CVE-2020-7873 in ActiveX Control
Summary
by MITRE • 09/09/2021
Download of code without integrity check vulnerability in ActiveX control of Younglimwon Co., Ltd allows the attacker to cause a arbitrary file download and execution.
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Analysis
by VulDB Data Team • 09/12/2021
The vulnerability identified as CVE-2020-7873 represents a critical security flaw within the ActiveX control developed by Younglimwon Co., Ltd, which exposes systems to arbitrary code execution through insecure download mechanisms. This vulnerability specifically affects the ActiveX control's implementation of code downloading functionality, where the system fails to perform proper integrity verification before executing downloaded components. The flaw stems from the absence of cryptographic checksum validation or digital signature verification, allowing attackers to manipulate or replace downloaded files with malicious payloads without detection.
The technical implementation of this vulnerability resides in the ActiveX control's trust model, which assumes that downloaded code is legitimate without performing validation checks. According to CWE-494, this represents a dangerous pattern of accepting unverified code downloads, where the control downloads files from remote locations without implementing proper integrity verification mechanisms. The vulnerability creates an attack surface where malicious actors can substitute legitimate files with malicious counterparts, leveraging the trust relationship established by the ActiveX control to execute arbitrary code on vulnerable systems. This flaw operates at the intersection of CWE-502, which addresses unsafe deserialization, and CWE-22, concerning unsafe handling of file paths, as the control's download mechanism does not properly validate or sanitize the downloaded content.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to perform complete system compromise through the ActiveX control's download functionality. Attackers can leverage this vulnerability to download malware, backdoors, or other malicious payloads that will execute with the privileges of the user running the vulnerable ActiveX control. The attack vector typically involves hosting malicious files on compromised servers or through man-in-the-middle attacks, where the ActiveX control downloads these files without verifying their integrity. This vulnerability is particularly dangerous in enterprise environments where ActiveX controls are often deployed with elevated privileges, potentially allowing attackers to gain system-level access or escalate privileges within the network.
Mitigation strategies for CVE-2020-7873 require immediate remediation through patching the affected ActiveX control, as the vulnerability cannot be effectively addressed through configuration changes alone. Organizations should implement strict network segmentation to limit access to systems containing vulnerable ActiveX controls, while also disabling ActiveX controls in browsers where possible. The implementation of application whitelisting policies can help prevent execution of unauthorized code downloads, though this approach requires careful maintenance of trusted application lists. According to ATT&CK technique T1195, which covers content injection attacks, organizations should monitor for suspicious download activities and implement network-based detection mechanisms to identify potential exploitation attempts. Additionally, regular security assessments should verify that no legacy ActiveX controls remain in use, as these components often pose persistent security risks that are difficult to remediate without complete removal from systems.