CVE-2019-2046 in Android
Summary
by MITRE
In CalculateInstanceSizeForDerivedClass of objects.cc, there is possible memory corruption due to an integer overflow. This could lead to remote code execution in the proxy auto-config with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9 Android ID: A-117556220
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Analysis
by VulDB Data Team • 06/08/2020
The vulnerability described in CVE-2019-2046 represents a critical memory corruption issue within the Android operating system's JavaScript engine implementation. This flaw exists in the CalculateInstanceSizeForDerivedClass function located in objects.cc, which is part of the V8 JavaScript engine used by Android's web browser and web-based applications. The vulnerability stems from an integer overflow condition that can occur during memory allocation calculations for derived class instances, creating a scenario where the system allocates insufficient memory for objects that may subsequently exceed their allocated boundaries.
The technical nature of this vulnerability places it squarely within the category of memory safety issues, specifically manifesting as an integer overflow that can lead to memory corruption. This type of vulnerability is classified under CWE-190, Integer Overflow or Wraparound, which occurs when a program performs a calculation using integer values that exceed the maximum value that can be represented by the integer type. The flaw allows attackers to manipulate memory allocation calculations in a way that creates buffer overflows or underflows, potentially enabling arbitrary code execution through carefully crafted JavaScript code.
The operational impact of this vulnerability is particularly severe as it affects multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9.0, representing a substantial portion of Android devices in the wild. The vulnerability specifically impacts the proxy auto-config functionality, which is commonly used by Android browsers and web applications to automatically configure network proxy settings. The attack vector requires no user interaction for exploitation, making it particularly dangerous as it can be triggered automatically when a device encounters malicious JavaScript content or when a malicious website attempts to leverage the vulnerability during normal browsing activities. This automatic exploitation capability significantly increases the attack surface and reduces the effectiveness of user-based security controls.
The potential for remote code execution without additional privileges makes this vulnerability especially concerning from a security perspective. Attackers can leverage this flaw to execute arbitrary code on affected devices, potentially gaining complete control over the affected Android system. The vulnerability's presence in the V8 JavaScript engine means that any application or service that processes JavaScript content could be at risk, including web browsers, web-based applications, and even some system components that rely on JavaScript execution. The lack of user interaction requirements eliminates the need for social engineering attacks or user deception, making this vulnerability particularly effective for automated exploitation campaigns.
Mitigation strategies for this vulnerability primarily focus on prompt system updates and patches provided by Google and device manufacturers. Organizations and users should immediately apply the security patches released as part of the Android security updates, particularly those addressing the specific integer overflow in the V8 JavaScript engine. Network administrators should consider implementing web filtering solutions that can detect and block malicious JavaScript content that attempts to exploit this vulnerability. Additionally, the implementation of sandboxing mechanisms and strict content security policies can help reduce the potential impact of exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and code execution, specifically targeting the execution of malicious code within the browser context. The vulnerability also aligns with defensive techniques that emphasize the importance of keeping software components updated and implementing proper memory management practices to prevent integer overflow conditions. Organizations should also consider monitoring for suspicious JavaScript execution patterns and implementing network-level protections against known malicious domains that may attempt to exploit this vulnerability.