CVE-2020-0773 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists when the Windows ActiveX Installer Service improperly handles memory.To exploit this vulnerability, an attacker would first have to gain execution on the victim system, aka 'Windows ActiveX Installer Service Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0770, CVE-2020-0860.
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Analysis
by VulDB Data Team • 04/10/2024
The vulnerability described in CVE-2020-0773 represents a critical elevation of privilege flaw within the Windows ActiveX Installer Service component. This service is responsible for processing and installing ActiveX controls on Windows systems, making it a potential attack vector for malicious actors seeking to escalate their privileges. The vulnerability stems from improper memory handling within the service, which creates exploitable conditions that can be leveraged by attackers who have already achieved initial system access. The Windows ActiveX Installer Service operates with elevated privileges, making any memory handling flaws particularly dangerous as they can be exploited to gain higher-level system access than originally intended.
The technical flaw manifests in how the ActiveX Installer Service manages memory allocation and deallocation during the processing of ActiveX components. When the service encounters malformed or specially crafted ActiveX installations, it fails to properly validate memory operations, potentially leading to memory corruption conditions. This memory handling deficiency creates opportunities for attackers to manipulate the service's behavior through carefully constructed input data that triggers buffer overflows, use-after-free conditions, or other memory corruption vulnerabilities. The improper memory handling could involve insufficient bounds checking during ActiveX control processing, inadequate validation of input parameters, or failure to properly manage memory pointers during installation operations.
From an operational perspective, exploitation of this vulnerability requires an attacker to first establish a foothold on the target system through other means, as the vulnerability itself cannot be exploited remotely without prior access. Once an attacker has execution privileges, they can leverage this memory handling flaw to execute arbitrary code with elevated privileges typically associated with system-level processes. The impact extends beyond simple privilege escalation as successful exploitation could enable attackers to install persistent backdoors, modify system files, access sensitive data, or establish command and control channels. This vulnerability particularly affects enterprise environments where ActiveX controls are commonly used for legacy applications, making it a significant concern for organizations with older Windows deployments.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read scenarios. Additionally, the exploitation pattern corresponds to techniques documented in the ATT&CK framework under T1068, which covers 'Local Privilege Escalation' and T1059, covering 'Command and Scripting Interpreter' as attackers may use the elevated privileges to execute further malicious commands. Organizations should implement immediate mitigations including applying Microsoft security patches, disabling unnecessary ActiveX controls, and implementing application whitelisting policies. Network segmentation and monitoring for suspicious ActiveX installation activities can also help detect potential exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date system patches and conducting regular security assessments of legacy components that may contain memory handling vulnerabilities.