CVE-2016-3758 in Android
Summary
by MITRE
Multiple buffer overflows in libdex/OptInvocation.cpp in DexClassLoader in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01 allow attackers to gain privileges via a crafted application that provides a long filename, aka internal bug 27840771.
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Analysis
by VulDB Data Team • 02/22/2019
The vulnerability identified as CVE-2016-3758 represents a critical buffer overflow flaw within the Android operating system's DexClassLoader implementation. This issue affects multiple Android versions including 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before the specified patch date. The vulnerability stems from improper input validation in the libdex/OptInvocation.cpp component, which handles the processing of dex files during application loading. Attackers can exploit this weakness by crafting malicious applications containing excessively long filenames that trigger buffer overflow conditions during the dex file processing phase.
The technical flaw manifests in the insufficient bounds checking mechanism within the OptInvocation.cpp file where the system fails to properly validate the length of filenames provided during dex file compilation. When a malicious application attempts to load a dex file with an abnormally long filename, the buffer allocated for processing this filename becomes insufficient, leading to memory corruption. This buffer overflow condition creates an opportunity for privilege escalation as the corrupted memory can be manipulated to execute arbitrary code with elevated privileges. The vulnerability operates at the system level where the Android runtime processes application components, making it particularly dangerous as it can be exploited during normal application loading procedures.
The operational impact of this vulnerability is severe as it allows attackers to bypass Android's security model and gain unauthorized access to system resources. An attacker could craft a malicious application that, when installed and executed, would trigger the buffer overflow condition and subsequently escalate privileges to system level access. This capability enables the attacker to perform actions such as modifying system files, accessing sensitive user data, installing additional malicious applications, or even disabling security features. The vulnerability is particularly concerning because it can be exploited through legitimate application installation processes, making detection difficult and potentially affecting a wide range of Android devices across multiple versions. The exploitation requires no special privileges initially, as the vulnerability exists within the core Android system components that handle application loading and execution.
Mitigation strategies for this vulnerability primarily involve applying the relevant security patches released by Google as part of their regular security updates. Organizations and users should ensure their Android devices are updated to versions that contain fixes for this specific buffer overflow condition, particularly upgrading to Android 4.4.4, 5.0.2, 5.1.1, or the corresponding 6.x release that includes the patched DexClassLoader implementation. System administrators should implement robust application vetting procedures to prevent installation of potentially malicious applications that could exploit this vulnerability. Additionally, monitoring for unusual application behavior or unexpected privilege escalation attempts can serve as an early detection mechanism. From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how improper input validation can lead to privilege escalation attacks. The vulnerability also maps to ATT&CK technique T1068, which involves exploiting legitimate credentials or privileges, as the buffer overflow enables unauthorized privilege escalation within the Android environment.