CVE-2011-0639 in Mac OS X
Summary
by MITRE
Apple Mac OS X does not properly warn the user before enabling additional Human Interface Device (HID) functionality over USB, which allows user-assisted attackers to execute arbitrary programs via crafted USB data, as demonstrated by keyboard and mouse data sent by malware on a smartphone that the user connected to the computer.
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Analysis
by VulDB Data Team • 01/08/2018
The vulnerability identified as CVE-2011-0639 represents a significant security flaw in Apple Mac OS X operating systems that fundamentally undermines user awareness during USB device interactions. This weakness stems from the operating system's inadequate warning mechanisms when processing Human Interface Device functionality over Universal Serial Bus connections, creating a dangerous gap in user protection that malicious actors can exploit through carefully crafted USB data payloads.
The technical flaw manifests in the operating system's failure to provide clear, explicit warnings to users when USB devices attempt to enable additional HID functionality. When a user connects a USB device such as a smartphone that contains malicious code designed to present itself as both a keyboard and mouse, the system does not adequately inform the user of the potential security implications. This lack of proper user notification allows attackers to leverage the legitimate USB HID protocols to execute arbitrary code on the target system. The vulnerability specifically affects the operating system's USB device handling mechanisms and its interaction with HID device classes, where the system accepts and processes HID data without sufficient user consent or awareness of the potential consequences.
The operational impact of this vulnerability is particularly severe as it enables user-assisted remote code execution through seemingly benign USB connections. Attackers can craft USB data that appears legitimate to the operating system while simultaneously implementing malicious HID functionality that can bypass traditional security controls. This attack vector is especially dangerous because it relies on user behavior rather than exploiting system vulnerabilities directly, making it more difficult to detect and prevent through conventional security measures. The attack scenario demonstrates how a user connecting a smartphone to their computer can inadvertently enable malware execution through the HID protocols that the system automatically processes without user intervention.
This vulnerability aligns with CWE-693, which addresses protection mechanism failures, and represents a clear example of inadequate user awareness in security contexts. The attack pattern corresponds to techniques described in the ATT&CK framework under T1059 for command and scripting interpreter and T1210 for exploitation of remote services, where the initial compromise occurs through USB device manipulation rather than network-based attacks. The security implications extend beyond simple code execution to include potential privilege escalation and system compromise, as the HID functionality can be leveraged to inject malicious keystrokes or mouse commands that can manipulate the user's session or system state.
Mitigation strategies for this vulnerability should focus on implementing enhanced user warnings and system controls for USB device connections. Users should be encouraged to disable automatic HID device processing when connecting unknown USB devices, and system administrators should consider implementing USB device policies that restrict HID functionality for untrusted devices. The operating system should be updated to provide explicit warnings when HID devices are detected and to require user confirmation before enabling additional HID capabilities. Additionally, organizations should implement USB device management policies that prevent automatic execution of HID device drivers and consider using USB blocking solutions for environments where such attacks are particularly concerning.