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Advisory (ICSA-13-091-01)

Wind River VxWorks SSH and Web Server Multiple Vulnerabilities

Original release date: April 01, 2013 | Last revised: January 08, 2014

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Overview

This advisory provides mitigation details for multiple vulnerabilities in the Wind River VxWorks Remote Terminal Operating System (RTOS).

Hisashi Kojima and Masahiro Nakada of Fujitsu Laboratories have reported six vulnerabilities in Wind River’s VxWorks SSH and Web Server. Successful exploitation of these vulnerabilities could cause a denial-of-service (DoS) condition in the RTOS. One of these vulnerabilities could allow remote code execution if exploited. These vulnerabilities were originally reported to JPCERT/CC. Wind River has produced patches that mitigate these vulnerabilities. These vulnerabilities affect devices using VxWorks in the critical manufacturing, energy, and water and wastewater sectors.

These vulnerabilities can be exploited remotely.

Affected Products

The following Wind River products are affected:

  • Web Server & CLI vulnerabilities: VxWorks Versions 5.5 through 6.9, and
  • SSH vulnerabilities: VxWorks Versions 6.5 through 6.9.

Impact

Exploitation of each of these vulnerabilities can cause VxWorks to be unavailable until the next reboot.

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

Wind River is a US-based company that sells products around the world. Wind River is a wholly owned subsidiary of Intel Corporation.

The affected product, VxWorks, is a real time operating system. VxWorks and other RTOS are used within industrial control systems made by many different manufactures. Wind River VxWorks is deployed across several sectors including critical manufacturing, energy, water and wastewater, and others. Wind River estimates that these products are used worldwide.

Vulnerability Characterization

Vulnerability Overview

Improper Input Validationa

The SSH server (IPSSH) implementation in VxWorks 6.5 through 6.9 contains a DoS vulnerability due to an issue in processing authentication requests.b An attacker could send specially crafted authentication requests that cause SSH server outage. SSH access may become unavailable until the next reboot as a result of this vulnerability being exploited.

CVE-2013-0711 has been assigned to this vulnerability. A CVSS v2 base score of 7.8 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:N/I:N/A:C).

Improper Input Validationc

The SSH server (IPSSH) implementation in VxWorks 6.5 through 6.9 contains a DoS vulnerability due to an issue in processing pty requests.d Receiving a specially crafted pty request packet may cause SSH access to be unavailable until the next reboot. The attacker must login with a valid user name and password combination before launching a successful attack.

CVE-2013-0713 has been assigned to this vulnerability. A CVSS v2 base score of 6.8 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:S/C:N/I:N/A:C).

Improper Input Validatione

The SSH server (IPSSH) implementation in VxWorks 6.5 through 6.9 contains vulnerability due to an issue in the processing authentication requests.f  Receiving a specially crafted packet for a public key authentication request may cause the server to hang and SSH access to be unavailable until the next reboot. In addition, arbitrary code may be executed on the server with administrator privileges.

CVE-2013-0714 has been assigned to this vulnerability. A CVSS v2 base score of 8.5 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:N/I:P/A:C).

Command Injectiong

The WebCLI component in VxWorks 5.5 through 6.9 contains a DoS vulnerability due to an issue in parsing command strings.h An attacker that can login to a CLI session may cause the current CLI session to terminate. A new CLI session may be re-established without rebooting.

CVE-2013-0715 has been assigned to this vulnerability. A CVSS v2 base score of 6.8 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:S/C:N/I:N/A:C).

Improper Input Validationi

The Web Server in VxWorks 5.5 through 6.9 contains a DoS vulnerability.j  When a user accesses the VxWorks Web Server using a specially crafted URL, the server may crash.


CVE-2013-0716 has been assigned to this vulnerability. A CVSS v2 base score of 5.0 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:N/I:N/A:P).

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

According to Wind River, software patches for these vulnerabilities are available for all affected VxWorks versions. Users interested in obtaining these patches should contact Wind River technical support for assistance.

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. Critical devices 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.

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.

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 ICS-CERT at:

Email: ics-cert@hq.dhs.gov
Toll Free: 1-877-776-7585
International Callers: (208) 526-0900

For industrial control systems security information and incident reporting: http://ics-cert.us-cert.gov

ICS-CERT continuously strives to improve its products and services. You can help by choosing one of the links below to provide feedback about this product.

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