CISA Urges Software Makers to Eliminate OS Command Injection Flaws

CVE-2024-20399 is a command injection flaw (CWE-78) in the CLI of Cisco NX-OS Software, caused by insufficient validation of arguments passed to specific configuration CLI commands. An authenticated attacker who already holds Administrator credentials can trigger it by submitting crafted input as the argument of an affected configuration command, gaining the ability to execute arbitrary commands as root on the device's underlying operating system. Because Administrator access is required, the flaw is effectively a privilege-escalation issue following credential compromise, and it grants no additional privilege on Nexus 3000 Series, Nexus 7000 Series running NX-OS 8.1(1) or later, and Nexus 9000 Series in standalone NX-OS mode, which already allow administrative bash-shell access to the OS. Any organization running affected NX-OS on Cisco Nexus switching is in scope, with the practical risk concentrated in environments where admin credentials may have been stolen. Exploitation has been observed in the wild: the China-linked group 'Velvet Ant' (associated with Salt Typhoon) used it as a zero-day to compromise U.S. ISPs and telecom providers, and CISA added it to the Known Exploited Vulnerabilities catalog on 2024-07-02.

Do: Upgrade affected Nexus switches to a fixed NX-OS release per Cisco's security advisory, as required by the CISA KEV listing (apply mitigations per vendor instructions or discontinue use if fixes are unavailable). Restrict and audit Administrator-level CLI access on NX-OS devices, and hunt for suspicious configuration-command activity or unexplained root-level actions, given Velvet Ant/Salt Typhoon targeting of telecom and ISP networks. For Nexus 3000, Nexus 7000 (8.1(1)+), and Nexus 9000 standalone-mode devices the flaw adds no privilege, but patching is still recommended.

Ivanti Connect Secure (formerly Pulse Connect Secure) and Ivanti Policy Secure appliances contain a command injection flaw (CWE-77) in their web components, triggered when an authenticated administrator sends crafted requests to the appliance. The bug can be chained with the separate authentication bypass CVE-2023-46805, allowing an unauthenticated attacker to achieve the same result. Successful exploitation lets an attacker execute arbitrary commands and code on the appliance, providing a foothold into the networks behind the VPN or network access control gateway. Any organization running these appliances, typically enterprises and government agencies often deployed directly on the internet perimeter, is affected. Exploitation is confirmed in the wild: the flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2024-01-10 with known ransomware use and EPSS assigns a 100% probability of exploitation within 30 days, although no public proof-of-concept is available.

Do: Apply Ivanti's mitigations or patched builds immediately per vendor instructions, addressing the chained authentication bypass CVE-2023-46805 at the same time, and discontinue or restrict use of any appliance for which mitigations are unavailable, especially if it is internet-facing. Because exploitation with ransomware use is known, assume compromise is possible: review appliance web logs for suspicious requests and run Ivanti's integrity-checking guidance to verify appliance images before and after remediation. Where feasible, restrict direct internet exposure of the appliance web interface and monitor for further vendor advisories.

Palo Alto Networks PAN-OS contains a command injection flaw (CWE-77, with improper input validation per CWE-20) in its GlobalProtect feature, allowing an unauthenticated attacker to execute arbitrary operating-system commands with root privileges on the affected firewall. The flaw is triggered through the GlobalProtect interface, which in most deployments is reachable from untrusted networks, so no valid user credentials or prior access are required. Successful exploitation yields full root control of the firewall, the most powerful position in a network perimeter, enabling traffic interception, configuration tampering, and use as a foothold for further compromise. All PAN-OS firewalls running affected releases with the GlobalProtect feature are exposed; CISA added the issue to the KEV catalog on 2024-04-12 with ransomware use noted, and EPSS puts the 30-day exploitation probability at 100% (100th percentile). No public proof-of-concept is recorded in the source data, but confirmed in-the-wild exploitation makes patching urgent.

Do: Apply the PAN-OS patches released in Palo Alto Networks' bulletin according to its published patch schedule, prioritizing internet-facing firewalls. Until patched, enable the vendor's Threat Prevention signatures as required by CISA KEV, restrict exposure of the GlobalProtect interface to trusted sources where possible, and review logs and device configuration for signs of compromise given confirmed exploitation with known ransomware use.