CVE-2019-1077 in Visual Studio
Summary
by MITRE
An elevation of privilege vulnerability exists when the Visual Studio updater service improperly handles file permissions, aka 'Visual Studio Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 07/09/2020
The CVE-2019-1077 vulnerability represents a critical elevation of privilege flaw within the Visual Studio updater service that exploits improper file permission handling mechanisms. This vulnerability specifically targets the Windows operating system environment where Visual Studio components are installed and maintained through automated update processes. The flaw manifests when the updater service fails to properly validate or enforce file permissions during the update cycle, creating opportunities for malicious actors to escalate their privileges from standard user level to administrative rights. The vulnerability exists within the service architecture that manages Visual Studio installations and updates, making it particularly dangerous as it directly impacts the integrity of development environments that are often considered trusted within corporate networks.
The technical implementation of this vulnerability stems from insufficient access control mechanisms within the Visual Studio updater service executable. When the service processes update files or modifies system components, it does not adequately verify the permissions of the files it operates on or the directories it accesses. This weakness allows an attacker to manipulate the update process by placing malicious files in locations where the updater service expects legitimate update components to reside. The flaw aligns with CWE-276, which describes improper file permissions, and specifically relates to inadequate access control validation during service operations. Attackers can exploit this by creating symbolic links or manipulating file paths to redirect the update service to execute malicious code with elevated privileges, effectively bypassing standard user restrictions.
The operational impact of CVE-2019-1077 extends beyond simple privilege escalation as it creates a persistent backdoor within development environments that are typically considered secure. Organizations using Visual Studio for software development are particularly vulnerable since these environments often contain sensitive source code, build configurations, and development credentials. The vulnerability enables attackers to maintain long-term access to systems while remaining undetected, as the malicious activities occur through legitimate update mechanisms. This makes the attack vector particularly stealthy and difficult to detect through conventional security monitoring approaches. The threat landscape for this vulnerability includes both insider threats and external attackers who seek to compromise development infrastructure, potentially gaining access to intellectual property, source code repositories, and sensitive application data.
Mitigation strategies for CVE-2019-1077 require immediate patch application from Microsoft as the primary defense mechanism, since the vulnerability exists within the core updater service functionality. Organizations should implement strict file permission controls on Visual Studio installation directories and update locations to prevent unauthorized modifications. The implementation of least privilege principles for Visual Studio services and the enforcement of secure file handling practices through group policy configurations can significantly reduce exploitation risk. Security teams should also monitor for unusual update activities and file modifications in Visual Studio related directories, as these may indicate attempted exploitation. Additionally, network segmentation and application whitelisting can help prevent malicious code execution even if privilege escalation occurs, aligning with ATT&CK technique T1068 which covers local privilege escalation through service manipulation. Regular security assessments of development environments and implementation of automated vulnerability scanning tools specifically targeting Visual Studio components should be part of comprehensive security postures to prevent exploitation of this and similar vulnerabilities.