External risk intelligence

Windows CSRSS Privilege Escalation Vulnerability.

CVE advisoryKnown Exploit

CVE-2022-22047

A privilege escalation vulnerability in the Windows Client Server Run-time Subsystem allows local attackers to gain elevated privileges. This could lead to unauthorized access to sensitive data and system control, posing a business risk to affected organizations. Updates are recommended to address this.

1Halo Surface Signal

Microsoft Windows 10 1507

before 10.0.10240.19360before 10.0.14393.5246before 10.0.17763.3165before 10.0.19042.1826before 10.0.19043.1826before 10.0.19044.1826before 10.0.22000.795r2before 10.0.20348.825

External exposure likelihood

Halo Surface Signal score for CVE-2022-22047

This vulnerability resides within the Windows Client/Server Run-time Subsystem (CSRSS), a core local OS component. Exploitation requires local access to the system, making it inherently local-only and not reachable via the public internet.

Horizon Alert

Summary of the vulnerability and why it matters

The Windows Client Server Run-time Subsystem (CSRSS) is affected by a privilege escalation vulnerability. This flaw allows an attacker with local access to elevate their privileges on the affected system. The potential impact includes unauthorized access to sensitive data and system control.

Vulnerable: Windows Client Server Run-time Subsystem (CSRSS)
Weakness: Privilege escalation
Impact: Unauthorized system access and data exposure

Attack Path

How an attacker could exploit the issue

This vulnerability affects the Windows Client Server Run-time Subsystem (CSRSS). An attacker with local access to a system could exploit this flaw to gain elevated privileges. Successful exploitation could allow an attacker to run malicious code with SYSTEM privileges, potentially leading to a compromise of the affected system. This could impact the confidentiality, integrity, and availability of data and systems.

Local system access is required.
Attacker triggers the vulnerability.
Attacker gains SYSTEM privileges.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability impacts the Windows Client Server Runtime Subsystem (CSRSS), a critical component within the operating system. Exploitation allows an attacker with existing local access to elevate their privileges to SYSTEM level. This could lead to the compromise of sensitive data and the disruption of business operations. Given the potential for significant damage and the internal nature of the attack vector, organizations should prioritize addressing this vulnerability.

Attacker skill level: Standard.
Required access: Local system access.
Business risk: High.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the Windows Client Server Run-time Subsystem could allow an attacker to gain elevated privileges. Organizations should prioritize identifying all systems that may be affected by this vulnerability. Addressing this risk involves limiting exposure, applying the vendor's provided security updates, and confirming the successful implementation of these fixes. Ongoing monitoring is also recommended to detect any related malicious activity.

Locate all exposed assets.
Reduce exposure or isolate risk.
Fix, verify, and monitor.

Frequently asked questions

What is the Windows Client Server Run-time Subsystem (CSRSS) privilege escalation vulnerability?

This vulnerability affects the Windows Client Server Run-time Subsystem (CSRSS), a core component of the Windows operating system. It allows an attacker who already has local access to a system to elevate their privileges to the highest level, known as SYSTEM privileges. This could enable them to run malicious code, access sensitive data, and potentially take full control of the affected machine. The weakness is categorized as CWE-426, which refers to untrusted search path execution, indicating a potential...

How can the Windows CSRSS privilege escalation vulnerability be exploited, and what is the weakness class?

The weakness in this vulnerability is classified as CWE-426, indicating an issue with untrusted search path execution. Exploitation requires an attacker to have initial local access to the target system. Once local access is achieved, the attacker can trigger the vulnerability, which allows them to escalate their privileges to SYSTEM level. This means they can execute commands and access resources as if they were the operating system's administrator, bypassing normal user restrictions.

What is the trigger path and scope of the Windows CSRSS privilege escalation vulnerability?

The trigger path for this vulnerability involves an attacker with local access to the system. While the specific technical steps to trigger the flaw are not detailed, the outcome is a privilege escalation to SYSTEM. The scope of the vulnerability is local, meaning it cannot be exploited remotely over a network. An attacker must first gain a foothold on the machine to exploit this weakness.

What is the relevance of the Windows CSRSS privilege escalation vulnerability, and why is it important for organizations to address?

This vulnerability is relevant because it allows for privilege escalation to SYSTEM, a critical security concern. While it requires local access, a compromised user account or a machine already under an attacker's control could be leveraged. The potential impact includes unauthorized access to sensitive data, system disruption, and the ability to further compromise the environment. Organizations should prioritize addressing this to prevent potential security breaches and maintain system integrity.

What practical steps should organizations take to respond to the Windows CSRSS privilege escalation vulnerability?

Organizations should focus on identifying all systems affected by this vulnerability. The primary response is to apply security updates provided by Microsoft, as this vulnerability is addressed through patches. It is crucial to verify that these updates have been successfully implemented across all relevant systems. Limiting exposure by restricting local access where possible and implementing ongoing monitoring for suspicious activity related to privilege escalation are also recommended practices.

References

Cyber Threat Intelligence (CTI)

Sources: threatActor

Written by Nicholas Merritt

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