CVE-2019-0791 in Windows
Summary
by MITRE
A remote code execution vulnerability exists when the Microsoft XML Core Services MSXML parser processes user input, aka 'MS XML Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2019-0790, CVE-2019-0792, CVE-2019-0793, CVE-2019-0795.
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Analysis
by VulDB Data Team • 07/11/2024
The vulnerability described in CVE-2019-0791 represents a critical remote code execution flaw within Microsoft XML Core Services MSXML parser, specifically affecting versions of the software that process user input through the XML parsing engine. This vulnerability allows attackers to execute arbitrary code on affected systems remotely without requiring authentication, making it particularly dangerous in enterprise environments where XML processing is commonly employed. The flaw resides in how the MSXML parser handles malformed XML input, creating opportunities for malicious actors to inject and execute malicious payloads through carefully crafted XML documents or web requests. This vulnerability impacts a wide range of Microsoft products including Windows operating systems, Office applications, and various server platforms that utilize MSXML for XML processing operations.
The technical implementation of this vulnerability stems from improper input validation within the MSXML parser component, which fails to properly sanitize or validate user-supplied XML data before processing. When the parser encounters specially crafted XML content containing malicious elements or embedded scripts, it can trigger unintended code execution paths within the application memory space. This behavior aligns with CWE-129, which describes improper validation of length of input buffers, and CWE-74, which addresses injection flaws during web requests to a web application. The vulnerability typically manifests when XML documents contain malformed elements, unexpected character sequences, or embedded payloads that exploit memory corruption issues within the parser's processing logic. Attackers can leverage this weakness by delivering malicious XML content through various attack vectors including web browsers, email attachments, or web services that process XML data.
The operational impact of CVE-2019-0791 extends far beyond simple code execution, as it provides attackers with persistent access to compromised systems and enables further exploitation within network environments. Once successfully exploited, the vulnerability allows threat actors to establish command and control capabilities, escalate privileges, and potentially move laterally across networks. This vulnerability particularly affects organizations that rely heavily on XML-based web services, document processing, or applications that parse external XML content from untrusted sources. The attack surface includes web applications, email systems, and any service that processes XML data from external parties, making it a prime target for advanced persistent threats and zero-day exploitation campaigns. Organizations may experience data breaches, system compromise, and potential full network infiltration when this vulnerability remains unpatched, with potential for widespread impact across multiple systems and applications.
Mitigation strategies for CVE-2019-0791 should prioritize immediate patch deployment from Microsoft as the primary defense mechanism, ensuring all affected systems receive the relevant security updates. Organizations should implement network segmentation and firewall rules to restrict access to XML processing services, particularly those exposed to external traffic. Input validation controls should be strengthened at all levels of application processing, including implementing XML schema validation and sanitization measures. Security monitoring should be enhanced to detect unusual XML processing patterns or attempts to exploit the vulnerability through web application firewalls and intrusion detection systems. Additionally, organizations should conduct thorough vulnerability assessments to identify all systems utilizing MSXML components and ensure proper patch management procedures are in place. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1071 for application layer protocol, highlighting the need for comprehensive network monitoring and endpoint protection measures to detect and prevent exploitation attempts.