CVE-2020-0737 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in the way that the tapisrv.dll handles objects in memory, aka 'Windows Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0739.
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Analysis
by VulDB Data Team • 03/30/2024
The vulnerability identified as CVE-2020-0737 represents a critical elevation of privilege flaw within the Windows operating system's tapisrv.dll component. This issue stems from improper handling of memory objects within the TAPI (Telephony Application Programming Interface) service, which is responsible for managing telephony functions and communications within Windows environments. The vulnerability specifically affects how the system processes and manages memory structures associated with telephony operations, creating a pathway for malicious actors to escalate their privileges from standard user level to system level access. The flaw exists in the Windows Telephony Service implementation and impacts multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern across enterprise and consumer deployments.
The technical root cause of this vulnerability lies in the insufficient validation and memory management practices within the tapisrv.dll module. When the system processes certain telephony-related objects or requests, the memory handling routines fail to properly validate input parameters or enforce proper access controls. This memory management deficiency allows attackers to manipulate the way objects are stored and accessed in memory, potentially leading to arbitrary code execution and privilege escalation. The vulnerability is categorized under CWE-125, which describes "Out-of-bounds Read" conditions, and more specifically relates to improper handling of memory objects during telephony service operations. The flaw enables attackers to exploit memory corruption patterns that can be leveraged to execute malicious code with elevated privileges, effectively bypassing standard Windows security controls and user access restrictions.
The operational impact of CVE-2020-0737 is severe and potentially devastating for affected organizations. Attackers who successfully exploit this vulnerability can gain system-level privileges, enabling them to install malware, modify system files, access sensitive data, and establish persistent backdoors within the compromised system. The vulnerability's exploitation requires minimal user interaction since it can be triggered through legitimate telephony service operations, making it particularly dangerous in enterprise environments where telephony services are commonly used. This flaw directly maps to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation," and represents a significant vector for attackers seeking to establish persistent access within networks. Organizations running affected Windows versions face the risk of complete system compromise, with potential cascading effects across networked environments where attackers can leverage the elevated privileges to move laterally and access additional systems.
Mitigation strategies for CVE-2020-0737 should prioritize immediate patch deployment through Microsoft's regular security updates, as the vendor has released patches addressing this specific vulnerability. Organizations should also implement network segmentation and access control measures to limit telephony service exposure, particularly disabling unnecessary telephony services when not required. Security monitoring should focus on detecting unusual privilege escalation attempts and anomalous memory access patterns within telephony service processes. The vulnerability demonstrates the importance of proper memory management practices in system services and highlights the need for comprehensive code review processes, particularly for components handling user input or external communications. System administrators should also consider implementing application whitelisting policies to restrict execution of unauthorized code, and maintain regular security assessments to identify potential exploitation vectors within telephony and communication services. Additionally, organizations should review their incident response procedures to ensure rapid detection and containment of privilege escalation attempts that may leverage this vulnerability.