CVE-2017-15828 in Android
Summary
by MITRE
In all android releases(Android for MSM, Firefox OS for MSM, QRD Android) from CAF using the linux kernel, while accessing the keystore in LK, an integer overflow vulnerability exists which may potentially lead to a buffer overflow.
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Analysis
by VulDB Data Team • 05/16/2023
The vulnerability identified as CVE-2017-15828 represents a critical security flaw affecting multiple Android variants including MSM Android, Firefox OS for MSM, and QRD Android platforms. This issue resides within the Linux kernel components used by these systems, specifically during keystore access operations performed in the LK (Linux Kernel) environment. The vulnerability stems from improper handling of integer values during memory allocation processes, creating a pathway for malicious actors to exploit the system's memory management mechanisms. The flaw manifests when the system attempts to calculate buffer sizes for keystore operations, where integer overflow conditions can occur, potentially leading to memory corruption and unauthorized access to sensitive cryptographic data stored within the keystore.
The technical implementation of this vulnerability follows a classic integer overflow pattern that maps to CWE-190, which specifically addresses integer overflow conditions. When the kernel processes keystore access requests, it performs calculations to determine the appropriate buffer sizes needed for storing cryptographic keys and certificates. If these calculations exceed the maximum representable value for the integer type being used, the overflow condition occurs, resulting in a buffer that is significantly smaller than anticipated. This discrepancy creates a scenario where subsequent memory operations can overwrite adjacent memory locations, potentially corrupting critical system data or allowing attackers to inject malicious code into the kernel space. The operational impact extends beyond simple data corruption, as the keystore typically contains sensitive cryptographic material including encryption keys, digital certificates, and other security credentials essential for maintaining system integrity and user privacy.
The exploitation of CVE-2017-15828 aligns with ATT&CK technique T1059.001, which involves the use of command and scripting interpreter for code execution, particularly when attackers leverage buffer overflow conditions to gain elevated privileges within the kernel environment. This vulnerability creates a potential attack surface where malicious actors could craft specially crafted requests to the keystore service, triggering the integer overflow and subsequently achieving arbitrary code execution with kernel-level privileges. The implications are severe as attackers could potentially extract cryptographic keys, modify security certificates, or establish persistent backdoors within the system. The vulnerability affects the fundamental security infrastructure of these mobile platforms, compromising the trust model that relies on secure key storage mechanisms. The integer overflow specifically occurs during the memory allocation phase of keystore operations, making it particularly dangerous as it can be triggered through legitimate system operations while maintaining a low detection profile.
Mitigation strategies for this vulnerability should focus on implementing proper integer overflow checks and bounds validation within the kernel's keystore access routines. System administrators and device manufacturers should prioritize applying security patches that correct the integer calculation logic and introduce proper overflow detection mechanisms. The implementation of stack canaries, address space layout randomization, and kernel memory protection features can provide additional layers of defense against exploitation attempts. Additionally, monitoring for anomalous keystore access patterns and implementing strict input validation for all keystore operations can help detect potential exploitation attempts. Organizations should also consider implementing runtime protection mechanisms that can detect and prevent buffer overflow conditions before they can be exploited, particularly in environments where these vulnerable platforms are deployed. The vulnerability demonstrates the critical importance of rigorous input validation and integer handling in kernel-level code, emphasizing the need for comprehensive security testing and code review processes specifically targeting memory management routines in embedded systems.