CVE-2020-0199 in Android
Summary
by MITRE
In TimeCheck::TimeCheckThread::threadLoop of TimeCheck.cpp, there is a possible use-after-free due to a race condition. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-142142406
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability identified as CVE-2020-0199 represents a critical use-after-free condition within the Android TimeCheck component, specifically within the TimeCheckThread::threadLoop function in TimeCheck.cpp. This flaw exists in the Android 10 operating system and is classified as a race condition vulnerability that can potentially lead to local information disclosure. The vulnerability stems from improper synchronization mechanisms that allow concurrent access to shared memory resources without adequate protection against simultaneous read and write operations.
The technical implementation of this vulnerability involves a race condition where multiple threads attempt to access the same memory location without proper mutual exclusion controls. When TimeCheckThread::threadLoop executes, it processes time-related operations that may involve memory allocation and deallocation cycles. The race condition occurs when one thread frees memory while another thread attempts to access that same memory location, creating a use-after-free scenario. This condition is particularly dangerous because it can allow malicious code to read data from freed memory locations, potentially exposing sensitive information that was previously stored in those memory regions.
From an operational perspective, exploitation of this vulnerability requires local system execution privileges, meaning an attacker must already have access to the device with system-level permissions. However, the impact is significant as it enables local information disclosure, which can expose sensitive data that was previously stored in memory locations that have been freed but not properly sanitized. This could include authentication tokens, personal information, or other confidential data that applications have processed. The vulnerability demonstrates the importance of proper memory management and synchronization mechanisms in system-level components that handle time-related functions and threading operations.
The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions, and represents a classic example of race condition exploitation in multi-threaded environments. It also relates to ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for local privilege escalation, as the vulnerability requires system privileges for exploitation but can lead to further compromise of the system's integrity. The Android ID A-142142406 indicates this was properly tracked within the Android security framework, highlighting the severity of the issue in mobile operating system environments where time synchronization and system threading are critical components.
Mitigation strategies for this vulnerability should focus on implementing proper synchronization mechanisms such as mutex locks or atomic operations to prevent concurrent access to shared resources. The fix should involve ensuring that memory deallocation occurs only after all threads have completed their access to the memory location, or by using reference counting mechanisms that prevent premature deallocation. Additionally, input validation and proper error handling should be implemented to detect and prevent the conditions that lead to the race state. System administrators should ensure that devices are updated with the latest security patches that address this specific vulnerability, as the use-after-free condition can potentially be exploited to gain unauthorized access to sensitive system information.