CVE-2021-0099

Q: What is the severity of CVE-2021-0099?

CVE-2021-0099 has a CVSS score of 7.8 (HIGH). This firmware vulnerability in certain Intel processors allows authenticated local users to potentially escalate privileges by exploiting insufficient control flow management. It affects systems with specific Intel CPUs, requiring physical or local access to the machine. The impact is limited to environments where an attacker already has some level of access to the system.

7.8 HIGH

📋 TL;DR

This firmware vulnerability in certain Intel processors allows authenticated local users to potentially escalate privileges by exploiting insufficient control flow management. It affects systems with specific Intel CPUs, requiring physical or local access to the machine. The impact is limited to environments where an attacker already has some level of access to the system.

💻 Affected Systems

Products:

Intel Processors (specific models not publicly detailed in advisory)

Versions: Firmware versions prior to Intel's mitigation updates

Operating Systems: All operating systems running on affected Intel processors

Default Config Vulnerable: ⚠️ Yes

Notes: Affects systems with specific Intel CPUs; exact processor models are detailed in Intel's security advisory. Requires authenticated local access.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

An authenticated attacker gains full system control (root/admin privileges), potentially compromising sensitive data, installing persistent malware, or using the system as a pivot point in the network.

🟠

Likely Case

Privilege escalation from a standard user account to administrative/system-level access, allowing installation of unauthorized software, configuration changes, or access to protected resources.

🟢

If Mitigated

With proper access controls and monitoring, impact is limited to the specific compromised user account and can be detected through security monitoring.

🌐 Internet-Facing: LOW - This vulnerability requires local/authenticated access and cannot be exploited remotely over the internet.

🏢 Internal Only: MEDIUM - Internal users with authenticated access could exploit this, but requires physical or network access to the vulnerable system.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires detailed knowledge of processor microarchitecture and firmware internals. No public exploit code is available.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firmware updates provided by Intel and system manufacturers

Vendor Advisory: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00527.html

Restart Required: Yes

Instructions:

1. Check Intel advisory for affected processor models. 2. Contact system manufacturer for firmware/UEFI updates. 3. Apply firmware update following manufacturer instructions. 4. Reboot system to complete installation.

🔧 Temporary Workarounds

Restrict Physical Access

all

Limit physical access to vulnerable systems to authorized personnel only

Implement Least Privilege

all

Ensure users only have necessary privileges and monitor for privilege escalation attempts

🧯 If You Can't Patch

Isolate vulnerable systems in separate network segments
Implement strict access controls and monitoring for systems with vulnerable processors

🔍 How to Verify

Check if Vulnerable:

Check processor model and firmware version against Intel's advisory. Use 'wmic cpu get name' on Windows or 'cat /proc/cpuinfo' on Linux to identify CPU.

Check Version:

Windows: 'wmic bios get smbiosbiosversion', Linux: 'dmidecode -t bios' or check manufacturer-specific tools

Verify Fix Applied:

Verify firmware/UEFI version has been updated to manufacturer's latest version that includes Intel's mitigation.

📡 Detection & Monitoring

Log Indicators:

Unexpected firmware/UEFI access attempts
Privilege escalation events in security logs
Unusual system-level process execution

Network Indicators:

None - this is a local exploit

SIEM Query:

Search for privilege escalation events from standard user to SYSTEM/root, particularly involving firmware-related processes

📊 Metadata

CVE ID: CVE-2021-0099

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Published: February 9, 2022

Last Updated: May 5, 2025

🔗 References

https://security.netapp.com/advisory/ntap-20220210-0007/ Third Party Advisory
https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00527.html Vendor Advisory
https://security.netapp.com/advisory/ntap-20220210-0007/ Third Party Advisory
https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00527.html Vendor Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Atom C3308 by Intel

Atom C3336 by Intel

Atom C3338 by Intel

Atom C3338r by Intel

Atom C3436l by Intel

Atom C3508 by Intel

Atom C3538 by Intel

Atom C3558 by Intel

Atom C3558r by Intel

Atom C3708 by Intel

Atom C3750 by Intel

Atom C3758 by Intel

Atom C3758r by Intel

Atom C3808 by Intel

Atom C3830 by Intel

Atom C3850 by Intel

Atom C3858 by Intel

Atom C3950 by Intel

Atom C3955 by Intel

Atom C3958 by Intel

Cloud Backup by Netapp

Core I3 1000g1 by Intel

Core I3 1000g4 by Intel

Core I3 1005g1 by Intel

Core I3 10100 by Intel

Core I3 10100e by Intel

Core I3 10100f by Intel

Core I3 10100t by Intel

Core I3 10100te by Intel

Core I3 10100y by Intel

Core I3 10105 by Intel

Core I3 10105f by Intel

Core I3 10105t by Intel

Core I3 10110u by Intel

Core I3 10110y by Intel

Core I3 10300 by Intel

Core I3 10300t by Intel

Core I3 10305 by Intel

Core I3 10305t by Intel

Core I3 10320 by Intel

Core I3 10325 by Intel

Core I3 11100he by Intel

Core I3 1110g4 by Intel

Core I3 1115g4 by Intel

Core I3 1115g4e by Intel

Core I3 1115gre by Intel

Core I3 1120g4 by Intel

Core I3 1125g4 by Intel

Core I3 6006u by Intel

Core I3 6098p by Intel

Core I3 6100 by Intel

Core I3 6100e by Intel

Core I3 6100h by Intel

Core I3 6100t by Intel

Core I3 6100te by Intel

Core I3 6100u by Intel

Core I3 6102e by Intel

Core I3 6157u by Intel

Core I3 6167u by Intel

Core I3 6300 by Intel

Core I3 6300t by Intel

Core I3 6320 by Intel

Core I3 7020u by Intel

Core I3 7100 by Intel

Core I3 7100e by Intel

Core I3 7100h by Intel

Core I3 7100t by Intel

Core I3 7100u by Intel

Core I3 7101e by Intel

Core I3 7101te by Intel

Core I3 7102e by Intel

Core I3 7130u by Intel

Core I3 7167u by Intel

Core I3 7300 by Intel

Core I3 7300t by Intel

Core I3 7320 by Intel

Core I3 7350k by Intel