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Tesi Final Marco Oliverio.Pdf
i Abstract Advancements in exploitation techniques call for the need of advanced defenses. Modern operating systems have to face new sophisticate attacks that do not rely on any programming mistake, rather they exploit leaking information from computational side effects (side-channel attacks) or hardware glitches (rowhammer attacks). Mitigating these new attacks poses new challanges and involves delicate trade-offs, balancing security on one side and performance, simplicity, and compatibility on the other. In this disseration we explore the attack surface exposed by page fusion, a memory saving optimization in modern operating systems and, after that, a secure page fusion implementation called VUsion is shown. We then propose a complete and compatible software solution to rowhammer attacks called ZebRAM. Lastly, we show OpenCAL, a free and general libray for the implementation of Cellular Automata, that can be used in several security scenarios. iii Acknowledgements I would like to thank my Supervisor prof. Andrea Pugliese for the encouragement and the extremely valuable advice that put me in a fruitful and exciting research direction. A hearty acknowledgment goes to Kaveh Razavi, Cristiano Giuffrida, Herbert Bos and all the VUSec group of the Vrije Universiteit of Amsterdam. I felt at home from day one and I found myself surrounded by brilliant researchers and good friends. v Contents Abstract i Acknowledgements iii Introduction1 1 VUsion3 1.1 Introduction...................................3 1.2 Page Fusion...................................5 1.2.1 Linux Kernel Same-page Merging...................5 1.2.2 Windows Page Fusion.........................7 1.3 Threat Model..................................8 1.4 Known Attack Vectors.............................8 1.4.1 Information Disclosure.........................8 1.4.2 Flip Feng Shui.............................9 1.5 New Attack Vectors.............................. -
Buffer Overflow Exploits
Buffer overflow exploits EJ Jung A Bit of History: Morris Worm Worm was released in 1988 by Robert Morris • Graduate student at Cornell, son of NSA chief scientist • Convicted under Computer Fraud and Abuse Act, sentenced to 3 years of probation and 400 hours of community service • Now a computer science professor at MIT Worm was intended to propagate slowly and harmlessly measure the size of the Internet Due to a coding error, it created new copies as fast as it could and overloaded infected machines $10-100M worth of damage Morris Worm and Buffer Overflow One of the worm’s propagation techniques was a buffer overflow attack against a vulnerable version of fingerd on VAX systems • By sending special string to finger daemon, worm caused it to execute code creating a new worm copy • Unable to determine remote OS version, worm also attacked fingerd on Suns running BSD, causing them to crash (instead of spawning a new copy) For more history: • http://www.snowplow.org/tom/worm/worm.html Buffer Overflow These Days Most common cause of Internet attacks • Over 50% of advisories published by CERT (computer security incident report team) are caused by various buffer overflows Morris worm (1988): overflow in fingerd • 6,000 machines infected CodeRed (2001): overflow in MS-IIS server • 300,000 machines infected in 14 hours SQL Slammer (2003): overflow in MS-SQL server • 75,000 machines infected in 10 minutes (!!) Attacks on Memory Buffers Buffer is a data storage area inside computer memory (stack or heap) • Intended to hold pre-defined -
Practical C Programming, 3Rd Edition
Practical C Programming, 3rd Edition By Steve Oualline 3rd Edition August 1997 ISBN: 1-56592-306-5 This new edition of "Practical C Programming" teaches users not only the mechanics or programming, but also how to create programs that are easy to read, maintain, and debug. It features more extensive examples and an introduction to graphical development environments. Programs conform to ANSI C. 0 TEAM FLY PRESENTS Table of Contents Preface How This Book is Organized Chapter by Chapter Notes on the Third Edition Font Conventions Obtaining Source Code Comments and Questions Acknowledgments Acknowledgments to the Third Edition I. Basics 1. What Is C? How Programming Works Brief History of C How C Works How to Learn C 2. Basics of Program Writing Programs from Conception to Execution Creating a Real Program Creating a Program Using a Command-Line Compiler Creating a Program Using an Integrated Development Environment Getting Help on UNIX Getting Help in an Integrated Development Environment IDE Cookbooks Programming Exercises 3. Style Common Coding Practices Coding Religion Indentation and Code Format Clarity Simplicity Summary 4. Basic Declarations and Expressions Elements of a Program Basic Program Structure Simple Expressions Variables and Storage 1 TEAM FLY PRESENTS Variable Declarations Integers Assignment Statements printf Function Floating Point Floating Point Versus Integer Divide Characters Answers Programming Exercises 5. Arrays, Qualifiers, and Reading Numbers Arrays Strings Reading Strings Multidimensional Arrays Reading Numbers Initializing Variables Types of Integers Types of Floats Constant Declarations Hexadecimal and Octal Constants Operators for Performing Shortcuts Side Effects ++x or x++ More Side-Effect Problems Answers Programming Exercises 6. -
An In-Depth Study with All Rust Cves
Memory-Safety Challenge Considered Solved? An In-Depth Study with All Rust CVEs HUI XU, School of Computer Science, Fudan University ZHUANGBIN CHEN, Dept. of CSE, The Chinese University of Hong Kong MINGSHEN SUN, Baidu Security YANGFAN ZHOU, School of Computer Science, Fudan University MICHAEL R. LYU, Dept. of CSE, The Chinese University of Hong Kong Rust is an emerging programing language that aims at preventing memory-safety bugs without sacrificing much efficiency. The claimed property is very attractive to developers, and many projects start usingthe language. However, can Rust achieve the memory-safety promise? This paper studies the question by surveying 186 real-world bug reports collected from several origins which contain all existing Rust CVEs (common vulnerability and exposures) of memory-safety issues by 2020-12-31. We manually analyze each bug and extract their culprit patterns. Our analysis result shows that Rust can keep its promise that all memory-safety bugs require unsafe code, and many memory-safety bugs in our dataset are mild soundness issues that only leave a possibility to write memory-safety bugs without unsafe code. Furthermore, we summarize three typical categories of memory-safety bugs, including automatic memory reclaim, unsound function, and unsound generic or trait. While automatic memory claim bugs are related to the side effect of Rust newly-adopted ownership-based resource management scheme, unsound function reveals the essential challenge of Rust development for avoiding unsound code, and unsound generic or trait intensifies the risk of introducing unsoundness. Based on these findings, we propose two promising directions towards improving the security of Rust development, including several best practices of using specific APIs and methods to detect particular bugs involving unsafe code. -
Ensuring the Spatial and Temporal Memory Safety of C at Runtime
MemSafe: Ensuring the Spatial and Temporal Memory Safety of C at Runtime Matthew S. Simpson, Rajeev K. Barua Department of Electrical & Computer Engineering University of Maryland, College Park College Park, MD 20742-3256, USA fsimpsom, [email protected] Abstract—Memory access violations are a leading source of dereferencing pointers obtained from invalid pointer arith- unreliability in C programs. As evidence of this problem, a vari- metic; and dereferencing uninitialized, NULL or “manufac- ety of methods exist that retrofit C with software checks to detect tured” pointers.1 A temporal error is a violation caused by memory errors at runtime. However, these methods generally suffer from one or more drawbacks including the inability to using a pointer whose referent has been deallocated (e.g. with detect all errors, the use of incompatible metadata, the need for free) and is no longer a valid object. The most well-known manual code modifications, and high runtime overheads. temporal violations include dereferencing “dangling” point- In this paper, we present a compiler analysis and transforma- ers to dynamically allocated memory and freeing a pointer tion for ensuring the memory safety of C called MemSafe. Mem- more than once. Dereferencing pointers to automatically allo- Safe makes several novel contributions that improve upon previ- ous work and lower the cost of safety. These include (1) a method cated memory (stack variables) is also a concern if the address for modeling temporal errors as spatial errors, (2) a compati- of the referent “escapes” and is made available outside the ble metadata representation combining features of object- and function in which it was defined. -
Improving Memory Management Security for C and C++
Improving memory management security for C and C++ Yves Younan, Wouter Joosen, Frank Piessens, Hans Van den Eynden DistriNet, Katholieke Universiteit Leuven, Belgium Abstract Memory managers are an important part of any modern language: they are used to dynamically allocate memory for use in the program. Many managers exist and depending on the operating system and language. However, two major types of managers can be identified: manual memory allocators and garbage collectors. In the case of manual memory allocators, the programmer must manually release memory back to the system when it is no longer needed. Problems can occur when a programmer forgets to release it (memory leaks), releases it twice or keeps using freed memory. These problems are solved in garbage collectors. However, both manual memory allocators and garbage collectors store management information for the memory they manage. Often, this management information is stored where a buffer overflow could allow an attacker to overwrite this information, providing a reliable way to achieve code execution when exploiting these vulnerabilities. In this paper we describe several vulnerabilities for C and C++ and how these could be exploited by modifying the management information of a representative manual memory allocator and a garbage collector. Afterwards, we present an approach that, when applied to memory managers, will protect against these attack vectors. We implemented our approach by modifying an existing widely used memory allocator. Benchmarks show that this implementation has a negligible, sometimes even beneficial, impact on performance. 1 Introduction Security has become an important concern for all computer users. Worms and hackers are a part of every day internet life. -
Automatic Discovery of API-Level Vulnerabilities
Automatic Discovery of API-Level Vulnerabilities Vinod Ganapathyy, Sanjit A. Seshiaz, Somesh Jhay, Thomas W. Repsy, Randal E. Bryantz yComputer Sciences Department, zSchool of Computer Science, University of Wisconsin-Madison Carnegie Mellon University fvg|jha|[email protected] fsanjit|[email protected] UW-MADISON COMPUTER SCIENCES TECHNICAL REPORT: UW-CS-TR-1512, JULY 2004. Abstract A system is vulnerable to an API-level attack if its security can be compromised by invoking an allowed sequence of operations from its API. We present a formal framework to model and analyze APIs, and develop an automatic technique based upon bounded model checking to discover API-level vulnerabilities. If a vulnerability exists, our technique produces a trace of API operations demonstrating an attack. Two case studies show the efficacy of our technique. In the first study we present a novel way to analyze printf-family format-string attacks as API-level attacks, and implement a tool to discover them automatically. In the second study, we model a subset of the IBM Common Cryptographic Architecture API, a popular cryptographic key-management API, and automatically detect a previously known vulnerability. 1 Introduction Software modules communicate through application programming interfaces (APIs). Failure to respect an API's usage conventions or failure to understand the semantics of an API may lead to security vulnerabilities. For instance, Chen et al. [13] demonstrated a security vulnerability in sendmail-8.10.1that was due to a misunderstanding of the semantics of UNIX user-id setting commands. A programmer mistakenly assumed that setuid(getuid()) would always drop all privileges. -
The AWK Programming Language
The Programming ~" ·. Language PolyAWK- The Toolbox Language· Auru:o V. AHo BRIAN W.I<ERNIGHAN PETER J. WEINBERGER TheAWK4 Programming~ Language TheAWI(. Programming~ Language ALFRED V. AHo BRIAN w. KERNIGHAN PETER J. WEINBERGER AT& T Bell Laboratories Murray Hill, New Jersey A ADDISON-WESLEY•• PUBLISHING COMPANY Reading, Massachusetts • Menlo Park, California • New York Don Mills, Ontario • Wokingham, England • Amsterdam • Bonn Sydney • Singapore • Tokyo • Madrid • Bogota Santiago • San Juan This book is in the Addison-Wesley Series in Computer Science Michael A. Harrison Consulting Editor Library of Congress Cataloging-in-Publication Data Aho, Alfred V. The AWK programming language. Includes index. I. AWK (Computer program language) I. Kernighan, Brian W. II. Weinberger, Peter J. III. Title. QA76.73.A95A35 1988 005.13'3 87-17566 ISBN 0-201-07981-X This book was typeset in Times Roman and Courier by the authors, using an Autologic APS-5 phototypesetter and a DEC VAX 8550 running the 9th Edition of the UNIX~ operating system. -~- ATs.T Copyright c 1988 by Bell Telephone Laboratories, Incorporated. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopy ing, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Published simultaneously in Canada. UNIX is a registered trademark of AT&T. DEFGHIJ-AL-898 PREFACE Computer users spend a lot of time doing simple, mechanical data manipula tion - changing the format of data, checking its validity, finding items with some property, adding up numbers, printing reports, and the like. -
Buffer Overflows Buffer Overflows
L15: Buffer Overflow CSE351, Spring 2017 Buffer Overflows CSE 351 Spring 2017 Instructor: Ruth Anderson Teaching Assistants: Dylan Johnson Kevin Bi Linxing Preston Jiang Cody Ohlsen Yufang Sun Joshua Curtis L15: Buffer Overflow CSE351, Spring 2017 Administrivia Homework 3, due next Friday May 5 Lab 3 coming soon 2 L15: Buffer Overflow CSE351, Spring 2017 Buffer overflows Address space layout (more details!) Input buffers on the stack Overflowing buffers and injecting code Defenses against buffer overflows 3 L15: Buffer Overflow CSE351, Spring 2017 not drawn to scale Review: General Memory Layout 2N‐1 Stack Stack . Local variables (procedure context) Heap . Dynamically allocated as needed . malloc(), calloc(), new, … Heap Statically allocated Data . Read/write: global variables (Static Data) Static Data . Read‐only: string literals (Literals) Code/Instructions Literals . Executable machine instructions Instructions . Read‐only 0 4 L15: Buffer Overflow CSE351, Spring 2017 not drawn to scale x86‐64 Linux Memory Layout 0x00007FFFFFFFFFFF Stack Stack . Runtime stack has 8 MiB limit Heap Heap . Dynamically allocated as needed . malloc(), calloc(), new, … Statically allocated data (Data) Shared Libraries . Read‐only: string literals . Read/write: global arrays and variables Code / Shared Libraries Heap . Executable machine instructions Data . Read‐only Instructions Hex Address 0x400000 0x000000 5 L15: Buffer Overflow CSE351, Spring 2017 not drawn to scale Memory Allocation Example Stack char big_array[1L<<24]; /* 16 MB */ char huge_array[1L<<31]; /* 2 GB */ int global = 0; Heap int useless() { return 0; } int main() { void *p1, *p2, *p3, *p4; Shared int local = 0; Libraries p1 = malloc(1L << 28); /* 256 MB */ p2 = malloc(1L << 8); /* 256 B */ p3 = malloc(1L << 32); /* 4 GB */ p4 = malloc(1L << 8); /* 256 B */ Heap /* Some print statements .. -
Memory Vulnerability Diagnosis for Binary Program
ITM Web of Conferences 7 03004 , (2016) DOI: 10.1051/itmconf/20160703004 ITA 2016 Memory Vulnerability Diagnosis for Binary Program Feng-Yi TANG, Chao FENG and Chao-Jing TANG College of Electronic Science and Engineering National University of Defense Technology Changsha, China Abstract. Vulnerability diagnosis is important for program security analysis. It is a further step to understand the vulnerability after it is detected, as well as a preparatory step for vulnerability repair or exploitation. This paper mainly analyses the inner theories of major memory vulnerabilities and the threats of them. And then suggests some methods to diagnose several types of memory vulnerabilities for the binary programs, which is a difficult task due to the lack of source code. The diagnosis methods target at buffer overflow, use after free (UAF) and format string vulnerabilities. We carried out some tests on the Linux platform to validate the effectiveness of the diagnosis methods. It is proved that the methods can judge the type of the vulnerability given a binary program. 1 Introduction (or both) the memory area. These headers can contain some information like size, used or not, and etc. Memory vulnerabilities are difficult to detect and diagnose Therefore, we can monitor the allocator so as to especially for those do not crash the program. Due to its determine the base address and the size of the allocation importance, vulnerability diagnosis problem has been areas. Then, check all STORE and LOAD accesses in intensively studied. Researchers have proposed different memory to see which one is outside the allocated area. techniques to diagnose memory vulnerabilities. -
A Type System for Format Strings E
ifact t * r * Comple t te A A n * te W E is s * e C n l l o D C A o * * c T u e m S s E u e S e n I R t v A Type System for Format Strings e o d t y * s E a * a l d u e a t Konstantin Weitz Gene Kim Siwakorn Srisakaokul Michael D. Ernst University of Washington, USA {weitzkon,genelkim,ping128,mernst}@cs.uw.edu ABSTRACT // Untested code (Hadoop) Most programming languages support format strings, but their use Resource r = ... format("Insufficient memory %d", r); is error-prone. Using the wrong format string syntax, or passing the wrong number or type of arguments, leads to unintelligible text // Unchecked input (FindBugs) output, program crashes, or security vulnerabilities. String urlRewriteFormat = read(); This paper presents a type system that guarantees that calls to format(urlRewriteFormat, url); format string APIs will never fail. In Java, this means that the API will not throw exceptions. In C, this means that the API will not // User unaware log is a format routine (Daikon) log("Exception " + e); return negative values, corrupt memory, etc. We instantiated this type system for Java’s Formatter API, and // Invalid syntax for Formatter API (ping-gcal) evaluated it on 6 large and well-maintained open-source projects. format("Unable to reach {0}", server); Format string bugs are common in practice (our type system found Listing 1: Real-world code examples of common programmer 104 bugs), and the annotation burden on the user of our type system mistakes that lead to format routine call failures. -
Automatic Protection from Printf Format String Vulnerabilities
USENIX Association Proceedings of the 10th USENIX Security Symposium Washington, D.C., USA August 13–17, 2001 THE ADVANCED COMPUTING SYSTEMS ASSOCIATION © 2001 by The USENIX Association All Rights Reserved For more information about the USENIX Association: Phone: 1 510 528 8649 FAX: 1 510 548 5738 Email: [email protected] WWW: http://www.usenix.org Rights to individual papers remain with the author or the author's employer. Permission is granted for noncommercial reproduction of the work for educational or research purposes. This copyright notice must be included in the reproduced paper. USENIX acknowledges all trademarks herein. FormatGuard: Automatic Protection From printf Format String Vulnerabilities Crispin Cowan, Matt Barringer, Steve Beattie, and Greg Kroah-Hartman WireX Communications, Inc. http://wirex.com/ Mike Frantzen Jamie Lokier Purdue University CERN Abstract their trouble. Since June 2000, format bugs have eclipsed buffer overflow vulnerabilities for the most In June 2000, a major new class of vulnerabilities called common form of remote penetration vulnerability. “format bugs” was discovered when an vulnerability in WU-FTP appeared that acted almost like a buffer over- There are several obvious solutions to this problem, flow, but wasn’t. Since then, dozens of format string which unfortunately don’t work: vulnerabilities have appeared. This paper describes the format bug problem, and presents FormatGuard: our Remove the %n feature: The printf %n directive is proposed solution. FormatGuard is a small patch to the most dangerous, because it induces printf to glibc that provides general protection against format write data back to the argument list. It has been pro- bugs.