ICS-CERT: Siemens Scalence S Multiple Vulnerabilities

Thursday, April 12, 2012

Infosec Island Admin

7fef78c47060974e0b8392e305f0daf0

ICS-CERT has received a report from Siemens regarding two security vulnerabilities in the Scalance S Security Module firewall. This vulnerability was reported to Siemens by Adam Hahn and Manimaran Govindarasu for coordinated disclosure.

The first issue is a brute-force credential guessing vulnerability in the web configuration interface of the firewall. The second issue is a stack-based buffer overflow vulnerability in the Profinet DCP protocol stack.

Siemens has published a patch that resolves both of the identified vulnerabilities.

The following Scalance S Security Modules are affected:

• Scalance S602 V2
• Scalance S612 V2
• Scalance S613 V2

IMPACT

Successful exploitation of the brute-force vulnerability may allow an attacker to perform an arbitrary number of authentication attempts using different password and eventually gain access to the targeted account.

Successful exploitation of the stack-based buffer overflow against the Profinet DCP protocol may lead to a denial of service (DoS) condition or possible arbitrary code execution.

Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of these vulnerabilities based on their operational environment, architecture, and product implementation.

BACKGROUND

The Scalance S product is a security module that includes a Stateful Inspection Firewall for industrial automation network applications. This security module is intended to protect automation devices and industrial networks against unauthorized access and to secure Ethernet-based industrial communication.

This Siemens product is intended to protect trusted industrial networks from outside facing or untrusted networks. All Scalance S Security Modules provide filtering of incoming and outgoing network connections with stateful packet inspection.

This product is used predominately in Europe and Asia with a small US footprint. The primary sectors deploying Scalance S are Automotive, Defense Industrial Base, Energy, Critical Manufacturing, Transportation Systems, Chemical, and Water.

BRUTE-FORCE VULNERABILITY: The web server in the Scalance S Security Module does not implement sufficient measures to prevent rapid multiple authentication attempts within a short timeframe, making it susceptible to brute-force attacks by attackers with access to the web server. If the administrative password is found, the attacker can manipulate the configuration and gain access to the trusted network. CVE-2012-1799 been assigned to this vulnerability. A CVSS V2 base score of 10.0 has also been assigned.

STACK-BASED OVERFLOW: The Scalance S DCP protocol stack crashes when a specially crafted DCP frame is received, which may renders the firewall unresponsive and interrupts established VPN tunnels. Successful exploitation of this vulnerability may lead to a denial of service (DoS) condition or possible arbitrary code execution. CVE-2012-1800 been assigned to this vulnerability. Siemens has assigned a CVSS V2 base score of 6.1.

EXPLOITABILITY: These vulnerabilities are remotely exploitable.

EXISTENCE OF EXPLOIT: No known exploits specifically target these vulnerabilities.

DIFFICULTY: An attacker with a moderate skill level would be able to exploit these vulnerabilities.

MITIGATION

Siemens has published a patch that resolves both of the identified vulnerabilities and strongly recommends installing the updates by using the following links:

• The Siemens Security Advisory is available at: http://www.siemens.com/corporate-technology/pool/de/forschungsfelder/siemens_security_advisory_ssa-268149.pdf

• The firmware update is published on the following web site: http://support.automation.siemens.com/WW/view/en/59869684

• Information about industrial security by Siemens: http://www.siemens.com/industrialsecurity

• Recommended security practices by US-CERT: http://www.us-cert.gov/control_systems/practices/Recommended_Practices.html

• For further inquiries on vulnerabilities in Siemens products and solutions, please contact the Siemens ProductCERT: http://www.siemens.com/cert

The full ICS-CERT advisory can be found here:

Source:  http://www.us-cert.gov/control_systems/pdf/ICSA-12-102-05.pdf

Possibly Related Articles:
14195
SCADA
Industrial Control Systems
SCADA Vulnerabilities Siemens Buffer Overflow Brute Force Advisory ICS-CERT Industrial Control Systems Scalence S Stack Overflow
Post Rating I Like this!
The views expressed in this post are the opinions of the Infosec Island member that posted this content. Infosec Island is not responsible for the content or messaging of this post.

Unauthorized reproduction of this article (in part or in whole) is prohibited without the express written permission of Infosec Island and the Infosec Island member that posted this content--this includes using our RSS feed for any purpose other than personal use.