CVE-2019-0835 in Internet Explorer
Summary
by MITRE
An information disclosure vulnerability exists when the scripting engine does not properly handle objects in memory, aka 'Microsoft Scripting Engine Information Disclosure Vulnerability'.
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Analysis
by VulDB Data Team • 05/28/2020
The vulnerability identified as CVE-2019-0835 represents a critical information disclosure flaw within Microsoft's scripting engine that affects multiple Windows operating systems. This vulnerability resides in the way the scripting engine processes and manages objects within memory, creating potential pathways for unauthorized information exposure. The issue specifically impacts the Windows Scripting Host environment and can be exploited through malicious scripts or web content that triggers improper memory handling behaviors. Security researchers have classified this as a memory corruption vulnerability that stems from inadequate object management within the scripting engine's memory allocation and deallocation processes.
The technical root cause of CVE-2019-0835 lies in the scripting engine's failure to properly validate or handle memory objects during execution cycles. When malicious scripts attempt to manipulate objects in memory, the engine does not adequately sanitize or secure these operations, leading to potential information leakage through memory corruption or improper object handling. This vulnerability typically manifests when scripts interact with COM objects or other memory-resident components, where the engine's memory management routines fail to prevent unauthorized access to sensitive data structures. The flaw operates at the intersection of memory management and object lifecycle handling, creating opportunities for attackers to extract information that should remain protected within the scripting engine's memory space. According to CWE classification, this vulnerability maps to CWE-200: Information Exposure, with specific characteristics aligned to improper handling of memory objects and insufficient validation of object states during execution.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable more sophisticated attacks when combined with other exploitation techniques. An attacker who successfully exploits CVE-2019-0835 can potentially extract sensitive data from memory, including credentials, application data, or system information that could be leveraged for further compromise. The vulnerability is particularly concerning because it can be triggered through various attack vectors including malicious websites, email attachments, or compromised applications that utilize scripting components. When exploited in browser contexts, this vulnerability can lead to complete system compromise, as the information disclosure can reveal critical system components or application state that attackers can use to craft more targeted attacks. The vulnerability's impact is amplified in enterprise environments where scripting engines are frequently used for automation and administrative tasks, potentially exposing sensitive organizational data through memory leaks.
Mitigation strategies for CVE-2019-0835 focus on both immediate patching and operational security measures. Microsoft released security updates that address the vulnerability through enhanced memory management routines and improved object validation within the scripting engine. Organizations should prioritize applying the relevant security patches as soon as possible, particularly those affecting Windows 7, Windows 8.1, Windows Server 2008 R2, and Windows Server 2012 R2 systems. Beyond patching, security teams should implement additional protective measures including restricting scripting engine usage, implementing application whitelisting policies, and monitoring for suspicious scripting activity. Network segmentation and firewall rules can help limit the potential attack surface for this vulnerability. Security professionals should also consider implementing behavioral monitoring solutions that can detect anomalous memory access patterns or object manipulation that may indicate exploitation attempts. The vulnerability's characteristics align with ATT&CK technique T1059.007: Command and Scripting Interpreter: Windows Command Shell, as attackers may leverage scripting engines to execute malicious code that exploits this information disclosure vulnerability. Regular security assessments and vulnerability scanning should include checks for proper patch management and implementation of the recommended mitigations to ensure comprehensive protection against this and similar scripting engine vulnerabilities.