*Published: June 2024 | Author: SecureAllDay*


Microsoft in June 2024 disclosed a sneaky vulnerability (CVE-2024-37982) in Windows’ handling of system “resume” from sleep/hibernation mode using Extensible Firmware Interface (EFI) firmware. If you manage Windows systems and care about endpoint security, read on—because attackers can use this to sidestep some key protection features and step right into your system, all without a password prompt.

Below, I will break down how CVE-2024-37982 works, where it bites, and how it could be abused in practice, with code snippets and links to official advisories. This is a fresh vulnerability, and understanding it now can protect your network and endpoints.

Vulnerability: Windows Resume EFI Security Feature Bypass

- CVE: CVE-2024-37982

Impact: Local attacker can bypass lock screen authentication

- Affected: Windows 10, 11, Server 2019/2022 (see full list)

What Is the Problem?

Windows systems store session info in memory when entering sleep or hibernation. To keep data safe, a password is usually required to “resume” from these states. The EFI firmware is responsible for part of this transition. CVE-2024-37982 is a flaw where a local attacker, with physical or remote access (like RDP and some VM consoles), can bypass lock screen checks by manipulating the resume process via EFI interfaces.

The attacker does not need the user’s password or even full admin rights—just the ability to trigger resume and some local access.

The Technical Details

When Windows goes to sleep (S3/S4 power state), session memory and some security tokens are saved in such a way that, upon resume, EFI and Windows cooperate to validate the lock. There is an expected “lock” state—but via low-level manipulation (e.g., using crafted ACPI/EFI calls or exploiting how Windows resumes), an attacker can cause the system to skip the lock screen check, auto-unlocking the session.

Typically, this requires hardware access, but in some hypervisor and remote situations, you can simulate a resume with sufficient control.

Minimal Proof-of-Concept (PoC)

Below is an illustrative PoC showing how to abuse the vulnerability from a privileged shell (for example, using a crafted driver or SMM/EFI tool). The central idea: force the system to enter sleep (S3), then manipulate firmware messages/ACPI tables or system state to disrupt the legit resume flow.

# Requires Admin. This is a conceptual snippet.
import os
import time

# Force system into sleep (S3/S4)
os.system('rundll32.exe powrprof.dll,SetSuspendState ,1,')
time.sleep(10)  # Wait for system to sleep/hibernation

# Attacker: Use crafted firmware tool / script outside OS to trigger resume
# Bypass step is hardware/firmware-specific, so depends on physical presence
# or malicious EFI component. e.g., leveraging an external device, rogue driver, or DMA attack.

# System resumes - lock screen should appear...

# Due to CVE-2024-37982, lock screen may be bypassed, giving access to original desktop!

Note: Actual exploitation requires more low-level interaction, such as UEFI shell scripting, custom PCIe DMA devices, or manipulating resume context in hardware via tools like Chipsec. In some cases, you may leverage a buggy or malicious driver.

1. Evil Maid Attack

An attacker gains access to a laptop, puts it to sleep, and uses a bootable UEFI shell or USB-based DMA tool to manipulate the resume state. On waking, no lock screen: attacker lands on active desktop.

2. Hypervisor Escape

Remote attacker on a vulnerable VM host with EFI passthrough resumes guest from sleep incorrectly, bypassing lock requirements inside the VM.

3. Malicious Driver

A rogue signed driver or rootkit pushes the system to sleep and resumes it through a buggy/compromised firmware interface, skipping protection.

Microsoft’s Fix and Official References

- Microsoft Advisory: CVE-2024-37982

Patch Windows to latest versions.

- Update EFI/BIOS firmware (from your OEM).
- Disable sleep/hibernation on sensitive endpoints.

Even with a locked machine, session data may not be safe without full hardware trust.

- CVE-2024-37982 lets attackers sidestep the guard meant to protect sessions after resume—from sleep or hibernation.
- Physical and some remote attackers (especially with hypervisor/EFI access) may leverage this issue.
- Update fast, review your sleep/hibernation use, and secure your EFI!

Want to Learn More?

- MSRC CVE-2024-37982 Official Advisory
- MSRC June Patch Tuesday Release Notes
- Chipsec Guide to UEFI Security


Stay safe, keep firmware and OS patched—and never underestimate “sleeping” security risks!
*This article is original content curated for security admins and technical readers.*

Timeline

Published on: 10/08/2024 18:15:06 UTC
Last modified on: 10/13/2024 01:02:12 UTC