CVE-2015-3845 in Android
Summary
by MITRE
The Parcel::appendFrom function in libs/binder/Parcel.cpp in Binder in Android before 5.1.1 LMY48M does not consider parcel boundaries during identification of binder objects in an append operation, which allows attackers to obtain a different application's privileges via a crafted application, aka internal bug 17312693.
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2015-3845 resides within the Android Binder IPC mechanism, specifically in the Parcel::appendFrom function located in libs/binder/Parcel.cpp. This flaw represents a critical security issue that undermines the fundamental security model of Android's inter-process communication system. The Binder framework serves as the primary mechanism for communication between applications and system services, making this vulnerability particularly dangerous as it could enable privilege escalation attacks. The vulnerability affects Android versions prior to 5.1.1 LMY48M, indicating a widespread impact across multiple Android releases and highlighting the persistence of such security flaws in mobile operating systems.
The technical root cause of this vulnerability stems from improper boundary checking within the Parcel::appendFrom function. When processing binder objects during append operations, the function fails to properly validate parcel boundaries, allowing attackers to manipulate the data structure in ways that bypass normal security checks. This flaw creates a condition where malicious applications can craft specially formatted parcels that contain binder objects designed to exploit the boundary checking mechanism. The vulnerability specifically relates to how the system identifies and processes binder objects during data transfer operations, where the lack of proper boundary validation enables attackers to inject or manipulate objects that should be restricted to specific applications or processes. This represents a classic case of insufficient input validation and boundary checking that violates fundamental security principles.
The operational impact of CVE-2015-3845 is severe and potentially catastrophic for affected Android devices. Attackers exploiting this vulnerability can gain unauthorized access to privileges belonging to other applications, effectively enabling privilege escalation attacks that bypass Android's application sandboxing mechanisms. This capability allows malicious actors to access sensitive data, perform unauthorized operations, and potentially gain root-level access to the device. The vulnerability's classification as an internal bug (17312693) suggests it was identified within Google's development processes but took considerable time to address, indicating the complexity of the underlying security flaw. The impact extends beyond individual applications to potentially compromise the entire device security model, as the Binder mechanism is fundamental to Android's architecture and is used extensively by system services and applications.
This vulnerability aligns with CWE-129, which addresses improper validation of array indices, and relates to the broader category of buffer overflow and memory corruption issues. The flaw demonstrates characteristics consistent with ATT&CK technique T1068, which involves the use of exploit techniques targeting privilege escalation and process manipulation. The security implications extend to Android's security model where the Binder IPC system is designed to maintain strict boundaries between applications and system services. The vulnerability essentially creates a pathway for attackers to manipulate these boundaries, effectively allowing them to impersonate legitimate applications or system processes. Organizations and users affected by this vulnerability face significant risks including data theft, unauthorized access to personal information, and potential device compromise that could lead to broader security breaches.
The recommended mitigations for CVE-2015-3845 focus on immediate system updates and patches. Android users should immediately upgrade to Android 5.1.1 LMY48M or later versions where the vulnerability has been addressed through proper boundary checking in the Parcel::appendFrom function. System administrators should ensure all affected devices receive the appropriate security updates and should monitor for any attempts to exploit this vulnerability in their environments. Additionally, application developers should review their code for potential reliance on insecure Binder operations and implement additional validation measures where appropriate. The fix implemented by Google addresses the core issue by ensuring proper boundary validation during parcel operations, preventing attackers from manipulating the data structure to gain unauthorized privileges. Organizations should also consider implementing network monitoring solutions to detect potential exploitation attempts and maintain updated threat intelligence regarding similar vulnerabilities in the Android ecosystem.