CVE-2018-5863 in Android
Summary
by MITRE
If userspace provides a too-large WPA RSN IE length in wlan_hdd_cfg80211_set_ie(), a buffer overflow occurs in all Android releases(Android for MSM, Firefox OS for MSM, QRD Android) from CAF using the Linux kernel.
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Analysis
by VulDB Data Team • 02/19/2020
This vulnerability represents a critical buffer overflow condition in the wireless networking subsystem of Android devices that utilize Qualcomm chipsets and the Linux kernel. The flaw exists within the wlan_hdd_cfg80211_set_ie() function which handles wireless network information element processing, specifically when processing WPA RSN (Robust Security Network) information elements. The vulnerability stems from insufficient input validation where the function fails to properly validate the length parameter provided by userspace applications before attempting to copy data into kernel memory buffers. This allows malicious actors to craft specially crafted WPA RSN IE structures with oversized length fields that exceed the allocated buffer boundaries, leading to memory corruption.
The technical implementation of this vulnerability leverages the standard Linux wireless subsystem framework where userspace applications communicate with the kernel through the cfg80211 interface to configure wireless network parameters. When a user provides a WPA RSN IE with an excessively large length value, the kernel function attempts to copy the specified number of bytes into a pre-allocated buffer without proper bounds checking. This creates a classic buffer overflow condition where adjacent memory locations get overwritten, potentially allowing attackers to execute arbitrary code with kernel privileges. The vulnerability affects multiple Android variants including CAF-based Android for MSM, Firefox OS for MSM, and QRD Android releases, indicating it impacts a wide range of devices using Qualcomm wireless chipsets.
The operational impact of this vulnerability is severe as it provides a potential pathway for privilege escalation from userspace to kernel mode, enabling attackers to gain full control over affected devices. Successful exploitation could result in complete system compromise, persistent backdoor installation, data exfiltration, and the ability to modify critical system components. The vulnerability affects all Android releases from CAF using the Linux kernel, making it particularly concerning for mobile device security. Attackers could potentially exploit this through malicious Wi-Fi networks, rogue access points, or by installing compromised applications that trigger the vulnerable code path during wireless configuration operations.
Mitigation strategies should focus on implementing proper input validation and bounds checking within the wlan_hdd_cfg80211_set_ie() function to prevent oversized length fields from causing buffer overflows. The recommended approach includes validating that the provided IE length parameter does not exceed maximum expected values before any memory copying operations occur. Additionally, kernel memory protection mechanisms such as stack canaries, address space layout randomization, and kernel address space layout randomization should be enabled to make exploitation more difficult. Organizations should prioritize applying security patches from device manufacturers and ensure timely updates to mitigate this vulnerability. This aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a significant concern for mobile device security. The vulnerability also maps to ATT&CK technique T1068, which covers local privilege escalation through kernel exploits, highlighting the potential for persistent access and system compromise.