CVE-2018-9568 in Android
Summary
by MITRE
In sk_clone_lock of sock.c, there is a possible memory corruption due to type confusion. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: Android kernel. Android ID: A-113509306. References: Upstream kernel.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2018-9568 represents a critical type confusion issue within the Android kernel's socket implementation, specifically in the sk_clone_lock function located in sock.c. This flaw manifests as a potential memory corruption vulnerability that can be exploited for local privilege escalation without requiring any additional execution privileges or user interaction. The vulnerability resides in the kernel-level socket locking mechanism where improper type handling leads to memory corruption during socket cloning operations. The issue affects Android kernel versions and was tracked under Android ID A-113509306, with upstream kernel references indicating this represents a fundamental flaw in the kernel's socket subsystem implementation. The type confusion occurs when the kernel fails to properly validate or handle different socket object types during the cloning process, creating opportunities for malicious code to manipulate memory layout and execute arbitrary code with elevated privileges.
The technical exploitation of this vulnerability leverages the fundamental flaw in how the kernel manages socket object references and locks during the cloning operation. When sk_clone_lock is invoked, the system attempts to create a copy of a socket structure while maintaining proper locking semantics. However, due to inadequate type checking mechanisms, an attacker can manipulate the socket object's internal structure to cause the kernel to treat one type of data as another, leading to memory corruption. This type confusion allows for arbitrary memory writes and potentially code execution within kernel space, which directly translates to local privilege escalation. The vulnerability operates at the kernel level where the distinction between different socket types becomes blurred, causing the kernel to execute incorrect operations on memory regions that should remain protected. This flaw directly relates to CWE-121 and CWE-122 categories, which address stack-based buffer overflow and heap-based buffer overflow conditions that can result from improper type handling and memory management.
The operational impact of CVE-2018-9568 extends beyond simple privilege escalation as it represents a significant security weakness in Android's kernel architecture that can be exploited by any local user or application with access to socket operations. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be triggered automatically without any user involvement, potentially allowing malicious applications to gain root access or escalate their privileges to the highest system level. Attackers can leverage this vulnerability to bypass Android's security model, gain access to protected system resources, and potentially compromise the entire device. The exploitation process typically involves creating specific socket objects that trigger the type confusion during the cloning operation, allowing for memory corruption that can be leveraged to execute arbitrary code with kernel privileges. This vulnerability directly maps to attack techniques described in the ATT&CK framework under privilege escalation tactics, specifically targeting kernel-level exploitation methods. The vulnerability's impact is compounded by the fact that Android devices commonly run applications with broad network access permissions, increasing the likelihood of exploitation.
Mitigation strategies for CVE-2018-9568 require immediate patching of affected Android kernel versions through official security updates from device manufacturers and Google. System administrators should implement the latest security patches as soon as they become available, particularly focusing on kernel updates that address socket object handling and type validation mechanisms. Device manufacturers should prioritize rolling out security updates to all affected Android versions and ensure proper testing of patches to avoid regressions in functionality. Additional defensive measures include implementing kernel memory protection mechanisms such as stack canaries, address space layout randomization, and kernel address space layout randomization to make exploitation more difficult. Network monitoring and anomaly detection should be enhanced to identify suspicious socket operations that might indicate exploitation attempts. The vulnerability's nature suggests that comprehensive kernel hardening should be implemented alongside traditional security measures, including code review processes that specifically target type handling and memory management functions in kernel code. Organizations should also consider implementing runtime protections and monitoring for unauthorized privilege escalation attempts, as well as maintaining detailed audit logs of socket operations for forensic analysis purposes.