A big safety vulnerability has been recognized in Realtek’s RTL8762E SDK v1.4.0 that enables attackers to use the Bluetooth Low Power (BLE) Safe Connections pairing course of to launch denial-of-service assaults.
The vulnerability, found within the RTL8762EKF-EVB improvement platform, stems from improper validation of protocol state transitions throughout the pairing sequence.
The flaw permits malicious actors to disrupt safe connections by means of rigorously crafted packet injection assaults that require no particular privileges or authentication.
Abstract
1. Realtek RTL8762E SDK v1.4.0 accommodates a essential vulnerability permitting denial-of-service assaults through improper Bluetooth pairing sequence validation.
2. Attackers can inject untimely Pairing Random packets to disrupt BLE connections.
3. Exploitation causes pairing failures and blocks safe BLE connections.
4. Repair requires implementing correct message sequencing within the BLE stack.
Realtek Bluetooth Pairing Protocol Flaw
In keeping with Yang Ting, the vulnerability exploits a elementary flaw within the BLE stack’s implementation of the Safe Connections pairing protocol.
In keeping with the Bluetooth Core Specification v5.3, the pairing course of requires strict message ordering the place the Pairing Random message should solely be despatched after profitable change of Pairing Public Keys.
Nevertheless, the affected Realtek SDK fails to implement this essential sequencing requirement.
The foundation trigger lies in inadequate state validation throughout the Safety Supervisor Protocol (SMP) layer.
The BLE stack processes incoming Pairing Random packets with out verifying that the general public key change section has been accomplished, violating the anticipated state machine transitions outlined within the Bluetooth specification.
This implementation oversight permits the system to simply accept untimely Pairing Random packets, triggering undefined inner states that compromise the pairing course of integrity.
The vulnerability particularly impacts the RTL8762EKF-EVB system operating on Realtek’s RTL8762E SDK v1.4.0, with the flaw residing within the BLE Safe Connections pairing logic part.
Technical evaluation reveals that the state machine violation happens when the system incorrectly processes the untimely packet, resulting in protocol inconsistencies that forestall profitable authentication and connection institution.
The proof-of-concept assault sequence demonstrates the simplicity of exploitation: attackers set up preliminary BLE communication with the RTL8762EKF-EVB system, bypass the right protocol move by sending crafted Pairing Random information prematurely, and efficiently set off the state machine error that aborts the pairing course of.
The assault script pairing_random_before_pairing_public_key.py offers implementation particulars for reproducing this vulnerability.
Remediation Methods
The found vulnerability represents a major safety concern for embedded methods using Realtek’s BLE implementation, because it requires no particular privileges or refined assault instruments.
Beneficial remediation includes implementing complete state validation throughout the SMP layer to make sure strict adherence to protocol specs.
Builders ought to modify the BLE stack to discard any messages obtained out of sequence in line with the SMP state machine necessities, particularly guaranteeing Pairing Random packets are solely accepted after either side have efficiently exchanged Pairing Public Keys.
Organizations utilizing affected Realtek SDK variations ought to prioritize updating to patched firmware variations and contemplate implementing network-level monitoring to detect potential exploitation makes an attempt focusing on their BLE infrastructure.
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