External risk intelligence

Windows Local Privilege Escalation Vulnerability

CVE advisoryKnown Exploit

CVE-2015-2546

A local user can gain elevated privileges on affected Windows systems by running a crafted application. This can lead to unauthorized access and control of systems, potentially impacting data and business operations. Organizations should identify affected systems and apply vendor updates.

1Halo Surface Signal

Memory Corruption

Microsoft Windows 10 1507

External exposure likelihood

Halo Surface Signal score for CVE-2015-2546

This vulnerability resides within the Windows kernel-mode driver and requires a local user to execute a crafted application to exploit the flaw. As a local-privilege-elevation issue affecting OS internals, it lacks remote network reachability and is not exposed to the public internet.

Horizon Alert

Summary of the vulnerability and why it matters

The kernel-mode driver in Microsoft Windows operating systems is susceptible to a flaw that can allow local users to elevate their privileges. This vulnerability resides within the Win32k component and can be exploited through a crafted application. Such an exploit could lead to unauthorized privilege escalation on affected systems.

Vulnerable Windows kernel-mode driver
Memory corruption weakness
Local privilege escalation

Attack Path

How an attacker could exploit the issue

This vulnerability allows a local attacker to gain elevated privileges within a Windows system. The attack targets the kernel-mode driver, a core component of the operating system. By exploiting a memory corruption flaw through a specially crafted application, an attacker can potentially compromise the entire system.

Local access to a system.
Attacker runs crafted application.
Attacker gains system control.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in the Windows kernel-mode driver allows local users to elevate their privileges through a crafted application. Successful exploitation could lead to significant data loss, system compromise, and disruption of business operations. The risk is amplified by the potential for known ransomware campaigns to leverage this vulnerability.

Likely attacker skill level: Medium.
Required access or conditions: Local access and user interaction.
Business risk or urgency: High.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability could allow local users to gain elevated privileges on affected systems. The impact on an organization includes the risk of unauthorized access and control over systems, potentially affecting data integrity and business operations. This privilege escalation could be leveraged by attackers to further compromise the network.

Identify affected systems.
Reduce exposure or isolate risk.
Apply vendor fix, verify, and monitor.

Frequently asked questions

What is the function of the Microsoft Windows kernel-mode driver?

The Microsoft Windows kernel-mode driver is a fundamental component of the operating system responsible for direct communication with hardware and managing system resources. It acts as a bridge between software applications and the computer's hardware, executing in kernel mode as part of the operating system's executive. This driver type is crucial for core OS functionalities like I/O, memory, process, and security management.

What type of weakness does CVE-2015-2546 describe?

CVE-2015-2546 describes a memory corruption weakness, specifically a "Win32k Memory Corruption Elevation of Privilege Vulnerability." This falls under the CWE-119 category, which indicates an improper restriction of operations within the bounds of a memory buffer. This type of vulnerability can occur when a program does not handle memory operations correctly, potentially allowing for unauthorized code execution or privilege escalation.

How can CVE-2015-2546 be triggered and what is its scope?

This vulnerability is triggered when a local user runs a specially crafted application. The scope of the vulnerability is limited to local privilege escalation, meaning an attacker must have initial access to the system. The exploit targets the Windows kernel-mode driver (Win32k.sys) and allows an attacker to gain elevated privileges on the affected system.

What is the relevance of CVE-2015-2546 in the current threat landscape?

CVE-2015-2546 has been identified as being used in ransomware campaigns and is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild. This makes it a significant concern for organizations, as active exploitation suggests a higher likelihood of targeted attacks.

What are the recommended steps to address CVE-2015-2546?

The primary recommended action is to apply all available Windows updates provided by Microsoft, as these updates contain the necessary patches for this vulnerability. Organizations should prioritize applying these updates to mitigate the risk of exploitation.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.