Operating system kernels are the security keystone of most computer systems, as they provide the core protection mechanisms. Kernels are in particular responsible for their own security, i.e. they must prevent untrusted user tasks from reaching their level of privilege. We demonstrate that proving such absence of privilege escalation is a pre-requisite for any definitive security proof of the kernel. While prior OS kernel formal verifications were performed either on source code or crafted kernels, with manual or semi-automated methods requiring significant human efforts in annotations or proofs, we show that it is possible to compute such kernel security proofs using fully-automated methods and starting from the executable code of an existing microkernel with no modification, thus formally verifying absence of privilege escalation with high confidence for a low cost. We applied our method on two embedded microkernels, including the industrial kernel AnonymOS: with only 58 lines of annotation and less than 10 minutes of computation, our method finds a vulnerability in a first (buggy) version of AnonymOS and verifies absence of privilege escalation in a second (secure) version.
Software vulnerabilities in access control models can represent a serious threat in a system. In fact, OWASP lists broken access control as number 5 in severity among the top 10 vulnerabilities. In this paper, we study the permission model of an emerging Smart-Home platform, SmartThings, and explore an approach that detects privilege escalation in its permission model. Our approach is based on Model Driven Engineering (MDE) in addition to static analysis. This approach allows for better coverage of privilege escalation detection than static analysis alone, and takes advantage of analyzing free…
AI-based defensive solutions are necessary to defend networks and information assets against intelligent automated attacks. Gathering enough realistic data for training machine learning-based defenses is a significant practical challenge. An intelligent red teaming agent capable of performing realistic attacks can alleviate this problem. However, there is little scientific evidence demonstrating the feasibility of fully automated attacks using machine learning. In this work, we exemplify the potential threat of malicious actors using deep reinforcement learning to train automated agents. We pr…
Modern mobile devices feature multiple wireless technologies, such as Bluetooth, Wi-Fi, and LTE. Each of them is implemented within a separate wireless chip, sometimes packaged as combo chips. However, these chips share components and resources, such as the same antenna or wireless spectrum. Wireless coexistence interfaces enable them to schedule packets without collisions despite shared resources, essential to maximizing networking performance. Today's hardwired coexistence interfaces hinder clear security boundaries and separation between chips and chip components. This paper shows practical…
Register Files (RFs) are the most frequently accessed memories in a microprocessor for fast and efficient computation and control logic. Segment registers and control registers are especially critical for maintaining the CPU mode of execution that determinesthe access privileges. In this work, we explore the vulnerabilities in RF and propose a class of hardware Trojans which can inject faults during read or retention mode. The Trojan trigger is activated if one pre-selected address of L1 data-cache is hammered for certain number of times. The trigger evades post-silicon test since the required…
Recent Microsoft security bulletins show that kernel vulnerabilities are becoming more and more important security threats. Despite the pretty extensive security mitigations many of the kernel vulnerabilities are still exploitable. Successful kernel exploitation typically grants the attacker maximum privilege level and results in total machine compromise. To protect against kernel exploitation, we have developed a tool which statically rewrites the Microsoft Windows kernel as well as other kernel level modules. Such rewritten binary files allow us to monitor control flow transfers during opera…
Grid computing infrastructures need to provide traceability and accounting of their users" activity and protection against misuse and privilege escalation. A central aspect of multi-user Grid job environments is the necessary delegation of privileges in the course of a job submission. With respect to these generic requirements this document describes an improved handling of multi-user Grid jobs in the ALICE ("A Large Ion Collider Experiment") Grid Services. A security analysis of the ALICE Grid job model is presented with derived security objectives, followed by a discussion of existing approa…
One of the main issues in the OS security is providing trusted code execution in an untrusted environment. During executing, kernel-mode drivers dynamically allocate memory to store and process their data: Windows core kernel structures, users' private information, and sensitive data of third-party drivers. All this data can be tampered with by kernel-mode malware. Attacks on Windows-based computers can cause not just hiding a malware driver, process privilege escalation, and stealing private data but also failures of industrial CNC machines. Windows built-in security and existing approaches d…
Agent Skills in the Wild: An Empirical Study of Security Vulnerabilities at Scale
Tianjin University（天津大学）；Southern Cross University（南方十字大学）；School of Cybersecurity, Tianjin University（安全学院，天津大学）；Nanyang Technological University（南洋理工大学）；University of New South Wales（新南威尔士大学）；Griffith University（格里菲斯大学）
Rowhammer attacks that corrupt level-1 page tables to gain kernel privilege are the most detrimental to system security and hard to mitigate. However, recently proposed software-only mitigations are not effective against such kernel privilege escalation attacks. In this paper, we propose an effective and practical software-only defense, called SoftTRR, to protect page tables from all existing rowhammer attacks on x86. The key idea of SoftTRR is to refresh the rows occupied by page tables when a suspicious rowhammer activity is detected. SoftTRR is motivated by DRAM-chip-based target row refres…
The kernel is the most safety- and security-critical component of many computer systems, as the most severe bugs lead to complete system crash or exploit. It is thus desirable to guarantee that a kernel is free from these bugs using formal methods, but the high cost and expertise required to do so are deterrent to wide applicability. We propose a method that can verify both absence of runtime errors (i.e. crashes) and absence of privilege escalation (i.e. exploits) in embedded kernels from their binary executables. The method can verify the kernel runtime independently from the application, at…
