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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-nxos-sisv2
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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-nxos-sisv2
These vulnerabilities affect the following Cisco products if they are running a vulnerable release of Cisco NX-OS Software:
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:
For information about which Cisco NX-OS Software releases are vulnerable, see the Fixed Software section of this advisory.
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:
Vulmon
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: LIT20362Z6G
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:There are no workarounds that address these vulnerabilities.
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 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.
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) |
| 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) |
| 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) |
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
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.
These vulnerabilities were found during internal security testing.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2019-May-15 |
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