CVE-2019-1037 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in the way Windows Error Reporting (WER) handles files, aka 'Windows Error Reporting Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 07/02/2020
The Windows Error Reporting Elevation of Privilege Vulnerability represents a critical security flaw in Microsoft Windows operating systems that allows attackers to escalate their privileges from standard user level to administrative rights. This vulnerability specifically resides within the Windows Error Reporting component which is responsible for collecting and processing crash information from applications and system processes. The flaw stems from improper handling of file operations within the WER subsystem, creating an exploitable condition that adversaries can leverage to execute malicious code with elevated privileges. The vulnerability affects multiple Windows versions including Windows 7, Windows 8.1, Windows 10, and Windows Server 2008 R2, making it a widespread concern across enterprise environments. According to CWE-264, this vulnerability falls under the category of "Permissions, Privileges, and Access Controls" where inadequate access control mechanisms allow unauthorized privilege escalation. The attack surface is particularly concerning as WER is a legitimate system component that runs with elevated privileges, making it an attractive target for attackers seeking persistent access to systems.
The technical exploitation of this vulnerability occurs through manipulation of error reporting files that are processed by the WER service. Attackers can craft malicious files that, when processed by WER, trigger a code execution path that bypasses normal privilege checks. The flaw typically involves improper validation of file paths or symbolic link manipulation during the error reporting process, allowing attackers to redirect execution flow to malicious payloads. This type of vulnerability aligns with ATT&CK technique T1068 which describes "Local Port/Service Discovery" and T1059 which covers "Command and Scripting Interpreter" as attackers often leverage such privileges to establish persistent access. The vulnerability specifically relates to improper handling of file operations in the Windows Error Reporting service, where insufficient sandboxing or privilege separation allows unprivileged users to influence the processing of error reports. The system's failure to properly validate file access permissions during error reporting creates a path for privilege escalation attacks that can ultimately result in full system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation, as successful exploitation can lead to complete system compromise and persistent access for attackers. Once an attacker gains administrative privileges through this vulnerability, they can install rootkits, modify system files, establish backdoors, and exfiltrate sensitive data from the compromised system. The vulnerability's presence in WER makes it particularly dangerous because this component is designed to run with elevated privileges and is often enabled by default in Windows installations. Organizations may experience significant operational disruption if this vulnerability is exploited, as attackers can use the elevated privileges to move laterally within networks, escalate to other systems, and maintain persistent access. The vulnerability's impact is compounded by the fact that WER processes error reports automatically without user intervention, meaning that exploitation can occur without any user interaction or awareness. This makes the vulnerability particularly challenging to detect and remediate in enterprise environments where automated error reporting is common.
Mitigation strategies for this vulnerability should focus on immediate patch application and system hardening measures. Microsoft released security updates that address the privilege escalation flaw by correcting file handling procedures within the Windows Error Reporting service. Organizations should prioritize deployment of the relevant security patches and updates as soon as they become available. Additionally, system administrators should implement discretionary access control measures to limit WER's file access permissions and consider disabling WER in environments where it is not essential for troubleshooting. Network segmentation and monitoring solutions should be employed to detect suspicious file operations or unauthorized privilege escalation attempts. The implementation of application whitelisting policies and enhanced monitoring of WER-related processes can help detect exploitation attempts before they succeed. According to security best practices and the principle of least privilege, organizations should regularly review and audit WER configurations to ensure that it operates with minimal required permissions. Security teams should also consider implementing behavioral monitoring solutions that can detect anomalous file access patterns consistent with the exploitation of this vulnerability, particularly around error reporting directories and temporary file locations where malicious payloads might be staged.