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TLP:WHITE

Advisory (ICSA-13-149-01)

Siemens SCALANCE Privilege Escalation Vulnerabilities

Original release date: May 29, 2013 | Last revised: December 13, 2013

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OVERVIEW

Siemens ProductCERTa has identified two privilege escalation vulnerabilities in Siemens SCALANCE X200 IRT switch devices. Siemens has produced a firmware upgradeb that mitigates these vulnerabilities. These vulnerabilities could be exploited remotely.

AFFECTED PRODUCTS

Siemens reports that the vulnerabilities affect the following versions of SCALANCE:

  • SCALANCE X204IRT versions < V5.1.0
  • SCALANCE X204IRT PRO versions < V5.1.0
  • SCALANCE X202-2IRT versions < V5.1.0
  • SCALANCE X202-2P IRT versions < V5.1.0
  • SCALANCE X202-2P IRT PRO versions < V5.1.0
  • SCALANCE X201-3P IRT versions < V5.1.0
  • SCALANCE X201-3P IRT PRO versions < V5.1.0
  • SCALANCE X200-4P IRT versions < V5.1.0
  • SCALANCE XF204IRT versions < V5.1.0

IMPACT

Successful exploitation of these vulnerabilities could allow an attacker to escalate his privileges within the Web interface. Users with administrator privileges can change configuration of the switches.

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

SCALANCE X Industrial Ethernet switches are industrial-grade Ethernet switches used to connect networked industrial components. This product line provides a Web interface to manage the switch configuration. SCALANCE X is used in the agriculture and food, critical manufacturing, government facilities, dams, transportation systems, water, chemical, defense industrial base, energy, and communications sectors.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

PRIVILEGE ESCALATIONc

The user privileges for the Web interface are enforced on the client side and not properly verified on the server side. Therefore, an attacker is able to execute privileged commands using an unprivileged account.

CVE-2013-3633d has been assigned to this vulnerability. Siemens calculated a CVSS v2 base score of 8.0; the CVSS vector string is (AV:N/AC:L/Au:S/C:P/I:P/A:C).e

PRIVILEGE ESCALATION

The implementation of SNMPv3 does not check the user credentials sufficiently. Therefore, an attacker is able to execute SNMP commands via Port 161/UDP without correct credentials.

CVE-2013-3634f has been assigned to this vulnerability. Siemens calculated a CVSS v2 base score of 7.5; the CVSS vector string is (AV:N/AC:L/Au:N/C:P/I:P/A:P).g

VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target these vulnerabilities.

DIFFICULTY

An attacker with a low skill would be able to exploit these vulnerabilities.

MITIGATION

Siemens provides firmware update SCALANCE X-200IRT V5.1.0,h which fixes both vulnerabilities. If it is not possible to install the firmware update, mitigate the SNMP vulnerability by either disabling SNMP or completely disabling read-write access.

ICS‑CERT encourages asset owners to take additional defensive measures to protect against this and other cybersecurity risks.

  • Minimize network exposure for all control system devices and/or systems. Critical devices and/or systems should not directly face the Internet.
  • Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
  • When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPN is only as secure as the connected devices.

ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT Web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. ICS‑CERT reminds organizations to perform proper impact analysis and risk assessment prior to taking defensive measures.

Additional mitigation guidance and recommended practices are publicly available in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B—Targeted Cyber Intrusion Detection and Mitigation Strategies, which is available for download from the ICS-CERT Web site (http://ics-cert.us-cert.gov/).

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS‑CERT for tracking and correlation against other incidents.


Contact Information

For any questions related to this report, please contact the NCCIC at:

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  http://ics-cert.us-cert.gov 
or incident reporting:  https://ics-cert.us-cert.gov/Report-Incident?

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