CVE-2017-3748 in VIBE Mobile Phone
Summary
by MITRE
On Lenovo VIBE mobile phones, improper access controls on the nac_server component can be abused in conjunction with CVE-2017-3749 and CVE-2017-3750 to elevate privileges to the root user (commonly known as 'rooting' or "jail breaking" a device).
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Analysis
by VulDB Data Team • 12/30/2020
The vulnerability identified as CVE-2017-3748 affects Lenovo VIBE mobile devices and represents a critical access control flaw within the nac_server component. This component serves as a network access control server that manages network connectivity and access permissions on the device. The improper access controls create a pathway for malicious actors to bypass security mechanisms that should normally prevent unauthorized access to system-level functions. The vulnerability becomes particularly dangerous when combined with other related vulnerabilities within the same affected product line, specifically CVE-2017-3749 and CVE-2017-3750, which together form a comprehensive exploitation chain that can be leveraged to achieve complete system compromise.
The technical implementation of this vulnerability stems from inadequate validation and authorization checks within the nac_server component. Attackers can exploit this flaw to gain elevated privileges that would normally be restricted to system-level processes or administrators. The vulnerability operates at the kernel level or system service layer, where access controls should enforce strict boundaries between user applications and privileged system functions. When combined with the other vulnerabilities in the CVE-2017-3749 and CVE-2017-3750 series, the attack surface expands significantly, allowing for a multi-stage exploitation process that can ultimately result in root access. This type of vulnerability maps directly to CWE-284 which describes improper access control, and aligns with ATT&CK techniques related to privilege escalation and persistence mechanisms. The nac_server component likely operates with elevated privileges and contains logic that fails to properly validate incoming requests or enforce proper authentication mechanisms.
The operational impact of CVE-2017-3748 is severe and far-reaching for affected Lenovo VIBE device users. Once successfully exploited, the vulnerability enables full system compromise, allowing attackers to execute arbitrary code with root privileges. This level of access provides complete control over device functions including but not limited to data access, network communications, application installation, and system configuration modifications. The implications extend beyond simple data theft to include potential device manipulation, malware deployment, and the establishment of persistent backdoors. Users may experience complete loss of privacy and security guarantees, as the vulnerability effectively nullifies the device's built-in security protections. Organizations deploying these devices in enterprise environments face significant risk of data breaches and unauthorized access to corporate networks through compromised endpoints. The vulnerability also impacts the device's integrity and availability, as attackers can modify system files, disable security features, or render devices inoperable through malicious code execution.
Mitigation strategies for CVE-2017-3748 should prioritize immediate firmware updates from Lenovo, as this vulnerability requires vendor-provided patches to address the underlying access control flaws. Users should disable unnecessary network services and avoid connecting to untrusted networks until patches are applied. Network administrators should implement monitoring for suspicious network activity that might indicate exploitation attempts, particularly focusing on unusual traffic patterns originating from affected devices. The vulnerability's exploitation requires a specific attack chain involving multiple components, so defensive measures should focus on network segmentation and endpoint protection. Organizations should also consider implementing device management solutions that can automatically enforce security updates and monitor for unauthorized modifications. Security professionals should note that this vulnerability represents a classic example of how seemingly isolated access control flaws can combine to create significant security risks, emphasizing the importance of comprehensive security testing and the principle of least privilege implementation. Additionally, the vulnerability highlights the need for robust component-level security testing and the importance of addressing security flaws in interconnected system components rather than treating them in isolation.