Cisco Security Advisory
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CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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Multiple vulnerabilities in the Image Signature Verification feature of Cisco NX-OS Software could allow an authenticated, local attacker with administrator-level credentials to install a malicious software image on an affected device.
The vulnerabilities exist because software digital signatures are not properly verified during CLI command execution. An attacker could exploit these vulnerabilities to install an unsigned software image on an affected device.
Note: If the device has not been patched for the vulnerability previously disclosed in the Cisco Security Advisory cisco-sa-20190306-nxos-sig-verif, a successful exploit could allow the attacker to boot a malicious software image.
Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-nxos-sisv2
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Vulnerable Products
These vulnerabilities affect the following Cisco products if they are running a vulnerable release of Cisco NX-OS Software:
- Nexus 3000 Series Switches
- Nexus 3600 Platform Switches
- Nexus 9000 Series Switches in standalone NX-OS mode
- Nexus 9500 R-Series Switching Platform
Note: For the Nexus 3000 Series Switches, only a subset of products supports image signature verification. The following Nexus 3000 Series product IDs (PIDs) are affected by these vulnerabilities:
- N3K-C31108PC-V
- N3K-C31108TC-V
- N3K-C31128PQ-10GE
- N3K-C3132C-Z
- N3K-C3164Q-40GE
- N3K-C3232C
- N3K-C3264C-E
- N3K-C3264Q
- N3K-C34180YC
- N3K-C3432D-I
- N3K-C3464C
For information about which Cisco NX-OS Software releases are vulnerable, see the Fixed Software section of this advisory.
Determining the Cisco NX-OS Product ID
To check the PID, administrators can use the show inventory command in the device CLI. The following example shows the output of the command for a device that has the PID N3K-C3232C:
switch# show inventory
NAME: "Chassis", DESCR: "Nexus3000 C3232C Chassis"
PID: N3K-C3232C , VID: V02 , SN: FOC20291JA0
NAME: "Slot 1", DESCR: "32x40/100G QSFP28 2x10G SFP+ Ethernet Module"
PID: N3K-C3232C , VID: V02 , SN: FOC20291JA0
NAME: "Power Supply 1", DESCR: "Nexus3000 C3232C Chassis Power Supply"
PID: NXA-PAC-650W-PI , VID: V01 , SN: LIT20362Z6GProducts Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.
Cisco has confirmed that these vulnerabilities do not affect the following Cisco products:
- Firepower 2100 Series
- Firepower 4100 Series
- Firepower 9300 Security Appliances
- MDS 9000 Series Multilayer Switches
- Nexus 1000V Switch for Microsoft Hyper-V
- Nexus 1000V Switch for VMware vSphere
- Nexus 3500 Platform Switches
- Nexus 5500 Platform Switches
- Nexus 5600 Platform Switches
- Nexus 6000 Series Switches
- Nexus 7000 Series Switches
- Nexus 7700 Series Switches
- Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode
- UCS 6200 Series Fabric Interconnects
- UCS 6300 Series Fabric Interconnects
- UCS 6400 Series Fabric Interconnects
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There are no workarounds that address these vulnerabilities.
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Cisco has released free software updates that address the vulnerabilities described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license: https://www.cisco.com/c/en/us/products/end-user-license-agreement.html
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
Customers are advised to upgrade to an appropriate release as indicated in the applicable table in this section. In the following tables, the left column lists Cisco NX-OS Software releases. The right column indicates the first release that includes the fix for these vulnerabilities.Note: A complete fix for these vulnerabilities requires that a proper BIOS version is installed. Customers who are running an affected product that is listed in the previously disclosed Cisco advisory cisco-sa-20190306-nxos-sig-verif may not have upgraded the BIOS when the software was installed even if they are running a fixed software release. Customers are advised to confirm that the BIOS is running a fixed BIOS version (first fixed or later) as described in the previously disclosed advisory.
Nexus 3000 Series Switches: CSCvj14182, CSCvj14106, CSCvj14093
Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities Prior to 6.0(2) Not vulnerable 6.0(2) Not vulnerable Prior to 7.0(3)I4 7.0(3)I7(5) 7.0(3)I4 7.0(3)I7(5) 7.0(3)I5 7.0(3)I7(5) 7.0(3)I6 7.0(3)I7(5) 7.0(3)I7 7.0(3)I7(5) 9.2 9.2(2)
Nexus 3600 Platform Switches and Nexus 9500 R-Series Switching Platform: CSCvk53256, CSCvk53227, CSCvk53125
Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities 7.0(3)F3 7.0(3)F3(5) 9.2 9.2(2)
Nexus 9000 Series Switches in Standalone NX-OS Mode: CSCvj14182, CSCvj14106, CSCvj14093
Cisco NX-OS Software Release First Fixed Release for These Vulnerabilities Prior to 7.0(3)I4 7.0(3)I7(5) 7.0(3)I4 7.0(3)I7(5) 7.0(3)I5 7.0(3)I7(5) 7.0(3)I6 7.0(3)I7(5) 7.0(3)I7 7.0(3)I7(5) 9.2 9.2(2) Additional Resources
For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, administrators can refer to the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.
For help determining the best Cisco NX-OS Software release for Cisco UCS, refer to the Recommended Releases documents in the release notes for the device.Cisco MDS Series Switches
Cisco Nexus 1000V for VMware Switch
Cisco Nexus 3000 Series and 3500 Series Switches
Cisco Nexus 5000 Series Switches
Cisco Nexus 5500 Platform Switches
Cisco Nexus 6000 Series Switches
Cisco Nexus 7000 Series Switches
Cisco Nexus 9000 Series Switches
Cisco Nexus 9000 Series ACI-Mode Switches
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
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These vulnerabilities were found during internal security testing.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.0 Initial public release. — Final 2019-May-15
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