CVE-2016-8661 in Little Snitch
Summary
by MITRE
Little Snitch version 3.0 through 3.6.1 suffer from a buffer overflow vulnerability that could be locally exploited which could lead to an escalation of privileges (EoP) and unauthorised ring0 access to the operating system. The buffer overflow is related to insufficient checking of parameters to the "OSMalloc" and "copyin" kernel API calls.
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Analysis
by VulDB Data Team • 06/01/2019
The vulnerability identified as CVE-2016-8661 affects Little Snitch versions 3.0 through 3.6.1, representing a critical buffer overflow flaw that exists within the kernel-level components of this network monitoring and control software. This vulnerability stems from inadequate parameter validation within the operating system's memory management APIs, specifically targeting the OSMalloc and copyin kernel functions that are fundamental to memory allocation and data transfer operations. The flaw creates a pathway for local attackers to exploit the system's memory handling mechanisms and potentially achieve unauthorized elevation of privileges to the highest privilege level known as ring0 access.
The technical exploitation of this vulnerability occurs through the manipulation of kernel API calls that process memory allocation and data copying operations. When Little Snitch processes network traffic or performs its monitoring functions, it relies on these kernel APIs to manage memory resources and transfer data between user space and kernel space. The insufficient parameter checking in OSMalloc and copyin functions allows an attacker to provide malformed input that exceeds the allocated buffer boundaries, causing memory corruption that can be leveraged to execute arbitrary code with kernel-level privileges. This type of vulnerability falls under the CWE-121 buffer overflow category, which specifically addresses issues where data written to a buffer extends beyond its allocated bounds.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete control over the target system's kernel operations. With ring0 access, an attacker can bypass all operating system security mechanisms, modify system files, install malicious software, and potentially access all user data without detection. The vulnerability's local exploitation requirement means that an attacker must already have a foothold on the system through other means such as a legitimate user account or a different vulnerability, but once achieved, the privilege escalation provides access to the most sensitive system operations. This makes the vulnerability particularly dangerous in environments where users may have legitimate access to systems but could be compromised through social engineering or other attack vectors.
The security implications of this vulnerability align with the ATT&CK framework's privilege escalation techniques, specifically targeting the T1068 privilege escalation and T1543 persistent threats that can be achieved through kernel-level exploitation. Organizations running affected versions of Little Snitch face significant risk of system compromise, as the vulnerability can be exploited to establish persistent backdoors or to conduct advanced persistent threats that are extremely difficult to detect and remove. The vulnerability also demonstrates the importance of proper input validation and parameter checking in kernel-level code, as even small oversights in memory management can result in complete system compromise. Organizations should immediately update to patched versions of Little Snitch and conduct thorough security assessments to ensure no exploitation has occurred, while also implementing monitoring for suspicious kernel-level activities that might indicate successful exploitation of this vulnerability.