CVE-2017-0623 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the HTC bootloader could enable a local malicious application to execute arbitrary code within the context of the bootloader. This issue is rated as High because it first requires compromising a privileged process. Product: Android. Versions: Kernel-3.18. Android ID: A-32512358.
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Analysis
by VulDB Data Team • 09/26/2020
The vulnerability identified as CVE-2017-0623 represents a critical elevation of privilege flaw within the HTC bootloader implementation, specifically affecting Android devices running kernel version 3.18. This vulnerability resides at the lowest level of the system architecture, where the bootloader operates with the highest privileges and executes before the operating system loads. The issue stems from insufficient input validation and improper access controls within the bootloader's code execution pathways, creating a potential attack vector that could be exploited by malicious applications with local access to the device. The vulnerability's classification as High severity reflects the substantial risk it poses when combined with the requirement to first compromise a privileged process, which significantly reduces the overall attack surface but does not eliminate the danger. The Android ID A-32512358 indicates this was tracked within Google's internal vulnerability reporting system, highlighting the coordinated disclosure approach typical for such low-level system vulnerabilities.
The technical flaw manifests in the bootloader's handling of specific input parameters during the device boot process, where insufficient sanitization allows for malformed data to be processed without proper validation checks. This weakness enables an attacker with local privileges to craft malicious payloads that can be executed within the bootloader context, effectively bypassing traditional operating system security boundaries. The vulnerability operates at the boundary between hardware and software, where the bootloader's trust zone intersects with the application layer, creating a potential pathway for code injection attacks. The implementation follows patterns that align with CWE-122, which describes buffer overflow conditions in memory management, though the specific manifestation occurs at the bootloader level rather than in user-space applications. This type of vulnerability represents a classic example of insufficient validation of input parameters, where the bootloader fails to properly validate the integrity and authenticity of data passed to its execution environment.
The operational impact of CVE-2017-0623 extends beyond simple privilege escalation, as it fundamentally compromises the device's boot integrity and security chain of trust. Once exploited, the malicious code can modify the bootloader itself, potentially enabling persistent backdoors or complete system compromise that persists across device reboots. The vulnerability creates a persistent threat vector that operates below the operating system level, making detection and remediation particularly challenging. Attackers could leverage this flaw to install rootkits, modify system binaries, or establish unauthorized access points that remain undetected by standard security monitoring tools. The attack requires an initial compromise of a privileged process, which aligns with ATT&CK technique T1068, involving the exploitation of legitimate credentials or privileges to gain access to system resources. This prerequisite significantly increases the attack complexity but does not eliminate the serious security implications, as the attacker could potentially use other vulnerabilities or social engineering techniques to achieve the initial compromise.
Mitigation strategies for this vulnerability require a multi-layered approach focusing on both immediate remediation and long-term security hardening. The most effective immediate solution involves applying the official security patches provided by HTC and Google, which typically include modifications to the bootloader's input validation routines and enhanced access control mechanisms. System administrators should implement device firmware updates as soon as available, particularly targeting the kernel version 3.18 where the vulnerability was identified. Additional protective measures include enabling secure boot mechanisms, implementing device integrity monitoring, and establishing robust application sandboxing policies to prevent unauthorized code execution. Organizations should also consider deploying mobile device management solutions that can monitor for anomalous bootloader behavior and enforce strict update policies. The vulnerability's nature suggests that regular security audits of boot processes, combined with proper access controls and privilege separation, would significantly reduce the risk of exploitation. Furthermore, implementing the principle of least privilege at the bootloader level and maintaining detailed system logs for boot process monitoring would provide early detection capabilities for potential exploitation attempts.