PT-2012-10: Buffer overflow in the DiagAgent web server in WinCC (SCADA)

Vulnerable software

WinCC
Version: 7.0 SP3 before Update 2 and earlier

Application link:
http://www.siemens.com/

Severity level

Severity level: Medium
Impact: Buffer overflow
Access Vector: Network exploitable 

CVSS v2:
Base Score: 4.3
Vector: (AV:N/AC:M/Au:N/C:N/I:N/A:P)

CVE: CVE-2012-2598

Software description

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.

Vulnerability description

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

Advisory status

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

Credits

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)

References

http://en.securitylab.ru/lab/PT-2012-10
http://www.siemens.com/corporate-technology/pool/de/forschungsfelder/siemens_security_advisory_ssa-223158.pdf

Reports on the vulnerabilities previously discovered by Positive Research:

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

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