CVE-2018-5850 in Android
Summary
by MITRE
In the function csr_update_fils_params_rso(), insufficient validation on a key length can result in an integer underflow leading to a buffer overflow in all Android releases from CAF (Android for MSM, Firefox OS for MSM, QRD Android) using the Linux Kernel.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/15/2020
The vulnerability identified as CVE-2018-5850 represents a critical security flaw in the wireless networking subsystem of Android devices that utilize Qualcomm chipsets and the Linux kernel. This issue specifically affects the csr_update_fils_params_rso() function within the wireless driver component, which is responsible for handling Fast Initial Link Setup parameters during wireless authentication processes. The flaw manifests when processing key material during the formation of wireless network connections, particularly impacting devices that implement the 802.11i standard for wireless security.
The technical root cause of this vulnerability stems from inadequate input validation within the cryptographic key handling mechanism. When the function processes wireless network keys, it fails to properly validate the length of cryptographic parameters before performing arithmetic operations. This insufficient validation creates a condition where an attacker can manipulate the key length parameter to cause integer underflow during calculation operations. The underflow condition subsequently leads to a buffer overflow scenario where maliciously crafted wireless network parameters can overwrite adjacent memory locations in the kernel space.
This vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, specifically manifesting as a CWE-128 Integer Underflow in the context of memory management. The operational impact of this flaw is severe as it allows for arbitrary code execution within the kernel space, potentially enabling attackers to escalate privileges and gain full control over affected devices. The vulnerability affects all Android releases utilizing Qualcomm's Android for MSM, Firefox OS for MSM, and QRD Android platforms, creating a widespread attack surface across numerous mobile devices and IoT implementations that rely on Qualcomm's wireless chipsets.
The exploitation of this vulnerability requires an attacker to be within range of a targeted wireless network and to craft malicious wireless network parameters that trigger the specific integer underflow condition. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation. The buffer overflow condition creates opportunities for memory corruption that can be leveraged to execute malicious code with kernel-level privileges, potentially leading to complete device compromise. The vulnerability's impact extends beyond individual device security to encompass broader network security implications, as compromised devices could serve as entry points for larger-scale attacks within wireless networks.
Mitigation strategies for this vulnerability require immediate patching of affected Android versions and kernel implementations. Device manufacturers should prioritize updating their firmware to include fixes that properly validate cryptographic key lengths before arithmetic operations. Security researchers recommend implementing bounds checking mechanisms and ensuring proper integer overflow protection in all cryptographic parameter handling functions. Additionally, network administrators should consider implementing wireless network segmentation and monitoring for anomalous wireless traffic patterns that might indicate exploitation attempts. The fix should include comprehensive input validation that prevents malicious key length values from reaching the arithmetic operations that cause the underflow condition, thereby preventing the subsequent buffer overflow that enables privilege escalation attacks.