PT-2013-44: Forced browsing in Siemens WinCC and SIMATIC PCS 7

Vulnerable software

Siemens WinCC
Version: 7.2 and earlier

Siemens SIMATIC PCS 7
Version: 8.0 SP1 and earlier

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

Severity level

Severity level: Medium
Impact: Username Access
Access Vector: Remote

CVSS v2:
Base Score: 4.0
Vector: (AV:N/AC:L/Au:S/C:P/I:N/A:N)

CVE: CVE-2013-3959

Software description

Siemens WinCC is a part of Siemens SIMATIC HMI software that aimed to provide connection between an operator and PLCs that manage technological processes. The WebNavigator component of WinCC gives the users the possibility to control their plants via the web browser with the same look-and-feel like local operator stations.

Vulnerability description

The specialists of the Positive Research center have detected a vulnerability, which can be used to gain access to usernames in Siemens WinCC and SIMATIC PCS 7.

The WinCC Web Navigator 7.2 allows a user with authenticated access to probe for valid NetBIOS user names by manipulating URL parameters. This could allow the attacker to obtain user names with heightened privileges.

How to fix

Update your software up to the latest version

Advisory status

13.01.2013 - Vendor gets vulnerability details
14.06.2013 - Vendor releases fixed version and details
03.07.2013 - Public disclosure

Credits

The vulnerability was detected by Alexander Tlyapov, Positive Research Center (Positive Technologies Company)

References

<http://en.securitylab.ru/lab/PT-2013-44&gt;
<http://www.siemens.com/corporate-technology/pool/de/forschungsfelder/siemens_security_advisory_ssa-345843.pdf&gt;
<https://ics-cert.us-cert.gov/advisories/ICSA-13-169-02&gt;

Reports on the vulnerabilities previously discovered by Positive Research:

<http://ptsecurity.com/research/advisory/&gt;
<http://en.securitylab.ru/lab/&gt;