A vulnerability in the Image Signature Verification feature used in an NX-OS CLI command in Cisco Nexus 3000 Series and 9000 Series Switches could allow an authenticated, local attacker with administrator-level credentials to install a malicious software image on an affected device. The vulnerability exists because software digital signatures are not properly verified during CLI command execution. An attacker could exploit this vulnerability 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.

A vulnerability in the logic that handles access control to one of the hardware components in Cisco's proprietary Secure Boot implementation could allow an authenticated, local attacker to write a modified firmware image to the component. This vulnerability affects multiple Cisco products that support hardware-based Secure Boot functionality. The vulnerability is due to an improper check on the area of code that manages on-premise updates to a Field Programmable Gate Array (FPGA) part of the Secure Boot hardware implementation. An attacker with elevated privileges and access to the underlying operating system that is running on the affected device could exploit this vulnerability by writing a modified firmware image to the FPGA. A successful exploit could either cause the device to become unusable (and require a hardware replacement) or allow tampering with the Secure Boot verification process, which under some circumstances may allow the attacker to install and boot a malicious software image. An attacker will need to fulfill all the following conditions to attempt to exploit this vulnerability: Have privileged administrative access to the device. Be able to access the underlying operating system running on the device; this can be achieved either by using a supported, documented mechanism or by exploiting another vulnerability that would provide an attacker with such access. Develop or have access to a platform-specific exploit. An attacker attempting to exploit this vulnerability across multiple affected platforms would need to research each one of those platforms and then develop a platform-specific exploit. Although the research process could be reused across different platforms, an exploit developed for a given hardware platform is unlikely to work on a different hardware platform.

A vulnerability in the Fibre Channel over Ethernet (FCoE) N-port Virtualization (NPV) protocol implementation in Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. The vulnerability is due to an incorrect processing of FCoE packets when the fcoe-npv feature is uninstalled. An attacker could exploit this vulnerability by sending a stream of FCoE frames from an adjacent host to an affected device. An exploit could allow the attacker to cause packet amplification to occur, resulting in the saturation of interfaces and a DoS condition. Nexus 9000 Series Switches in Standalone NX-OS Mode are affected running software versions prior to 7.0(3)I7(5) and 9.2(2).

A vulnerability 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 vulnerability is due to improper verification of digital signatures for software images. An attacker could exploit this vulnerability by loading an unsigned software image on an affected device. A successful exploit could allow the attacker to boot a malicious software image. Note: The fix for this vulnerability requires a BIOS upgrade as part of the software upgrade. For additional information, see the Details section of this advisory. Nexus 3000 Series Switches are affected running software versions prior to 7.0(3)I7(5). Nexus 9000 Series Fabric Switches in ACI Mode are affected running software versions prior to 13.2(1l). Nexus 9000 Series Switches in Standalone NX-OS Mode are affected running software versions prior to 7.0(3)I7(5). Nexus 9500 R-Series Line Cards and Fabric Modules are affected running software versions prior to 7.0(3)F3(5).

A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system of an affected device. The vulnerability is due to insufficient validation of arguments passed to certain CLI commands. An attacker could exploit this vulnerability by including malicious input as the argument of an affected command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with elevated privileges. An attacker would need valid administrator credentials to exploit this vulnerability. MDS 9000 Series Multilayer Switches are affected running software versions prior to 6.2(27) and 8.2(3). Nexus 3000 Series Switches are affected running software versions prior to 7.0(3)I4(9) and 7.0(3)I7(6). Nexus 3500 Platform Switches are affected running software versions prior to 6.0(2)A8(11) and 7.0(3)I7(6). Nexus 3600 Platform Switches are affected running software versions prior to 7.0(3)F3(5). Nexus 9000 Series Switches in Standalone NX-OS Mode are affected running software versions prior to 7.0(3)I4(9), 7.0(3)I7(6). Nexus 9500 R-Series Line Cards and Fabric Modules are affected running software versions prior to 7.0(3)F3(5). Nexus 7000 and 7700 Series Switches are affected running software versions prior to 6.2(22) and 8.2(3).

A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. The vulnerability is due to an issue with allocating and freeing memory buffers in the network stack. An attacker could exploit this vulnerability by sending crafted TCP streams to an affected device in a sustained way. A successful exploit could cause the network stack of an affected device to run out of available buffers, impairing operations of control plane and management plane protocols, resulting in a DoS condition. Note: This vulnerability can be triggered only by traffic that is destined to an affected device and cannot be exploited using traffic that transits an affected device. Nexus 1000V Switch for Microsoft Hyper-V is affected in versions prior to 5.2(1)SM3(2.1). Nexus 1000V Switch for VMware vSphere is affected in versions prior to 5.2(1)SV3(4.1a). Nexus 3000 Series Switches are affected in versions prior to 7.0(3)I7(6) and 9.2(2). Nexus 3500 Platform Switches are affected in versions prior to 6.0(2)A8(11), 7.0(3)I7(6), and 9.2(2). Nexus 3600 Platform Switches are affected in versions prior to 7.0(3)F3(5) and 9.2(2). Nexus 5500, 5600, and 6000 Series Switches are affected in versions prior to 7.1(5)N1(1b) and 7.3(5)N1(1). Nexus 7000 and 7700 Series Switches are affected in versions prior to 6.2(22. Nexus 9500 R-Series Line Cards and Fabric Modules are affected in versions prior to 7.0(3)F3(5) and 9.2(2). UCS 6200 and 6300 Series Fabric Interconnect are affected in versions prior to 3.2(3j) and 4.0(2a). UCS 6400 Series Fabric Interconnect are affected in versions prior to 4.0(2a).

A vulnerability in the 802.1X implementation for Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to incomplete input validation of Extensible Authentication Protocol over LAN (EAPOL) frames. An attacker could exploit this vulnerability by sending a crafted EAPOL frame to an interface on the targeted device. A successful exploit could allow the attacker to cause the Layer 2 (L2) forwarding process to restart multiple times, leading to a system-level restart of the device and a DoS condition. Note: This vulnerability affects only NX-OS devices configured with 802.1X functionality. Cisco Nexus 1000V Switch for VMware vSphere devices are affected in versions prior to 5.2(1)SV3(1.4b). Nexus 3000 Series Switches are affected in versions prior to 7.0(3)I7(4). Nexus 3500 Platform Switches are affected in versions prior to 7.0(3)I7(4). Nexus 2000, 5500, 5600, and 6000 Series Switches are affected in versions prior to 7.3(5)N1(1) and 7.1(5)N1(1b). Nexus 7000 and 7700 Series Switches are affected in versions prior to 8.2(3). Nexus 9000 Series Fabric Switches in ACI Mode are affected in versions prior to 13.2(1l). Nexus 9000 Series Switches in Standalone NX-OS Mode are affected in versions prior to 7.0(3)I7(4).

A vulnerability in the Bash shell implementation for Cisco NX-OS Software could allow an authenticated, local attacker to escalate their privilege level by executing commands authorized to other user roles. The attacker must authenticate with valid user credentials. The vulnerability is due to the incorrect implementation of a Bash shell command that allows role-based access control (RBAC) to be bypassed. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the Bash prompt. A successful exploit could allow the attacker to escalate their privilege level by executing commands that should be restricted to other roles. For example, a dev-ops user could escalate their privilege level to admin with a successful exploit of this vulnerability.

A vulnerability in a specific CLI command implementation of Cisco Nexus 9000 Series ACI Mode Switch Software could allow an authenticated, local attacker to escape a restricted shell on an affected device. The vulnerability is due to insufficient sanitization of user-supplied input when issuing a specific CLI command with parameters on an affected device. An attacker could exploit this vulnerability by authenticating to the device CLI and issuing certain commands. A successful exploit could allow the attacker to escape the restricted shell and execute arbitrary commands with root-level privileges on the affected device. This vulnerability only affects Cisco Nexus 9000 Series ACI Mode Switches that are running a release prior to 14.0(3d).

A vulnerability in the Cisco Nexus 9000 Series Fabric Switches running in Application-Centric Infrastructure (ACI) mode could allow an authenticated, local attacker to read arbitrary files on an affected device. The vulnerability is due to a lack of proper input and validation checking mechanisms of user-supplied input sent to an affected device. A successful exploit could allow the attacker unauthorized access to read arbitrary files on an affected device. This vulnerability has been fixed in version 14.0(1h).