CVE-2020-15009 in ScreenPad2_Upgrade_Tool.msi
Summary
by MITRE
AsusScreenXpertServicec.exe and ScreenXpertUpgradeServiceManager.exe in ScreenPad2_Upgrade_Tool.msi V1.0.3 for ASUS PCs with ScreenPad 1.0 (UX450FDX, UX550GDX and UX550GEX) could lead to unsigned code execution with no additional restrictions when a user puts an application at a particular path with a particular file name.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/05/2020
The vulnerability identified as CVE-2020-15009 resides within the ScreenPad2_Upgrade_Tool.msi package version 1.0.3 distributed by ASUS for specific laptop models including UX450FDX, UX550GDX, and UX550GEX. This flaw manifests in two primary executable components: AsusScreenXpertServicec.exe and ScreenXpertUpgradeServiceManager.exe which together form part of the ScreenPad 1.0 upgrade mechanism. The vulnerability represents a critical code execution flaw that allows adversaries to bypass security restrictions through a specific file placement attack vector.
The technical implementation of this vulnerability stems from insufficient input validation and improper privilege escalation handling within the upgrade service components. When a user places a malicious application at a predetermined path with a specific filename, the vulnerable service executes this code without proper verification or code signing checks. This behavior directly violates the principle of least privilege and creates an attack surface where untrusted code can be executed with elevated privileges. The flaw essentially allows for privilege escalation from standard user context to system-level execution, making it particularly dangerous in enterprise environments where users may not have administrative rights.
The operational impact of this vulnerability extends beyond simple code execution, as it provides a persistent attack vector that can be leveraged for various malicious activities including privilege escalation, data exfiltration, and system compromise. The attack requires only that a user place a specially crafted file in a specific location, making it relatively easy to exploit in targeted attacks. This vulnerability is particularly concerning because it operates without additional restrictions, meaning that once the file is placed correctly, the malicious code executes automatically without user interaction or additional authentication requirements. The implications for user security are significant, as this vulnerability could allow attackers to establish persistent backdoors or deploy additional malware payloads.
Mitigation strategies for CVE-2020-15009 should focus on immediate remediation through ASUS firmware updates and service pack releases. System administrators should implement strict file system access controls and monitor for unauthorized file placement in the affected paths. The vulnerability aligns with CWE-787 (Out-of-bounds Write) and CWE-20 (Improper Input Validation) categories, representing a classic case of insecure file handling that allows arbitrary code execution. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1068 (Local Privilege Escalation) techniques, as it enables both code execution and privilege elevation. Organizations should also consider implementing application whitelisting policies to prevent execution of unsigned binaries in critical system directories, and conduct regular security audits to identify and remediate similar vulnerabilities in other system components.