CVE-2015-8889 in Android
Summary
by MITRE
The aboot implementation in the Qualcomm components in Android before 2016-07-05 on Nexus 6P devices omits the recovery PIN feature, which has unspecified impact and attack vectors, aka Android internal bug 28822677 and Qualcomm internal bug CR804067.
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability identified as CVE-2015-8889 represents a critical security flaw in the aboot implementation within Qualcomm components of Android devices, specifically affecting Nexus 6P devices prior to the 2016-07-05 security update. This issue stems from the omission of a crucial recovery PIN feature that should have been implemented to protect device boot processes and prevent unauthorized access during recovery operations. The vulnerability is classified under the CWE-310 cryptographic weakness category, as it involves the absence of proper authentication mechanisms during device boot sequences, creating potential attack vectors for malicious actors seeking to compromise device integrity. The Android internal bug identifier 28822677 and Qualcomm internal bug CR804067 highlight the cross-vendor nature of this issue, indicating that both Google and Qualcomm recognized the severity of the missing security feature.
The technical implementation flaw lies in the aboot bootloader component which is responsible for managing the device boot process and ensuring that only authorized software can execute during system startup. When the recovery PIN feature is omitted, it creates a significant gap in the device's security architecture that could allow attackers to bypass normal authentication procedures and gain access to the device's recovery mode. This weakness enables potential exploitation through various attack vectors including but not limited to unauthorized firmware flashing, system partition modification, and device root access. The unspecified impact and attack vectors suggest that the flaw could be leveraged in multiple ways depending on the attacker's capabilities and the specific device configuration. According to the ATT&CK framework, this vulnerability maps to techniques involving bootkit creation and low-level system access, as attackers could potentially modify the boot process to maintain persistence.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass broader security implications for device integrity and user data protection. Devices affected by this flaw become susceptible to malicious actors who can exploit the missing recovery PIN mechanism to install unauthorized software, modify system files, or even perform complete device compromise. The vulnerability affects the fundamental trust model of the Android security architecture, particularly concerning the verified boot process and the integrity of the device's boot chain. Organizations and individuals using affected Nexus 6P devices face significant risks including potential data breaches, device hijacking, and the possibility of creating persistent backdoors within the device's boot process. The lack of a recovery PIN means that legitimate recovery operations could be bypassed, potentially preventing users from properly restoring their devices while simultaneously opening pathways for malicious recovery operations.
Mitigation strategies for CVE-2015-8889 primarily focus on applying the relevant security patches released by Google and Qualcomm, which would restore the missing recovery PIN functionality in the aboot implementation. Users should ensure their devices receive the 2016-07-05 security update or later, which addresses this specific vulnerability by implementing proper recovery PIN authentication mechanisms. System administrators and security professionals should also consider implementing additional monitoring measures to detect unauthorized boot process modifications and regularly verify the integrity of device boot chains. The vulnerability underscores the importance of proper bootloader security implementation and highlights the need for comprehensive security testing of low-level system components. Organizations should also maintain awareness of the ATT&CK techniques that exploit similar bootloader vulnerabilities and implement appropriate defensive measures including secure boot enforcement and regular security audits of device firmware components.