CASPER: Compiler-Assisted Securing of Programs at Runtime

Ensuring the security and integrity of computer systems deployed on the Internet is growing harder. This is especially true in the case of server systems based on open source projects like Linux, Apache, Sendmail, etc. since it is easier for a hacker to get access to the binary format of deployed applications if the source code to the software is publicly accessible. Often, having a binary copy of an application program is enough to help locate security vulnerabilities in the program. In the case of legacy systems where the source code is not available, advanced reverse-engineering and decompilation techniques can be used to construct attacks. This paper focuses on measures that reduce the effectiveness of hackers at conducting large-scale, distributed attacks. The first line of defense involves additional runtime checks that are able to counteract the majority of hacking attacks. Introducing diversity in deployed systems to severely diminish the probability of propagation to other systems helps to prevent effective attacks like the DDOS attack against the DNS root servers in October 21, 2002

ROPocop - Dynamic Mitigation of Code-Reuse Attacks

Control-flow attacks, usually achieved by exploiting a buffer-overflow vulnerability, have been a serious threat to system security for over fifteen years. Researchers have answered the threat with various mitigation techniques, but nevertheless, new exploits that successfully bypass these technologies still appear on a regular basis. In this paper, we propose ROPocop, a novel approach for detecting and preventing the execution of injected code and for mitigating code-reuse attacks such as return-oriented programming (RoP). ROPocop uses dynamic binary instrumentation, requiring neither access to source code nor debug symbols or changes to the operating system. It mitigates attacks by both monitoring the program counter at potentially dangerous points and by detecting suspicious program flows. We have implemented ROPocop for Windows x86 using PIN, a dynamic program instrumentation framework from Intel. Benchmarks using the SPEC CPU2006 suite show an average overhead of 2.4x, which is comparable to similar approaches, which give weaker guarantees. Real-world applications show only an initially noticeable input lag and no stutter. In our evaluation our tool successfully detected all 11 of the latest real-world code-reuse exploits, with no false alarms. Therefore, despite the overhead, it is a viable, temporary solution to secure critical systems against exploits if a vendor patch is not yet available

StackGuard: Automatic Adaptive Detection and Prevention of Buffer-Overflow Attacks

This paper presents a systematic solution to the persistent problem of buffer overflow attacks. Buffer overflow attacks gained notoriety in 1988 as part of the Morris Worm incident on the Internet. While it is fairly simple to fix individual buffer overflow vulnerabilities, buffer overflow attacks continue to this day. Hundreds of attacks have been discovered, and while most of the obvious vulnerabilities have now been patched, more sophisticated buffer overflow attacks continue to emerge. We describe StackGuard: a simple compiler technique that virtually eliminates buffer overflow vulnerabilities with only modest performance penalties. Privileged programs that are recompiled with the StackGuard compiler extension no longer yield control to the attacker, but rather enter a fail-safe state. These programs require no source code changes at all, and are binary-compatible with existing operating systems and libraries. We describe the compiler technique (a simple patch to gcc), as well as a set of variations on the technique that tradeoff between penetration resistance and performance. We present experimental results of both the penetration resistance and the performance impact of this technique

ScaRR: Scalable Runtime Remote Attestation for Complex Systems

The introduction of remote attestation (RA) schemes has allowed academia and industry to enhance the security of their systems. The commercial products currently available enable only the validation of static properties, such as applications fingerprint, and do not handle runtime properties, such as control-flow correctness. This limitation pushed researchers towards the identification of new approaches, called runtime RA. However, those mainly work on embedded devices, which share very few common features with complex systems, such as virtual machines in a cloud. A naive deployment of runtime RA schemes for embedded devices on complex systems faces scalability problems, such as the representation of complex control-flows or slow verification phase. In this work, we present ScaRR: the first Scalable Runtime Remote attestation schema for complex systems. Thanks to its novel control-flow model, ScaRR enables the deployment of runtime RA on any application regardless of its complexity, by also achieving good performance. We implemented ScaRR and tested it on the benchmark suite SPEC CPU 2017. We show that ScaRR can validate on average 2M control-flow events per second, definitely outperforming existing solutions.Comment: 14 page

Survey of Protections from Buffer-Overflow Attacks

Buffer-overflow attacks began two decades ago and persist today. Over that time, many solutions to provide protection from buffer-overflow attacks have been proposed by a number of researchers. They all aim to either prevent or protect against buffer-overflow attacks. As defenses improved, attacks adapted and became more sophisticated. Given the maturity of field and the fact that some solutions now exist that can prevent most buffer-overflow attacks, we believe it is time to survey these schemes and examine their critical issues. As part of this survey, we have grouped approaches into three board categories to provide a basis for understanding buffer-overflow protection schemes

Using Execution Transactions To Recover From Buffer Overflow Attacks

We examine the problem of containing buffer overflow attacks in a safe and efficient manner. Briefly, we automatically augment source code to dynamically catch stack and heap-based buffer overflow and underflow attacks, and recover from them by allowing the program to continue execution. Our hypothesis is that we can treat each code function as a transaction that can be aborted when an attack is detected, without affecting the application's ability to correctly execute. Our approach allows us to selectively enable or disable components of this defensive mechanism in response to external events, allowing for a direct tradeoff between security and performance. We combine our defensive mechanism with a honeypot-like configuration to detect previously unknown attacks and automatically adapt an application's defensive posture at a negligible performance cost, as well as help determine a worm's signature. The main benefits of our scheme are its low impact on application performance, its ability to respond to attacks without human intervention, its capacity to handle previously unknown vulnerabilities, and the preservation of service availability. We implemented a stand-alone tool, DYBOC, which we use to instrument a number of vulnerable applications. Our performance benchmarks indicate a slow-down of 20% for Apache in full-protection mode, and 1.2% with partial protection. We validate our transactional hypothesis via two experiments: first, by applying our scheme to 17 vulnerable applications, successfully fixing 14 of them; second, by examining the behavior of Apache when each of 154 potentially vulnerable routines are made to fail, resulting in correct behavior in 139 of cases

The Cracker Patch Choice: An Analysis of Post Hoc Security Techniques

It has long been known that security is easiest to achieve when it is designed in from the start. Unfortunately, it has also become evident that systems built with security as a priority are rarely selected for wide spread deployment, because most consumers choose features, convenience, and performance over security. Thus security officers are often denied the option of choosing a truly secure solution, and instead must choose among a variety of post hoc security adaptations. We classify security enhancing methods, and compare and contrast these methods in terms of their effectiveness vs. cost of deployment. Our analysis provides practitioners with a guide for when to develop and deploy various kinds of post hoc security adaptations

Extending Hardware Based Mandatory Access Controls to Multicore Architectures

Memory based vulnerabilities have plagued the computer industry since the release of the Morris worm twenty years ago. In addition to buffer overflow attacks like the Morris worm, format strings, ret-libC, and heap double free() viruses have been able to take advantage of pervasive programming errors. A recent example is the unspecified buffer overflow vulnerability present in Mozilla Firefox 3.0. From the past one can learn that these coding mistakes are not waning. A solution is needed that can close off these security shortcomings while still being of minimal impact to the user. Antivirus software makers continuously overestimate the lengths that the everyday user is willing to go to in order to protect his or her system. The ideal protection scheme will be of little or no inconvenience to the user. A technique that fits this niche is one that is built into the hardware. Typical users will never know of the added protection they\u27re receiving because they are getting it by default. Unlike the NX bit technology in modern x86 machines, the correct solution should be mandatory and uncircumventable by user programs. The idea of marking memory as non-executable is maintained but in this case the granularity is refined to the byte level. The standard memory model is extended by one bit per byte to indicate whether the data stored there is trusted or not. While this design is not unique in the architecture field, the issues that arise from multiple processing units in a single system causes complications. Therefore, the purpose of this work is to investigate hardware based mandatory access control mechanisms that work in the multicore paradigm. As a proof of concept, a buffer overflow style attack has been crafted that results in an escalation of privileges for a nonroot user. While effective against a standard processor, a CPU modified to include byte level tainting successfully repels the attack with minimal performance overhead