CVE-2021-0115 Overview
CVE-2021-0115 is a buffer overflow vulnerability [CWE-120] in the firmware shipped with a broad range of Intel processors. The flaw permits a privileged local user to corrupt firmware memory and potentially escalate privileges beyond the operating system boundary. Intel disclosed the issue in advisory INTEL-SA-00527, and NetApp re-issued advisory NTAP-20220210-0007 for FAS/AFF BIOS and Cloud Backup products that incorporate affected Intel silicon. Because the defect resides in processor firmware, exploitation impacts confidentiality, integrity, and availability of the platform itself, not just operating system processes.
Critical Impact
A privileged local attacker can trigger the buffer overflow in Intel processor firmware to escalate privileges and gain control below the operating system layer, affecting hundreds of Core, Xeon, Atom, and embedded processor models.
Affected Products
- Intel Core processors (6th through 11th generation), including Core i3, i5, i7, i9, and Core M families
- Intel Xeon processors, including Xeon Bronze, Silver, Gold, Platinum, D, E, and W series
- Intel Atom C3000 series and NetApp FAS/AFF BIOS plus NetApp Cloud Backup
Discovery Timeline
- 2022-02-09 - CVE-2021-0115 published to NVD
- 2025-05-05 - Last updated in NVD database
Technical Details for CVE-2021-0115
Vulnerability Analysis
The weakness is a classic buffer overflow [CWE-120] located in firmware code that executes as part of the Intel processor initialization and runtime services. A privileged user with local access can supply input that exceeds the bounds of an internal buffer, overwriting adjacent firmware memory. Because firmware runs at a privilege level higher than the operating system kernel, successful corruption can lead to escalation that bypasses operating system security boundaries. The attack does not require user interaction and operates within a single security scope, producing high impact to confidentiality, integrity, and availability.
Root Cause
The root cause is improper restriction of operations within the bounds of a memory buffer in the affected processor firmware. The firmware code fails to validate input size before copying data into a fixed-length buffer, allowing an attacker who already holds elevated operating system privileges to overflow that buffer and influence firmware execution state.
Attack Vector
Exploitation requires local access and high privileges, meaning the attacker must already be running as an administrator, root, or equivalent on the host. The attacker invokes a firmware interface, such as a model-specific register write, a vendor service, or a BIOS-level call path, with crafted parameters that overflow the vulnerable buffer. No user interaction is required, and the impact remains within the same security scope as the firmware itself, which sits below the operating system.
The vulnerability is described in prose because no public proof-of-concept code has been released. See the Intel Security Advisory SA-00527 for technical guidance.
Detection Methods for CVE-2021-0115
Indicators of Compromise
- Unexpected BIOS, UEFI, or microcode version mismatches between identical hardware models in the fleet.
- System Management Mode (SMM) handlers, firmware drivers, or platform services crashing or producing machine check exceptions without a hardware fault.
- Privileged processes invoking firmware interfaces such as WRMSR, vendor SMI handlers, or BIOS update routines outside of approved patch windows.
Detection Strategies
- Inventory installed processor models against the Intel SA-00527 list and correlate with current BIOS and microcode versions to identify unpatched systems.
- Monitor administrative process activity that touches firmware update utilities, flashrom, vendor BIOS tools, or kernel modules that interact with MSRs.
- Alert on unauthorized loading of kernel drivers that expose direct hardware access, which is a common precursor to firmware-level exploitation.
Monitoring Recommendations
- Collect BIOS version, microcode revision, and platform firmware attributes through endpoint telemetry and centralize for drift detection.
- Forward privileged process creation events and driver-load events to a security data lake for retroactive hunting once new firmware indicators emerge.
- Track local privilege escalation attempts and lateral movement that could position an attacker to reach the local administrator state required for exploitation.
How to Mitigate CVE-2021-0115
Immediate Actions Required
- Identify all systems containing affected Intel processors using vendor inventory tools and the Intel SA-00527 product list.
- Apply the BIOS and firmware updates published by the OEM (Dell, HP, Lenovo, Supermicro, NetApp, and others) that integrate the Intel-supplied fixes.
- Restrict local administrative access and enforce least privilege so that the high-privilege precondition required by this vulnerability is harder to satisfy.
Patch Information
Intel released firmware updates addressing CVE-2021-0115 through OEM channels. Refer to the Intel Security Advisory SA-00527 for the authoritative list of affected processor families and recommended firmware versions. NetApp customers should consult the NetApp Security Advisory NTAP-20220210-0007 for FAS/AFF BIOS and Cloud Backup remediation guidance.
Workarounds
- Limit administrative privileges and require multi-person approval for firmware modification operations until patches can be deployed.
- Enable platform integrity features such as Secure Boot, measured boot, and TPM-backed attestation to detect unauthorized firmware changes.
- Isolate systems that cannot be updated promptly into segmented networks with stricter access controls and enhanced monitoring.
# Example: verify current BIOS and microcode versions on Linux
sudo dmidecode -s bios-version
sudo dmidecode -s bios-release-date
cat /proc/cpuinfo | grep -E 'model name|microcode' | sort -u
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
