CVE-2018-14856 in Galaxy S6
Summary
by MITRE
Buffer overflow in dhd_bus_flow_ring_create_response in drivers/net/wireless/bcmdhd4358/dhd_pcie.c in the bcmdhd4358 Wi-Fi driver on the Samsung Galaxy S6 SM-G920F G920FXXU5EQH7 allow an attacker (who has obtained code execution on the Wi-Fi) chip to cause the device driver to perform invalid memory accesses. The Samsung ID is SVE-2018-11785.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/21/2020
The vulnerability CVE-2018-14856 represents a critical buffer overflow flaw within the bcmdhd4358 Wi-Fi driver component of Samsung Galaxy S6 devices, specifically affecting the SM-G920F model with firmware version G920FXXU5EQH7. This issue resides in the dhd_bus_flow_ring_create_response function located in the drivers/net/wireless/bcmdhd4358/dhd_pcie.c source file, making it a direct kernel-level security concern that can be exploited through wireless communication channels. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw specifically impacts the PCIe bus communication layer that handles Wi-Fi flow ring creation responses, creating a pathway for malicious code execution within the device's kernel space.
The technical exploitation of this buffer overflow occurs when an attacker successfully compromises the Wi-Fi chip's execution environment and sends specially crafted packets that trigger the vulnerable function. During normal operation, the dhd_bus_flow_ring_create_response function processes flow ring creation responses from the Wi-Fi chip, but due to inadequate input validation and bounds checking, malicious data can overwrite critical memory areas including return addresses, function pointers, or other control data structures. The vulnerability enables an attacker who has already gained code execution capabilities on the Wi-Fi chip to escalate privileges and potentially achieve full device compromise. This type of attack aligns with the ATT&CK framework's privilege escalation techniques, particularly targeting kernel-mode vulnerabilities that allow attackers to bypass user-space protections and gain system-level control.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides a pathway for persistent malware deployment and data exfiltration. An attacker could leverage this flaw to install backdoors, modify system files, or establish persistent communication channels with command and control servers. The Samsung-specific identifier SVE-2018-11785 indicates that this vulnerability was recognized and tracked by Samsung's security team, suggesting the risk extends to millions of affected devices worldwide. The vulnerability's location within the PCIe communication layer makes it particularly dangerous as it operates at a low level where standard operating system protections may be bypassed. Additionally, the attack surface is expanded by the fact that this vulnerability can be triggered through legitimate Wi-Fi network traffic, making detection and prevention challenging for end users who may not be aware of the compromise.
Mitigation strategies for CVE-2018-14856 should include immediate firmware updates from Samsung, which would contain patched versions of the bcmdhd4358 driver with proper bounds checking mechanisms. System administrators and security professionals should implement network monitoring to detect anomalous Wi-Fi traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in kernel-level drivers, particularly regarding input validation and memory management. Organizations should also consider implementing network segmentation and wireless access controls to limit the potential impact of such vulnerabilities. From a defensive perspective, this vulnerability highlights the need for comprehensive security testing of device drivers, especially those handling critical hardware interfaces like PCIe buses. The ATT&CK framework suggests implementing defensive measures such as kernel patch management, monitoring for suspicious kernel memory access patterns, and maintaining up-to-date threat intelligence on mobile device vulnerabilities to prevent exploitation of similar issues in the future.