CVE-2018-4048 in Galaxy
Summary
by MITRE
An exploitable local privilege elevation vulnerability exists in the file system permissions of the `Temp` directory in GOG Galaxy 1.2.48.36 (Windows 64-bit Installer). An attacker can overwrite executables of the Desktop Galaxy Updater to exploit this vulnerability and execute arbitrary code with SYSTEM privileges.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 09/25/2023
This vulnerability represents a critical local privilege escalation flaw in GOG Galaxy's desktop updater component that operates with elevated SYSTEM privileges. The issue stems from inadequate file system permissions within the application's temporary directory structure, creating a path traversal and overwrite opportunity that allows attackers to execute arbitrary code with the highest available privileges. The vulnerability specifically affects the Windows 64-bit installer version 1.2.48.36 of GOG Galaxy, where the Desktop Galaxy Updater component runs with SYSTEM-level permissions, making it an attractive target for privilege escalation attacks. The flaw exists because the application's temporary directory lacks proper access controls that would prevent unauthorized modification of executable files, creating a persistent backdoor mechanism for attackers to gain elevated system access.
The technical implementation of this vulnerability involves the exploitation of weak file system permissions in the Temp directory where the Desktop Galaxy Updater stores temporary files. When the updater runs with SYSTEM privileges, any attacker who can write to the Temp directory can replace legitimate executables with malicious payloads. This creates a classic privilege escalation vector where a low-privileged user can manipulate the updater's execution flow by overwriting binaries in the temporary storage location. The vulnerability operates through a combination of path traversal and file overwrite techniques that bypass standard Windows security mechanisms, allowing attackers to execute code with SYSTEM privileges. The flaw demonstrates poor security by design principles, where the application assumes that temporary directories are secure without implementing proper access control measures.
The operational impact of this vulnerability is severe as it provides attackers with complete system compromise capabilities through a relatively simple exploitation technique. Once an attacker gains access to the Temp directory, they can overwrite the Desktop Galaxy Updater executable with a malicious version that will execute with SYSTEM privileges upon the next update cycle or system reboot. This creates a persistent threat that can survive system restarts and provides attackers with complete control over the affected system. The vulnerability is particularly dangerous because it leverages legitimate application components to execute malicious code, making detection more difficult and allowing attackers to maintain long-term access to the compromised system. The exploitation process requires minimal privileges initially but results in full system compromise, making it an attractive target for both casual attackers and sophisticated threat actors.
Mitigation strategies should focus on implementing proper file system permissions and access controls for temporary directories used by privileged applications. The recommended approach involves configuring the Temp directory with restrictive permissions that prevent unauthorized users from writing to or modifying executable files. Security best practices dictate that temporary directories should be isolated from user access and should not allow modification of executable content by non-privileged users. Additionally, applications should implement proper code signing verification for all executables in temporary directories to prevent unauthorized replacement of legitimate binaries. The vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a typical ATT&CK technique under privilege escalation tactics where adversaries leverage weak file permissions to gain elevated system access. Organizations should also implement application whitelisting policies and monitor for suspicious file modification activities in system directories to detect potential exploitation attempts.