Cisco HyperFlex HX Web-Based Management Interface Remote Command Injection Vulnerability (CVE-2021-1497) Analysis and Mitigation Guide

1. Vulnerability Overview & Root Cause

This vulnerability (CVE-2021-1497) is a critical Command Injection vulnerability in the web-based management interface of Cisco HyperFlex HX Data Platform. The root cause lies in the web application's failure to properly validate or sanitize user-supplied input before passing it to internal system shells for execution (CWE-78). An unauthenticated, remote attacker can exploit this by sending crafted HTTP requests, allowing them to execute arbitrary operating system commands with the privileges of the web server process.

2. Exploitation Mechanics & Attack Scenario

An attacker with network access to the Cisco HyperFlex controller VM's web management interface (TCP 80/443) targets vulnerable API endpoints or servlets that process input parameters without sanitization. By embedding shell metacharacters (such as ;, &, |, or backticks) along with malicious payloads into the HTTP request parameters, the attacker forces the underlying operating system to execute their commands. This can be used to establish a reverse shell, download malware, or modify system configurations. Given its inclusion in the CISA KEV catalog and an EPSS score of 0.9992, this vulnerability is highly attractive to threat actors and easily automated.

3. Infrastructure & Business Impact

Cisco HyperFlex serves as the core Hyperconverged Infrastructure (HCI) for enterprise virtualization environments. A compromise of the HyperFlex controller VM allows attackers to move laterally across the hypervisor and virtual machines. This poses a severe threat to business continuity, potentially leading to full infrastructure takeover, data exfiltration, ransomware deployment, or unauthorized resource utilization.