CVE-2017-7084 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13 is affected. The issue involves the "Application Firewall" component. It allows remote attackers to bypass intended settings in opportunistic circumstances by leveraging incorrect handling of a denied setting after an upgrade.
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Analysis
by VulDB Data Team • 01/20/2021
The vulnerability identified as CVE-2017-7084 resides within Apple's macOS operating system affecting versions prior to 10.13. This security flaw specifically targets the Application Firewall component which serves as a crucial network security mechanism designed to control incoming connections to applications. The issue manifests as a privilege escalation vulnerability that occurs during system upgrade scenarios, creating a window of opportunity for malicious actors to exploit the system's security controls.
The technical root cause of this vulnerability stems from improper state management within the Application Firewall implementation. When macOS undergoes an upgrade process, the firewall configuration fails to properly handle denied settings that were previously established. This creates a race condition where the firewall's state becomes inconsistent, allowing unauthorized network access that should have been blocked. The flaw operates under the weakness category of CWE-284, which specifically addresses improper access control mechanisms, and represents a failure in maintaining security boundaries during system transitions.
The operational impact of CVE-2017-7084 extends beyond simple network access bypass, as it provides attackers with opportunities to establish persistent access points within compromised systems. During upgrade scenarios, the firewall's denial settings become ineffective, potentially allowing remote attackers to connect to services that should be restricted. This vulnerability aligns with ATT&CK technique T1068 which involves exploiting local privileges to escalate access, and T1071.004 which covers application layer protocol usage. The opportunistic nature of the exploit means that attackers need only wait for system upgrades to occur, making this vulnerability particularly dangerous in enterprise environments where patch management schedules may be predictable.
Security researchers have noted that the vulnerability's exploitation requires minimal privileges and can be automated, making it attractive to threat actors seeking to establish backdoors or exfiltrate data. The risk is elevated in environments where macOS systems are frequently upgraded, as the window of vulnerability increases with each upgrade cycle. Organizations should consider implementing network monitoring to detect unusual connection patterns that may indicate exploitation attempts. The flaw demonstrates the critical importance of maintaining consistent security controls throughout system lifecycle events, particularly during upgrade processes where configuration states may become inconsistent. Remediation requires immediate deployment of macOS 10.13 or later versions, which contain corrected firewall handling mechanisms that properly maintain access control settings across upgrade scenarios.