CVE-2023-42772: Intel UEFI Privilege Escalation Flaw

CVE-2023-42772 Overview

CVE-2023-42772 is an untrusted pointer dereference vulnerability in the UEFI firmware for some Intel reference processors. This firmware-level security flaw allows a privileged user to potentially enable escalation of privilege through local access. The vulnerability affects the foundational boot firmware that executes before the operating system loads, making it particularly concerning from a security perspective.

Critical Impact

A privileged attacker with local access can exploit this UEFI firmware vulnerability to escalate privileges, potentially gaining persistent control at the firmware level that survives operating system reinstallation.

Affected Products

• Intel Reference Processor UEFI Firmware
• Systems utilizing affected Intel reference processor implementations
• NetApp systems (per NetApp Security Advisory)

Discovery Timeline

• 2024-09-16 - CVE CVE-2023-42772 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2023-42772

Vulnerability Analysis

This vulnerability is classified as CWE-822: Untrusted Pointer Dereference. The flaw exists within the UEFI firmware for Intel reference processors, where the firmware improperly handles pointer values that may originate from untrusted sources. When the firmware dereferences a pointer without adequate validation, an attacker with privileged local access can manipulate the pointer to reference arbitrary memory locations.

UEFI firmware operates in System Management Mode (SMM), which has the highest privilege level on x86 systems. Exploitation at this level bypasses all operating system security controls and can result in persistent compromise that survives OS reinstallation.

Root Cause

The root cause is improper validation of pointer values before dereference operations within the UEFI firmware code. The firmware fails to adequately verify that pointer values point to legitimate and expected memory regions. This allows a privileged attacker to supply a malicious pointer value that, when dereferenced, can read from or write to arbitrary memory locations within the firmware's execution context.

Attack Vector

The attack requires local access to the system and elevated privileges. An attacker would need to:

1. Gain local access with administrative or system-level privileges on the affected system
2. Interact with the UEFI firmware through available interfaces (such as UEFI runtime services, SMI handlers, or during the boot process)
3. Supply a crafted pointer value to a vulnerable firmware component
4. Trigger the untrusted pointer dereference to achieve arbitrary read/write capabilities
5. Leverage the memory corruption to escalate privileges within the firmware context

The vulnerability can be exploited to achieve persistence below the operating system level. Firmware-level implants established through this vulnerability would survive operating system reinstallation, disk formatting, and most forensic remediation efforts.

Detection Methods for CVE-2023-42772

Indicators of Compromise

• Unexpected UEFI firmware modifications or integrity check failures
• Anomalous SMI (System Management Interrupt) activity patterns
• Firmware version mismatches compared to known-good baselines
• Unexpected runtime services behavior or memory access patterns

Detection Strategies

• Implement UEFI firmware integrity monitoring using hardware-backed attestation mechanisms such as Intel TXT or TPM-based measurements
• Deploy endpoint detection solutions capable of monitoring pre-boot and firmware-level activities
• Compare firmware images against vendor-provided golden images using secure boot logs and measurements
• Monitor for unauthorized firmware update attempts or BIOS flash operations

Monitoring Recommendations

• Enable Secure Boot and verify its configuration remains intact across system restarts
• Configure TPM-based boot measurement logging and regularly audit PCR (Platform Configuration Register) values
• Implement centralized firmware version tracking across the enterprise
• Monitor system event logs for UEFI-related errors or unexpected firmware service calls

How to Mitigate CVE-2023-42772

Immediate Actions Required

• Review the Intel Security Advisory SA-01071 for specific patch guidance and affected product details
• Apply firmware updates provided by Intel and system OEMs as they become available
• Restrict local administrative access to affected systems to reduce the attack surface
• Enable and enforce Secure Boot to help prevent unauthorized firmware modifications

Patch Information

Intel has released security advisories addressing this vulnerability. Organizations should consult the Intel Security Advisory SA-01071 for detailed patch information. NetApp customers should additionally review the NetApp Security Advisory NTAP-20241011-0009 for guidance specific to NetApp products.

Firmware updates must be obtained from the system OEM, as Intel provides reference firmware that is then customized by hardware manufacturers. Contact your system vendor for the appropriate UEFI firmware update for your specific hardware platform.

Workarounds

• Limit physical and administrative access to affected systems until patches can be applied
• Enable firmware write protection features if supported by the hardware platform
• Implement strong authentication and access controls for any systems with the affected firmware
• Consider network segmentation to isolate high-value systems running vulnerable firmware

System administrators should prioritize firmware updates for this vulnerability given the potential for persistent, firmware-level compromise that operates below the visibility of traditional endpoint security tools.