CVE-2021-1497
Cisco HyperFlex HX Installer Virtual Machine Command Injection Vulnerability
Description
CVE-2021-1497 is a CRITICAL command injection vulnerability affecting Cisco HyperFlex HX Data Platform, carrying a CVSS 3.1 score of 9.8. The web-based management interface of Cisco HyperFlex HX contains insufficient input validation that allows an unauthenticated, remote attacker to perform command injection attacks, executing arbitrary commands as the root user on affected devices. Affected products include Cisco HyperFlex HX Data Platform (< 4.0(2e) and >= 4.5, < 4.5(2a)). This CVE is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of 2021-11-17. With an EPSS score of 0.94363 (99.96th percentile), this vulnerability demonstrates extremely high real-world exploitation probability and requires immediate remediation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| cisco | hyperflex hx data platform | < 4.0\(2e\); >= 4.5, < 4.5\(2a\) |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- http://packetstormsecurity.com/files/162976/Cisco-HyperFlex-HX-Data-Platform-Command-Execution.html(Exploit, Third Party Advisory, VDB Entry)
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hyperflex-rce-TjjNrkpR(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1497(US Government Resource)
Weakness Type
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CVE-2021-1497 is classified under CWE-78 — OS Command Injection. OS Command Injection occurs when software constructs all or part of an operating system command using externally-influenced input without proper neutralization of special elements. This allows attackers to inject arbitrary commands that are then executed by the underlying operating system, often with elevated privileges. Command injection is one of the most severe vulnerability classes as it directly leads to system compromise.
In the context of Cisco HyperFlex HX, this weakness is critical because the command injection vulnerability in the web-based management interface allows unauthenticated attackers to execute commands as the root user. This means complete system compromise is possible without any prior authentication, and the attacker gains the highest possible privilege level on the affected HyperFlex node.
Learn more: CWE-78 — Improper Neutralization of Special Elements used in an OS Command
Impact Analysis
CVE-2021-1497 carries a CVSS 3.1 score of 9.8 (CRITICAL) with Unchanged Scope.
Confidentiality (HIGH): Successful exploitation grants the attacker root-level access to the HyperFlex HX system, enabling complete access to all data stored and processed on the hyperconverged infrastructure node, including virtual machine data, configuration files, and credentials.
Integrity (HIGH): With root access, attackers can modify any system configuration, install persistent backdoors, alter virtual machine images, or manipulate the hyperconverged infrastructure to affect all hosted workloads.
Availability (HIGH): Complete disruption of the HyperFlex HX platform is possible, including shutting down virtual machines, destroying data, or rendering the entire hyperconverged infrastructure node inoperable.
Scope Unchanged: The vulnerability's scope is Unchanged (U), meaning impact is technically contained within the HyperFlex HX component. However, as a hyperconverged infrastructure platform, compromise of a HyperFlex node effectively impacts all workloads running on that infrastructure.
With an EPSS score of 0.94363 (99.96th percentile), this vulnerability ranks among the most exploited vulnerabilities tracked globally.
Exploit Maturity
CVE-2021-1497 has confirmed active exploitation in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog.
Exploit status: Public exploit code is available for this vulnerability, including a Metasploit module that automates exploitation. The EPSS score of 0.94363 (99.96th percentile) reflects the extremely high exploitation activity and the low barrier to attack.
Ransomware association: As of the latest KEV data, no direct ransomware association has been confirmed for CVE-2021-1497. However, the ability to execute commands as root on hyperconverged infrastructure nodes provides an ideal platform for deploying ransomware across an organization's virtualized environment.
Attack surface: The web-based management interface is the attack surface. Organizations with internet-exposed HyperFlex management interfaces are at critical risk. Even internal-facing interfaces may be targeted by attackers who have gained initial network access.
KEV deadline: CISA required federal agencies to remediate this vulnerability by 2021-11-17. The critical severity and availability of public exploits make immediate patching essential for all organizations.
Remediation
- Apply Cisco security patches immediately. Update Cisco HyperFlex HX Data Platform to version 4.0(2e) or later for the 4.0.x branch, or 4.5(2a) or later for the 4.5.x branch. Consult Cisco Security Advisory cisco-sa-hyperflex-rce-TjjNrkpR for specific guidance.
- Identify all HyperFlex HX installations. Inventory all Cisco HyperFlex HX nodes in your environment and verify their software versions against the affected version ranges.
- Restrict management interface access. Ensure the HyperFlex web-based management interface is not accessible from the internet. Restrict access to dedicated management networks with strict access controls.
- Monitor for exploitation attempts. Review web server logs on HyperFlex nodes for suspicious HTTP requests targeting the management interface. Look for command injection patterns in request parameters.
- Investigate potentially compromised systems. If HyperFlex nodes were running vulnerable versions with accessible management interfaces, conduct a thorough forensic investigation. Check for unauthorized root access, new user accounts, modified system files, and persistent backdoors.
- Implement network segmentation. Isolate HyperFlex management networks from general user networks and ensure proper micro-segmentation is in place to limit lateral movement.
- Update detection and monitoring tools. Ensure IDS/IPS and endpoint detection systems have signatures for CVE-2021-1497 exploitation attempts.
Technical Details
CVE-2021-1497 is a CRITICAL-severity vulnerability in Cisco HyperFlex HX Data Platform that can be exploited remotely over the network. The attack complexity is low, requiring no specialized conditions. No prior authentication or privileges are needed. No user interaction is required, enabling fully automated exploitation.
Technical mechanism: The vulnerability exists in the web-based management interface of Cisco HyperFlex HX due to insufficient input validation. User-supplied input to the management interface is not properly sanitized before being passed to operating system command execution functions. An attacker can craft HTTP requests containing OS command injection payloads that are executed by the underlying system with root privileges.
Execution context: Commands injected through this vulnerability execute as the root user, providing the highest possible privilege level on the affected system. This grants complete control over the HyperFlex node, including all virtual machine resources managed by the platform.
Related vulnerabilities: CVE-2021-1497 is part of a set of command injection vulnerabilities affecting the HyperFlex HX management interface. CVE-2021-1498 addresses a related but distinct command injection flaw in the same product.
CVSS 3.1 vector analysis: The vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H reflects a network-accessible attack with low complexity, no privileges required, no user interaction needed, and maximum impact across all three CIA triad dimensions.
Frequently Asked Questions
Is CVE-2021-1497 being actively exploited?
Yes, CVE-2021-1497 is actively exploited in the wild. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and has an EPSS score of 0.94363 (99.96th percentile). Public exploit code, including a Metasploit module, is available, making exploitation accessible to a wide range of threat actors.
What products are affected by CVE-2021-1497?
Cisco HyperFlex HX Data Platform versions prior to 4.0(2e) and versions 4.5.x prior to 4.5(2a) are affected. Organizations should check all HyperFlex HX nodes in their infrastructure and verify the running software version.
How do I fix CVE-2021-1497?
Update Cisco HyperFlex HX Data Platform to version 4.0(2e) or later (for 4.0.x branch) or 4.5(2a) or later (for 4.5.x branch) as described in Cisco advisory cisco-sa-hyperflex-rce-TjjNrkpR. Restrict access to the management interface and investigate for signs of prior compromise.
How severe is CVE-2021-1497?
CVE-2021-1497 is rated CRITICAL with a CVSS 3.1 score of 9.8. It allows unauthenticated remote command execution as root on HyperFlex HX nodes. The combination of no authentication requirement, root-level execution, and public exploit availability makes this an extremely high-priority vulnerability.
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