External risk intelligence

Microsoft Windows Installer Privilege Escalation Advisory.

CVE advisoryKnown Exploit

CVE-2021-41379

A vulnerability in Windows Installer allows an attacker with local access to escalate privileges. This could impact system integrity and lead to unauthorized actions. The risk to organizations is heightened as this vulnerability is listed among known exploited vulnerabilities.

1Halo Surface Signal

Microsoft Windows 10 1507

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External exposure likelihood

Halo Surface Signal score for CVE-2021-41379

This is a local privilege escalation vulnerability within the Windows Installer service. It requires an attacker to already have local access to the system to exploit, meaning there is no network-reachable or internet-facing attack surface.

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the Windows Installer allows for an elevation of privilege. This means an attacker with existing access to a system could potentially gain higher-level permissions than they should have. The core issue lies within how the Windows Installer handles certain operations, creating a weakness that can be exploited. Such an exploit could impact the integrity of systems by allowing unauthorized actions, potentially leading to broader business risks if sensitive data or critical functions are compromised.

  • Vulnerable component: Windows Installer
  • Core weakness: Improper handling of operations
  • Main business impact: Unauthorized system access or control

Attack Path

How an attacker could exploit the issue

This vulnerability allows an attacker to gain higher privileges on a system. The attack begins when an attacker with low-level access on a target machine finds a way to interact with the Windows Installer. This interaction can then be manipulated to execute actions with elevated permissions, potentially leading to unauthorized system modifications or data access.

  • Local system access required.
  • Attacker manipulates installer.
  • Gain elevated privileges.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability impacts the Windows Installer service, potentially allowing an attacker with local access to gain elevated privileges. Exploiting this requires an attacker to already be present on the affected system. The risk to the organization is elevated due to its inclusion in a catalog of known exploited vulnerabilities, suggesting active use in real-world attacks.

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

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability affects Windows Installer and could allow an attacker with local access to elevate their privileges on a system. This could lead to unauthorized access or modification of sensitive data and systems. Organizations should prioritize understanding their exposure and implementing vendor-provided fixes to mitigate risk.

  • Find all affected Windows assets.
  • Reduce exposure by limiting local access.
  • Apply vendor fixes and validate.
  • Monitor for related activity.

Frequently asked questions

What is the Windows Installer and what is its function?

The Windows Installer is a core component of Microsoft Windows responsible for the installation, maintenance, and removal of software applications. It ensures that applications are correctly set up and managed on a user's system.

What type of vulnerability does CVE-2021-41379 represent?

CVE-2021-41379 describes an Elevation of Privilege vulnerability. This means a weakness exists that allows a user with limited system access to obtain higher-level permissions.

How can an attacker leverage the CVE-2021-41379 vulnerability?

An attacker with existing local access to a system can exploit this weakness by interacting with the Windows Installer. This interaction can be manipulated to execute commands with elevated privileges, potentially leading to unauthorized system control.

What is the significance of CVE-2021-41379 being listed on the Halo Surface Signal?

The Halo Surface Signal indicates this vulnerability is considered internal because it requires local system access for exploitation. It is not an internet-facing threat, meaning an attacker must already be on the target machine.

What steps should organizations take to address CVE-2021-41379?

Organizations should identify all affected Windows systems, restrict local access where possible, and promptly apply vendor-provided updates. Validating that the fixes have been implemented and monitoring for any related suspicious activity are also crucial steps.

References