CVE-2025-21360 in AutoUpdate
Summary
by MITRE • 01/14/2025
Microsoft AutoUpdate (MAU) Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 05/08/2026
Microsoft AutoUpdate represents a critical elevation of privilege vulnerability that exploits weaknesses in the software update mechanism of macOS systems. This vulnerability allows attackers to escalate their privileges from standard user level to administrator level through manipulation of the update process. The flaw resides in how MAU handles privilege escalation during the installation of updates, particularly when the system attempts to execute update components with elevated permissions. Attackers can leverage this vulnerability by crafting malicious update packages or manipulating the update download process to execute arbitrary code with system-level privileges. The vulnerability impacts all versions of macOS that utilize Microsoft AutoUpdate for managing Microsoft application updates including Office for Mac, which creates a significant attack surface for threat actors seeking persistent access to affected systems.
The technical exploitation of this vulnerability involves a combination of privilege escalation techniques that align with CWE-269 Improper Privilege Management and CWE-787 Out-of-bounds Write patterns commonly found in update mechanisms. Attackers typically begin by gaining initial access through phishing campaigns or other initial compromise vectors before utilizing the MAU vulnerability to elevate their privileges. The flaw manifests when MAU fails to properly validate update packages or when it executes update components without sufficient privilege checks. This vulnerability specifically relates to improper handling of file permissions and execution contexts within the update framework, creating opportunities for attackers to inject malicious code that executes with administrator privileges. The exploitation process often involves creating malicious update payloads that appear legitimate to the update mechanism but contain malicious code designed to establish persistence or exfiltrate data.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise capabilities. Once an attacker achieves administrator privileges through this vulnerability, they can modify system files, install backdoors, disable security controls, and establish persistent access to the compromised system. The vulnerability also affects the integrity of the update process itself, potentially allowing attackers to bypass security measures that rely on trusted update channels. This creates a particularly dangerous scenario where malicious updates can appear legitimate to the system while simultaneously compromising system security. Organizations using Microsoft AutoUpdate are at risk of complete system compromise, with potential for data exfiltration, lateral movement, and establishment of command and control infrastructure. The vulnerability's impact is amplified when combined with other attack vectors, as attackers can use the elevated privileges to bypass endpoint protection mechanisms and security monitoring systems.
Mitigation strategies for this vulnerability must address both immediate patching requirements and broader security posture improvements. Microsoft has released security updates to address this vulnerability, and organizations should prioritize deployment of these patches across all affected systems. System administrators should implement additional controls including monitoring for unusual update activities, restricting network access to update servers, and implementing application control policies to prevent execution of unauthorized update components. The mitigation approach should align with ATT&CK technique T1068 Privilege Escalation and T1547 Application Shimming to ensure comprehensive protection against exploitation attempts. Organizations should also consider implementing network segmentation to limit access to update servers and monitor for suspicious update package downloads. Regular security assessments and vulnerability scanning should be conducted to identify systems that may be running outdated versions of MAU or Microsoft applications that are vulnerable to this exploitation technique. Additionally, user education programs should be implemented to reduce the risk of initial compromise through social engineering attacks that could lead to exploitation of this privilege escalation vulnerability.