CVE-2018-14853 in Galaxy S6
Summary
by MITRE
A NULL pointer dereference in dhd_prot_txdata_write_flush in drivers/net/wireless/bcmdhd4358/dhd_msgbuf.c in the bcmdhd4358 Wi-Fi driver on the Samsung Galaxy S6 SM-G920F G920FXXU5EQH7 allows an attacker (who has obtained code execution on the Wi-Fi chip) to cause the device to reboot. The Samsung ID is SVE-2018-11783.
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Analysis
by VulDB Data Team • 04/21/2020
This vulnerability represents a critical NULL pointer dereference flaw within the bcmdhd4358 Wi-Fi driver component of Samsung Galaxy S6 devices. The issue specifically occurs in the dhd_prot_txdata_write_flush function located at drivers/net/wireless/bcmdhd4358/dhd_msgbuf.c, where improper input validation leads to a scenario where a null pointer is dereferenced during wireless data transmission operations. The vulnerability is particularly concerning because it can be exploited by an attacker who has already achieved code execution on the Wi-Fi chip itself, making it a privilege escalation issue within the wireless subsystem. This flaw falls under CWE-476 which specifically addresses NULL pointer dereference conditions that can lead to system instability and potential denial of service scenarios. The attack vector requires the adversary to have already compromised the Wi-Fi chip's execution environment, which aligns with techniques described in the ATT&CK framework under T1059.007 for command and script interpreter execution, suggesting that the attacker must first establish a foothold within the wireless processing domain before leveraging this specific vulnerability.
The operational impact of this vulnerability extends beyond simple device rebooting to potentially creating a persistent denial of service condition that could be exploited in targeted attacks against mobile devices. When the NULL pointer dereference occurs during the dhd_prot_txdata_write_flush operation, the kernel crashes and reboots the entire device, effectively disrupting all wireless communications and potentially providing an attacker with a reliable method for maintaining persistent access to the target device. This behavior represents a significant security concern for mobile devices where wireless connectivity is essential for normal operation and where such a vulnerability could be leveraged to create a reliable attack vector for device compromise. The Samsung-specific identifier SVE-2018-11783 indicates that this vulnerability was properly acknowledged and tracked within Samsung's security vulnerability management system, demonstrating the company's awareness of the issue and its potential impact on device security. The vulnerability's location within the wireless driver stack means that it operates at a low level within the device's operating system, making exploitation more reliable and potentially harder to detect compared to higher-level application vulnerabilities.
Mitigation strategies for this vulnerability should focus on both immediate device-level protections and long-term architectural improvements to prevent similar issues in wireless driver implementations. Device users should ensure their Samsung Galaxy S6 devices are updated with the latest security patches provided by Samsung, as the company would have released firmware updates addressing this specific NULL pointer dereference issue. System administrators and security teams should implement network monitoring to detect unusual reboot patterns or wireless communication disruptions that could indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and null pointer checks in kernel-level drivers, particularly those handling critical wireless communication protocols. Security professionals should also consider implementing network segmentation and monitoring to prevent attackers from establishing code execution on the Wi-Fi chip in the first place, as this vulnerability requires such pre-existing compromise to be effective. Organizations deploying mobile devices should also consider implementing device integrity monitoring solutions that can detect unauthorized modifications to wireless driver components, as this type of vulnerability is often exploited as part of broader attack chains targeting mobile device security. The ATT&CK framework suggests that such vulnerabilities should be monitored as potential persistence mechanisms, particularly when combined with other wireless-based attack vectors that could enable attackers to maintain long-term access to target devices.