CVE-2020-6789 in Monitor Wall
Summary
by MITRE
Loading a DLL through an Uncontrolled Search Path Element in the Bosch Monitor Wall installer up to and including version 10.00.0164 potentially allows an attacker to execute arbitrary code on a victim's system. A prerequisite is that the victim is tricked into placing a malicious DLL in the same directory where the installer is started from.
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Analysis
by VulDB Data Team • 04/05/2021
The vulnerability identified as CVE-2020-6789 represents a critical security flaw in the Bosch Monitor Wall installer software, specifically affecting versions up to and including 10.00.0164. This issue falls under the category of uncontrolled search path element, a well-documented weakness that has been classified under CWE-427 and CWE-428 within the CWE database. The vulnerability stems from the installer's improper handling of dynamic link library (DLL) loading mechanisms, creating a pathway for privilege escalation and arbitrary code execution. Attackers can exploit this weakness by manipulating the software's search path to load malicious code instead of legitimate system libraries.
The technical implementation of this vulnerability involves the installer's failure to properly validate or restrict the directories from which it loads DLL dependencies. When the Bosch Monitor Wall installer executes, it searches through specific directories in a predetermined order to locate required DLL files. The flaw occurs because the installer does not implement proper security controls to prevent loading of DLLs from untrusted locations, particularly those in the current working directory where the installer is executed. This behavior creates a race condition and path manipulation opportunity that adversaries can exploit through social engineering tactics.
The operational impact of CVE-2020-6789 extends beyond simple code execution, as it provides attackers with a potential foothold for further system compromise. The vulnerability aligns with ATT&CK technique T1059.001 for executing malicious code and T1547.001 for persistence mechanisms. Once an attacker successfully places a malicious DLL in the same directory as the installer, they can execute arbitrary commands with the privileges of the user running the installer. This presents a significant risk for enterprise environments where administrative privileges may be used to execute the installer, potentially leading to complete system compromise. The vulnerability is particularly concerning because it leverages the trust relationship between the installer and the user, requiring minimal technical expertise to exploit.
Mitigation strategies for this vulnerability must address both the immediate installer behavior and broader system security practices. Organizations should implement strict file permission controls and ensure that installation directories are not writable by unprivileged users. The recommended approach includes updating to the patched version of the Bosch Monitor Wall software, as vendors typically address such issues through proper DLL loading mechanisms and secure path resolution. Additionally, system administrators should implement application whitelisting policies that restrict execution of unauthorized DLLs and monitor for suspicious installation activities. The vulnerability demonstrates the importance of secure coding practices and the principle of least privilege in software development, particularly for installation utilities that operate with elevated privileges. Network segmentation and endpoint protection solutions can also provide additional layers of defense against exploitation attempts.