CVE-2024-0762: Phoenix SecureCore Buffer Overflow Flaw

CVE-2024-0762 Overview

CVE-2024-0762 is a buffer overflow vulnerability in Phoenix SecureCore™ UEFI firmware affecting a wide range of Intel platforms. The vulnerability exists in unsafe UEFI variable handling, which could allow an authenticated local attacker to escalate privileges and potentially execute arbitrary code at the firmware level. This type of firmware-level vulnerability is particularly dangerous as it operates below the operating system, making it difficult to detect and remediate through traditional security tools.

Critical Impact

Successful exploitation could allow attackers to achieve persistent code execution at the UEFI firmware level, bypassing operating system security controls and potentially surviving OS reinstallation.

Affected Products

• Phoenix SecureCore™ for Intel Kaby Lake: versions 4.0.1.1 to 4.0.1.998
• Phoenix SecureCore™ for Intel Coffee Lake: versions 4.1.0.1 to 4.1.0.562
• Phoenix SecureCore™ for Intel Ice Lake: versions 4.2.0.1 to 4.2.0.323
• Phoenix SecureCore™ for Intel Comet Lake: versions 4.2.1.1 to 4.2.1.287
• Phoenix SecureCore™ for Intel Tiger Lake: versions 4.3.0.1 to 4.3.0.236
• Phoenix SecureCore™ for Intel Jasper Lake: versions 4.3.1.1 to 4.3.1.184
• Phoenix SecureCore™ for Intel Alder Lake: versions 4.4.0.1 to 4.4.0.269
• Phoenix SecureCore™ for Intel Raptor Lake: versions 4.5.0.1 to 4.5.0.218
• Phoenix SecureCore™ for Intel Meteor Lake: versions 4.5.1.1 to 4.5.1.15

Discovery Timeline

• May 14, 2024 - CVE-2024-0762 published to NVD
• September 29, 2025 - Last updated in NVD database

Technical Details for CVE-2024-0762

Vulnerability Analysis

This vulnerability resides in the UEFI variable handling routines within Phoenix SecureCore™ firmware. UEFI variables are used to store configuration data and communicate between the firmware and the operating system. The flaw occurs when the firmware processes specially crafted UEFI variable data without proper bounds checking, leading to a classic buffer overflow condition.

An attacker with local access and low-level privileges can craft malicious UEFI variable data that exceeds expected buffer boundaries. When the vulnerable firmware component processes this data, it overwrites adjacent memory regions, potentially corrupting control flow data structures. This enables the attacker to redirect execution to attacker-controlled code, achieving arbitrary code execution in System Management Mode (SMM) or other privileged firmware contexts.

The impact of firmware-level code execution is severe. Code running at the UEFI level operates with the highest privilege, executing before and independently of the operating system. This allows attackers to install persistent implants that survive operating system reinstallation, disable security features like Secure Boot, or manipulate hardware directly.

Root Cause

The root cause is a buffer overflow vulnerability (CWE-120) resulting from insufficient bounds checking when handling UEFI variables. The firmware code fails to validate the length of user-supplied data before copying it into fixed-size buffers, allowing an attacker to overflow the destination buffer with excess data.

Attack Vector

The attack requires local access to the target system with the ability to interact with UEFI variable services. An attacker would typically:

1. Gain initial access to the target system with local user privileges
2. Identify the vulnerable UEFI variable handling routine
3. Craft malicious UEFI variable data designed to trigger the buffer overflow
4. Submit the crafted data through UEFI runtime services
5. The overflow corrupts memory, potentially allowing code execution in SMM or other firmware contexts
6. Establish persistence at the firmware level, surviving OS-level security controls

The vulnerability requires local access, meaning an attacker must first compromise the system through other means before exploiting this flaw for privilege escalation and persistence.

Detection Methods for CVE-2024-0762

Indicators of Compromise

• Unexpected changes to UEFI variables or firmware configuration settings
• Anomalous firmware behavior during boot sequence or runtime
• Modifications to Secure Boot database entries or policies
• Presence of unknown UEFI drivers or modules in the firmware image
• System instability or unexpected behavior that persists across OS reinstallation

Detection Strategies

• Deploy firmware integrity monitoring solutions that can detect unauthorized modifications to UEFI firmware
• Implement hardware security modules (HSMs) or TPM-based attestation to verify firmware integrity at boot
• Utilize endpoint detection and response (EDR) solutions with firmware-level visibility capabilities
• Regularly audit UEFI variable stores for unexpected or malicious entries

Monitoring Recommendations

• Enable and monitor UEFI Secure Boot violation events in system logs
• Implement automated firmware version inventory and vulnerability scanning across the enterprise
• Monitor for unusual system reboots or firmware update activities that may indicate exploitation attempts
• Deploy SentinelOne agents with firmware protection capabilities to detect below-OS threats

How to Mitigate CVE-2024-0762

Immediate Actions Required

• Inventory all systems using Phoenix SecureCore™ firmware on affected Intel platforms and prioritize patching
• Contact your system OEM vendor to obtain firmware updates that include the fix for CVE-2024-0762
• Enable UEFI Secure Boot and configure firmware passwords to restrict unauthorized firmware modifications
• Apply the principle of least privilege to limit local access that could be used to exploit this vulnerability

Patch Information

Phoenix Technologies has released updated firmware versions to address this vulnerability. The following minimum versions contain the fix:

Organizations should obtain firmware updates from their system OEM vendor (e.g., Lenovo, Dell, HP) rather than directly from Phoenix Technologies. For detailed information, refer to the Phoenix Security Notification and the Eclypsium Blog Analysis.

Workarounds

• If patches are not immediately available, restrict physical and administrative access to affected systems
• Enable firmware write protection features where available to prevent unauthorized modifications
• Implement network segmentation to isolate systems that cannot be immediately patched
• Deploy additional endpoint monitoring focused on detecting firmware-level anomalies

# Verify current firmware version on Linux systems
sudo dmidecode -t bios | grep -E "(Vendor|Version|Release)"

# Check UEFI Secure Boot status
mokutil --sb-state

# List UEFI variables (requires root privileges)
efivar -l | grep -i phoenix