Synopsis
The remote OT asset is affected by a vulnerability.
Description
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 denial of service (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.
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Solution
The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at CISA.gov.
Rockwell Automation recommends users upgrade to FRN 15.2(6)E1 or later. Updated software can be downloaded at:
http://compatibility.rockwellautomation.com/Pages/MultiProductDownload.aspx?famID=15
Rockwell Automation has provided knowledge base article number 1073268 on their website at the following location to address these vulnerabilities:
https://rockwellautomation.custhelp.com/app/answers/detail/a_id/1073268/ (login required)
Rockwell Automation also recommends implementing the following mitigations in addition to upgrading the software version:
Cisco has 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
- CVE-2018-0158 - Snort Rule 46110
Cisco adds 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.
CVE-2018-0167 and CVE-2018-0175 have no specific mitigations in place. See the following Cisco Vulnerability advisory for more details:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-lldp
Rockwell Automation 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.
Plugin Details
Supported Sensors: Tenable OT Security
Risk Information
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Temporal Vector: CVSS:3.0/E:F/RL:O/RC:C
Vulnerability Information
CPE: cpe:/h:rockwellautomation:allen-bradley_stratix_5700_industrial_managed_ethernet_switch, cpe:/h:rockwellautomation:allen-bradley_stratix_5400_industrial_managed_ethernet_switch, cpe:/h:rockwellautomation:allen-bradley_stratix_5410_industrial_managed_ethernet_switch, cpe:/h:rockwellautomation:allen-bradley_stratix_8300_industrial_managed_ethernet_switch, cpe:/h:rockwellautomation:allen-bradley_stratix_8000_industrial_managed_ethernet_switch
Required KB Items: Tenable.ot/Rockwell
Exploit Ease: Exploits are available
Patch Publication Date: 3/28/2018
Vulnerability Publication Date: 3/28/2018
CISA Known Exploited Vulnerability Due Dates: 3/17/2022