CVE-2021-28547 is a privilege escalation vulnerability found in the Adobe Creative Cloud Desktop Application for macOS, specifically affecting version 5.3 and earlier. The root cause of this vulnerability is improper input validation (CWE-20) in the desktop component of the Creative Cloud application. This flaw allows a normal user to delete the Out-Of-Box Experience (OOBE) directory, which is a critical directory used during the initial setup and configuration of the software. By exploiting this vulnerability, an attacker with standard user privileges can manipulate the application to gain administrative-level permissions over any directory on the system. This effectively means that the attacker can escalate their privileges from a normal user to an administrator, enabling them to modify, delete, or control files and directories that should be restricted. The vulnerability does not require any known exploits in the wild at the time of reporting, and no patches or fixes were linked in the provided information. The vulnerability was reserved in March 2021 and publicly disclosed in September 2021. Since it affects the macOS version of Adobe Creative Cloud, it targets users who rely on this software for creative workflows, including graphic design, video editing, and other multimedia production tasks. The improper input validation allows unauthorized deletion of critical directories, which can lead to unauthorized access and control over system resources, potentially compromising system integrity and confidentiality.

For European organizations, the impact of this vulnerability can be significant, especially for those in creative industries, media, advertising, and any sectors relying heavily on Adobe Creative Cloud for their daily operations. Privilege escalation vulnerabilities can lead to unauthorized access to sensitive files, intellectual property theft, and potential disruption of business operations. Since the vulnerability allows an attacker to gain administrator-level permissions, it could be leveraged to install malware, create persistent backdoors, or manipulate system configurations, leading to broader network compromise. Organizations with macOS environments using Adobe Creative Cloud are at risk of insider threats or malware exploiting this vulnerability to escalate privileges. This could affect confidentiality by exposing sensitive creative content, integrity by allowing unauthorized modifications, and availability if critical system components are altered or deleted. Given the lack of known exploits in the wild, the immediate risk may be moderate, but the potential for exploitation remains, especially if attackers develop proof-of-concept code. The vulnerability also poses risks to managed service providers and creative agencies servicing European clients, as compromise could cascade to client environments.

1. Immediate mitigation should include restricting user permissions to the minimum necessary, ensuring that normal users do not have write access to critical directories related to Adobe Creative Cloud. 2. Monitor and audit file system changes, particularly deletions or modifications of the OOBE directory and other Adobe Creative Cloud related directories, to detect suspicious activity early. 3. Implement application whitelisting and endpoint protection solutions that can detect and block unauthorized privilege escalation attempts. 4. Until an official patch is released, consider isolating macOS systems running Adobe Creative Cloud from sensitive networks or limiting their network access to reduce the risk of lateral movement. 5. Educate users about the risks of running untrusted scripts or applications that could exploit this vulnerability. 6. Regularly check Adobe’s security advisories for updates or patches addressing this vulnerability and apply them promptly once available. 7. Employ macOS security features such as System Integrity Protection (SIP) and ensure they are enabled and properly configured to limit unauthorized modifications to system files and directories. 8. Use endpoint detection and response (EDR) tools capable of detecting privilege escalation behaviors specific to macOS environments.