosure
The vulnerability was discovered by Sergey Scherbel, Yury Goltsev, Dmitry Serebryannikov, Sergey Bobrov, Denis Baranov, Andrey Medov, Artem Chaykin, Positive Research Center (Positive Technologies Company)
Reports on the vulnerabilities previously discovered by Positive Research: