External risk intelligence

Microsoft Windows Elevation of Privilege Vulnerability

CVE advisoryKnown Exploit

CVE-2021-41357

A privilege escalation vulnerability in Win32k affects Microsoft Windows. This could allow an attacker with local access to gain elevated privileges on a system, potentially leading to unauthorized access and data compromise. The business risk involves loss of system control and data integrity.

1Halo Surface Signal

Microsoft Windows 10 2004

before 10.0.19041.1288before 10.0.19042.1288before 10.0.19043.1288before 10.0.22000.258before 10.0.20348.288

External exposure likelihood

Halo Surface Signal score for CVE-2021-41357

This is a local privilege escalation vulnerability within the Windows Win32k subsystem. It requires a user or process to already have local access to the system to exploit, making it inherently local rather than remotely reachable via the public internet.

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability exists within the Win32k component of Microsoft Windows. This flaw could allow an attacker to escalate their privileges on an affected system. Such an escalation could potentially grant unauthorized access to sensitive data or system functions.

  • Vulnerable: Win32k component
  • Flaw: Privilege escalation
  • Impact: Unauthorized system access

Attack Path

How an attacker could exploit the issue

A local privilege escalation vulnerability in Win32k could allow an attacker to gain higher system privileges. This typically occurs when an attacker with existing access to a system can execute malicious code. The vulnerability can be triggered by specific actions, leading to unauthorized control or impact.

  • Exposure condition: Local access to the system.
  • Attacker starting point: Low-privileged user account.
  • Trigger and result: Execute code, gain elevated privileges.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in Win32k could allow an attacker with local access to escalate privileges, potentially gaining administrative control of an affected system. The difficulty of exploitation is considered low, and the potential for significant damage to data and systems presents a considerable business risk. Organizations should treat this as a high-priority item requiring immediate attention and remediation.

  • Likely attacker skill level: Low.
  • Required access or conditions: Local system access.
  • Business risk or urgency: High.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the Win32k component of Windows could allow an attacker to gain elevated privileges on an affected system. Organizations should prioritize understanding their exposure to this vulnerability to mitigate potential business risk. Prompt action to address this issue is advisable to maintain system integrity and security.

  • Identify systems running the affected Windows versions.
  • Isolate or reduce access to vulnerable assets.
  • Apply vendor updates, verify remediation, and monitor.

Frequently asked questions

What is the Win32k component in Microsoft Windows?

Win32k is a critical component of the Windows operating system's kernel-mode graphics subsystem. It handles tasks related to user interface elements like windows, menus, and icons, and is fundamental to how applications interact with the graphical environment. This vulnerability resides within this core part of Windows.

What weakness class does CVE-2021-41357 represent?

CVE-2021-41357 is an Elevation of Privilege vulnerability. This means that an attacker who can trigger this flaw could gain greater control and permissions on an affected Windows system than they are normally entitled to, potentially bypassing security restrictions.

How might an attacker exploit CVE-2021-41357?

Exploiting this vulnerability typically requires an attacker to already have some level of access to the targeted Windows system. They would then need to execute specific code or perform certain actions that trigger the flaw within the Win32k component to gain elevated privileges. A user with low-level access could potentially exploit this.

How relevant is CVE-2021-41357 to my organization?

This is an internal vulnerability, meaning it generally requires an attacker to have existing local access to the system. While it doesn't expose systems directly to the public internet, any organization with Windows systems where local access is a concern should pay attention, as it could allow an attacker to escalate their privileges.

What should I do first if my organization runs affected Windows versions?

The immediate first step is to identify which systems within your organization are running the affected versions of Windows. Following that, consult Microsoft's security guidance for CVE-2021-41357 to apply the necessary updates and remediations to protect your systems.

References