CVE-2015-3849 in Android
Summary
by MITRE
The Region_createFromParcel function in core/jni/android/graphics/Region.cpp in Region in Android before 5.1.1 LMY48M does not check the return values of certain read operations, which allows attackers to execute arbitrary code via an application that sends a crafted message to a service, aka internal bug 21585255.
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Analysis
by VulDB Data Team • 01/12/2018
The vulnerability identified as CVE-2015-3849 represents a critical security flaw within the Android operating system's graphics handling subsystem, specifically affecting versions prior to 5.1.1 LMY48M. This vulnerability resides in the Region_createFromParcel function located in core/jni/android/graphics/Region.cpp, which is responsible for creating region objects from serialized data received through Android's inter-process communication mechanisms. The flaw manifests when the function fails to properly validate the return values of read operations performed during the deserialization process, creating a potential code execution vector that can be exploited by malicious actors.
The technical nature of this vulnerability stems from inadequate input validation within the Android graphics framework's parcelable object deserialization routine. When an application receives a crafted parcel message containing malformed data, the Region_createFromParcel function proceeds with processing without verifying that all read operations completed successfully. This omission creates a scenario where attackers can manipulate the data flow to cause buffer overflows, memory corruption, or other exploitable conditions that ultimately lead to arbitrary code execution. The vulnerability operates at the JNI (Java Native Interface) layer, bridging the gap between Java application code and native C/C++ implementations, making it particularly dangerous as it can bypass higher-level security controls.
The operational impact of CVE-2015-3849 extends beyond simple privilege escalation, as it enables attackers to execute malicious code with the privileges of the affected service or application. This vulnerability can be exploited through various attack vectors including malicious applications installed on the device, or more insidiously through compromised services that accept user input. The attack typically requires an application to send a specially crafted message to a vulnerable service, leveraging the Android system's IPC mechanisms to deliver the malicious payload. This makes the vulnerability particularly concerning in enterprise environments where applications may have elevated privileges or access to sensitive system resources, as it could enable full system compromise or data exfiltration.
Security researchers have classified this vulnerability under CWE-248, which deals with the exposure of an exception to the calling program, and it aligns with ATT&CK techniques related to privilege escalation and code injection. The vulnerability demonstrates the critical importance of proper input validation and error handling in native code components, particularly those handling serialized data from untrusted sources. Organizations should implement immediate mitigations including updating to Android 5.1.1 LMY48M or later versions, applying security patches, and implementing network-level controls to prevent unauthorized applications from sending malicious parcels to vulnerable services. Additionally, developers should conduct thorough code reviews of native components, particularly those handling parcelable objects, to ensure proper error checking and validation of all read operations. The vulnerability serves as a reminder of the inherent risks in complex systems where multiple layers of abstraction can introduce security gaps that attackers can exploit to gain unauthorized access to system resources.