Fine-grained code analysis in the context of malware is a complex and challenging task that provides insight into malware code-layers (polymorphic/metamorphic), its data encryption/decryption engine, its memory layout etc., important pieces of information that can be used to detect and counter the malware and its variants. Current research in fine-grained code analysis can be categorized into static and dynamic approaches. Static approaches have been tailored towards malware and allow exhaustive fine-grained malicious code analysis, but lack support for self-modifying code, have limitations related to code-obfuscations and face the undecidability problem. Given that most if not all malware employ self-modifying code and code-obfuscations, poses the need to analyze them at runtime using dynamic approaches. However, current dynamic approaches for fine-grained code analysis are not tailored specifically towards malware and lack support for multithreading, self-modifying/self-checking code and are easily detected and countered by ever-evolving anti-analysis tricks employed by malware. To address this problem, we propose a powerful dynamic fine-grained malicious code analysis framework, codenamed Cobra, to combat malware that are becoming increasingly hard to analyze. Our goal is to provide a stealth, efficient, portable and easy-to-use framework supporting multithreading, self-modifying/self-checking code and any form of code obfuscation in both user- and kernel-mode on commodity operating systems. Cobra cannot be detected or countered and can be dynamically and selectively deployed on malware specific code-streams while allowing other code-streams to execute as is. We also illustrate the framework utility by describing our experience with a tool employing Cobra to analyze a real-world malware

Microscopic analysis of malicious code (malware) requires the aid of a variety of powerful tools. Chief among them is a debugger that enables runtime binary analysis at an instruction level. One of the important services provided by a debugger is the ability to stop execution of code at an arbitrary point during runtime, using breakpoints. Software breakpoints support an unlimited number of breakpoint locations by changing the code being debugged so that it can be interrupted during runtime. Most, if not all, malware are very sensitive to code modification with self-modifying and/or self-checking (SM-SC) capabilities, rendering the use of software breakpoints limited in their scope. Hardware breakpoints supported by the underlying processor, on the other hand, use a subset of the processor register set and exception mechanisms to provide breakpoints that do not entail code modification. This makes hardware breakpoints the most powerful breakpoint mechanism for malware analysis. However, current processors provide a very limited number of hardware breakpoints (typically 2-4 locations). Thus, a serious restriction is imposed on the debugger to set a desired number of breakpoints without resorting to the limited alternative of software breakpoints. Also, with the ever evolving nature of malware, there are techniques being employed that prevent the use of hardware breakpoints. This calls for a new breakpoint mechanism that retains the features of hardware breakpoints while providing an unlimited number of breakpoints, which cannot be detected or countered. In this paper, we present the concept of stealth breakpoints and discuss the design and implementation of VAMPiRE, a realization of this concept. VAMPiRE cannot be detected or countered and provides unlimited number of breakpoints to be set on code, data, and I/O with the same precision as that of hardware breakpoints. It does so by employing a subtle combination of simple stealth techniques using virtual memory and hardware single-stepping mechanisms that are available on all processors, old and new. This technique makes VAMPiRE portable to any architecture, providing powerful breakpoint ability similar to hardware breakpoints for microscopic malware analysis

Two important aspects that any study of message communication has to address are routing and admission control. The routing problem seeks to find a route for a channel and admission control involves assessing the ability to meet the demands of a channel along the chosen route. Most efforts in the area of real-time communication have been directed, primarily towards the admission control problem, not many have been targeted rewards the routing problem. The authors show that these two problems are inter-related. They address these two problems in a general framework that can abstract many practical scenarios. They assume the use of an arbitrary dynamic/fixed priority link level scheduling, thereby increasing the utility of the derived results. Their approaches for both routing and admission control are based on extending a result we have derived in a different context, viz., task scalability. A simulation study, was performed to study the effectiveness of their approach in improving both utilization of the link and admissibility of channels.

With the proliferation of scheduling algorithms there is a growing need to test these schedulers for their validity not just at design time but also as the system evolves. This implies that the schedulability analysis has to be robust. In this study, we identify a few often posed questions that address the robustness of schedulability analyses. First these questions are dealt in the context of uniprocessor systems and then we handle some of their extensions in a more general context of end-to-end systems. We show that these questions are closely related to a more general problem. We present a solution to this problem. An intuitive proof of correctness and optimality of the solution technique are presented.