Centralized prevention of denial of service attacks

The world has come to depend on the Internet at an increasing rate for communication, e-commerce, and many other essential services. As such, the Internet has become an integral part of the workings of society at large. This has lead to an increased vulnerability to remotely controlled disruption of vital commercial and government operations---with obvious implications. This disruption can be caused by an attack on one or more specific networks which will deny service to legitimate users or an attack on the Internet itself by creating large amounts of spurious traffic (which will deny services to many or all networks). Individual organizations can take steps to protect themselves but this does not solve the problem of an Internet wide attack. This thesis focuses on an analysis of the different types of Denial of Service attacks and suggests an approach to prevent both categories by centralized detection and limitation of excessive packet flows

SecureQEMU: Emulation-based Software Protection Providing Encrypted Code Execution and Page Granularity Code Signing

This research presents an original emulation-based software protection scheme providing protection from reverse code engineering (RCE) and software exploitation using encrypted code execution and page-granularity code signing, respectively. Protection mechanisms execute in trusted emulators while remaining out-of-band of untrusted systems being emulated. This protection scheme is called SecureQEMU and is based on a modified version of Quick Emulator (QEMU) [5]. RCE is a process that uncovers the internal workings of a program. It is used during vulnerability and intellectual property (IP) discovery. To protect from RCE program code may have anti-disassembly, anti-debugging, and obfuscation techniques incorporated. These techniques slow the process of RCE, however, once defeated protected code is still comprehensible. Encryption provides static code protection, but encrypted code must be decrypted before execution. SecureQEMUs\u27 scheme overcomes this limitation by keeping code encrypted during execution. Software exploitation is a process that leverages design and implementation errors to cause unintended behavior which may result in security policy violations. Traditional exploitation protection mechanisms provide a blacklist approach to software protection. Specially crafted exploit payloads bypass these protection mechanisms. SecureQEMU provides a whitelist approach to software protection by executing signed code exclusively. Unsigned malicious code (exploits, backdoors, rootkits, etc.) remain unexecuted, therefore, protecting the system. SecureQEMUs\u27 cache mechanisms increase performance by 0.9% to 1.8% relative to QEMU. Emulation overhead for SecureQEMU varies from 1400% to 2100% with respect to native performance. SecureQEMUs\u27 performance increase is negligible with respect to emulation overhead. Dependent on risk management strategy, SecureQEMU\u27s protection benefits may outweigh emulation overhead

Smashing the Stack with Hydra: The Many Heads of Advanced Polymorphic Shellcode

Recent work on the analysis of polymorphic shellcode engines suggests that modern obfuscation methods would soon eliminate the usefulness of signature-based network intrusion detection methods and supports growing views that the new generation of shellcode cannot be accurately and efficiently represented by the string signatures which current IDS and AV scanners rely upon. In this paper, we expand on this area of study by demonstrating never before seen concepts in advanced shellcode polymorphism with a proof-of-concept engine which we call Hydra. Hydra distinguishes itself by integrating an array of obfuscation techniques, such as recursive NOP sleds and multi-layer ciphering into one system while offering multiple improvements upon existing strategies. We also introduce never before seen attack methods such as byte-splicing statistical mimicry, safe-returns with forking shellcode and syscall-time-locking. In total, Hydra simultaneously attacks signature, statistical, disassembly, behavioral and emulation-based sensors, as well as frustrates offline forensics. This engine was developed to present an updated view of the frontier of modern polymorphic shellcode and provide an effective tool for evaluation of IDS systems, Cyber test ranges and other related security technologies

Intrusion detection systems in wireless ad-hoc networks: detecting worm attacks

As wireless networks become more commonplace, it is important to have methods to detect attacks against them. We have surveyed current open source and commercial wireless intrusion detection systems, and we present our findings. An intrusion detection system utilizing cross-layer detection, which has been designed and implemented, is described. Kismet, in conjunction with Snort and a custom developed CPU usage monitoring tool, is used to detect worm attacks on wireless networks. The process of designing and implementing a computer worm to test the accuracy of the developed system is detailed. The design, implementation, and configuration of the wireless intrusion detection system are presented. After testing how well this system detects the worm, the results are given and discussed, which indicate that the tools we use work well together and can accurately detect a worm attack. We include a discussion on how our intrusion detection system can be broadened into a more useful general framework that can be used in different environments to detect different attacks. Conclusions about the performance of this system and directions of future research are included at the end

ProtoMon: Embedded Monitors for Cryptographic Protocol Intrusion Detection and Prevention

Intrusion Detection Systems (IDS) are responsible for monitoring and analyzing host or network activity to detect intrusions in order to protect information from unauthorized access or manipulation. There are two main approaches for intrusion detection: signature-based and anomaly-based. Signature-based detection employs pattern matching to match attack signatures with observed data making it ideal for detecting known attacks. However, it cannot detect unknown attacks for which there is no signature available. Anomaly-based detection uses machine-learning techniques to create a profile of normal system behavior and uses this profile to detect deviations from the normal behavior. Although this technique is effective in detecting unknown attacks, it has a drawback of a high false alarm rate. In this paper, we describe our anomaly-based IDS designed for detecting malicious use of cryptographic and application-level protocols. Our system has several unique characteristics and benefits, such as the ability to monitor cryptographic protocols and application-level protocols embedded in encrypted sessions, a very lightweight monitoring process, and the ability to react to protocol misuse by modifying protocol response directly

Windows security sandbox framework

Software systems are vulnerable to attack in many different ways. Systems can be poorly implemented which could allow an attacker access to the system through legitimate means such as anonymous access to a server or security controls and access lists can be configured incorrectly which would allow an attacker access to the system by exploiting a logic flaw in the systems configuration. These security vulnerabilities can be limited by implementing software systems properly or in a more restrictive manner. Sandboxing an application allows for interception of a processes system call for verification against a defined policy. A system call can be allowed or denied based on the function being called or can have parameters analyzed and verified against a defined policy. This paper presents a sandboxing framework for Microsoft Windows operating systems. The framework is written entirely in python and uses a modular design which allows for small and simple policies. Profiles can exist for processes which automatically load user policies for a sandbox process --Document

A systematic analysis of defenses against code reuse attacks

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 85-88).In this thesis, we developed a systematic model of the code reuse attack space where facts about attacks and defenses were represented as propositional statements in boolean logic and the possibility of deploying malware was a satisfiability instance. We use the model to analyze the space in two ways: we analyze the defense configurations of a real-world system and we reason about hypothetical defense bypasses. We construct attacks based on the hypothetical defense bypasses. Next, we investigate the control flow graphs enforced by proposed control flow integrity (CFI) systems. We model the behavior of these systems using a graph search. We also develop several code reuse payloads that work within the control flow graph enforced by one proposed CFI defense. Our findings illustrate that the defenses we investigated are not effective in preventing real world attacks.by Kelly Casteel.M. Eng