Rockwell Mitigation Plan for Ethernet Switch

Wednesday, April 18, 2018 @ 01:04 PM gHale

Rockwell Automation released a mitigation plan to handle multiple vulnerabilities in its Allen-Bradley Stratix Industrial Managed Ethernet Switch, according to a report with ICS-CERT.

The vulnerabilities include an improper input validation, resource management errors, 7PK – errors, improper restriction of operations within the bounds of a memory buffer, and use of externally-controlled format string.

RELATED STORIES
Moxa Clears Router Holes
Yokogawa’s Mitigations for CENTUM, Exaopc Hole
Omron Releases Update for CX-One
Mitigation Strategy for Rockwell’s MicroLogix

Successful exploitation of these remotely exploitable vulnerabilities could result in loss of availability, confidentiality, and/or integrity caused by memory exhaustion, module restart, information corruption, and/or information exposure.

Rockwell reported these vulnerabilities from the semi-annual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.

Allen-Bradley Stratix 8300 Industrial Managed Ethernet Switches, versions 15.2(4a) EA5 and earlier use a vulnerable version of Cisco IOS or IOS XE.

A vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition, or to execute arbitrary code on an affected device.

The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted Smart Install message to an affected device on TCP port 4786. A successful exploit could allow the attacker to cause a buffer overflow on the affected device.

CVE-2018-0171 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 9.8.

In addition, a vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated remote attacker to trigger a reload of an affected device, resulting in a DoS condition.

The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted packet to an affected device on TCP port 4786.

CVE-2018-0156 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.6.

Also, a vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation could allow an unauthenticated remote attacker to cause a crash of the iosd process, causing a DoS condition.

The vulnerability is due to insufficient error handling when the BFD header in a BFD packet is incomplete. An attacker could exploit this vulnerability by sending a crafted BFD message to or across an affected switch. A successful exploit could allow the attacker to trigger a reload of the system.

CVE-2018-0155 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.6.

Also, a vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated remote attacker to cause an affected device to reload, resulting in a DoS condition.

The vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

CVE-2018-0174 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.6.

In addition, a vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated remote attacker to cause an affected device to reload, resulting in a DoS condition.

The vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause a heap overflow condition on the affected device, which will cause the device to reload and result in a DoS condition.

CVE-2018-0172 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.6.

Also, a vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated remote attacker to cause an affected device to reload, resulting in a DoS condition.

The vulnerability exists because the affected software performs incomplete input validation of encapsulated option 82 information that it receives in DHCPOFFER messages from DHCPv4 servers. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device, which the device would then forward to a DHCPv4 server. When the affected software processes the option 82 information that is encapsulated in the response from the server, an error could occur. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

CVE-2018-0173 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.6.

Also, a buffer overflow vulnerability in the LLDP subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an adjacent, unauthenticated attacker to cause a DoS condition or execute arbitrary code with elevated privileges.

CVE-2018-0167 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.8.

In addition, a format string vulnerability in the LLDP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an adjacent, unauthenticated attacker to cause a DoS condition or execute arbitrary code with elevated privileges.

CVE-2018-0175 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 8.8.

The product mainly sees use in the critical manufacturing, energy, and water and wastewater systems. It also sees action on a global basis.

An attacker with low skill level could leverage the vulnerabilities.

In terms of mitigations, Rockwell released the following knowledge base article 1073315. (login required)

Cisco released new Snort Rules at https://www.cisco.com/web/software/286271056/117258/sf-rules-2018-03-29-new.html to help address the following vulnerabilities:
• CVE-2018-0171 – Snort Rule 46096 and 46097
• CVE-2018-0156 – Snort Rule 41725
• CVE-2018-0174 – Snort Rule 46120
• CVE-2018-0172 – Snort Rule 46104
• CVE-2018-0173 – Snort Rule 46119

Cisco added the following notes for the Smart Install vulnerabilities (CVE-2018-0171 and CVE-2018-0156):
• Smart Install is turned off by express setup; however, upgraded switches but not re-setup may have it enabled
• Disable the Smart Install feature with the no vstack configuration command if it is not needed or once setup is complete
• Users who do use the feature—and need to leave it enabled—can use ACLs to block incoming traffic on TCP port 4786

In terms of CVE-2018-0155: Administrators who do not use the BFD feature in their environments can disable the BFD feature by using the feature bfd disable command in global configuration mode to prevent exploitation of this vulnerability. Administrators who do use the BFD feature can implement Control Plane Policing (CoPP) to allow processing of BFD packets from known BFD peers only and drop all other BFD traffic to limit exposure.

CVE-2018-0167 and CVE-2018-0175 have no specific mitigations in place. See the following Cisco advisory for more details.

Rockwell also recommends users implement the following general security guidelines:
• Help minimize network exposure for all control system devices and/or systems, and confirm that they are not accessible from the Internet
• Locate control system networks and 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 VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices



Leave a Reply

You must be logged in to post a comment.