CVE-2019-1449 in Office
Summary
by MITRE
A security feature bypass vulnerability exists in the way that Office Click-to-Run (C2R) components handle a specially crafted file, which could lead to a standard user, any AppContainer sandbox, and Office LPAC Protected View to escalate privileges to SYSTEM.To exploit this bug, an attacker would have to run a specially crafted file, aka 'Microsoft Office ClickToRun Security Feature Bypass Vulnerability'.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/13/2024
This vulnerability represents a critical security flaw in Microsoft Office Click-to-Run components that enables privilege escalation from standard user level to SYSTEM privileges. The issue stems from how C2R handles specially crafted files, creating a security feature bypass that undermines the intended sandboxing mechanisms. The vulnerability specifically affects the Office Click-to-Run service architecture that delivers and manages Office applications, making it particularly dangerous as it targets the core installation and execution framework of Microsoft Office products.
The technical implementation of this flaw involves manipulation of the Click-to-Run service's security model, which is designed to prevent unauthorized code execution and privilege elevation. When a malicious file is processed through the C2R component, it exploits a weakness in the service's validation mechanisms, allowing code to bypass the standard AppContainer sandbox protections. This bypass affects multiple security layers including the Office LPAC Protected View environment, which is specifically designed to isolate potentially dangerous content. The vulnerability operates at the kernel level within the Windows operating system, leveraging the underlying Windows security architecture to escalate privileges without requiring administrative access.
The operational impact of this vulnerability is severe as it allows attackers to gain SYSTEM-level access with minimal user interaction requirements. An attacker needs only to execute a specially crafted file that triggers the vulnerability, making it particularly dangerous in phishing scenarios or when users inadvertently open malicious documents. The exploitation chain typically involves delivering a malicious file that, when processed by the Click-to-Run service, triggers the privilege escalation mechanism. This vulnerability affects all versions of Office that utilize the Click-to-Run installation technology, including Office 2016, Office 2019, and Office 365, making it widespread across enterprise environments.
Organizations should implement immediate mitigations including applying Microsoft security patches, disabling Click-to-Run functionality where possible, and implementing strict file execution policies. The vulnerability aligns with CWE-284 Access Control and ATT&CK technique T1068 Privilege Escalation, representing a sophisticated attack vector that combines multiple exploitation techniques. Security teams should monitor for suspicious file execution patterns and implement endpoint detection and response solutions that can identify anomalous behavior related to Click-to-Run service interactions. Additionally, network segmentation and application whitelisting can help prevent exploitation by limiting the attack surface and reducing the potential impact of successful exploitation attempts.