Toward Hardware-assisted Run-time Protection

Thomas Nyman

Toward Hardware-assisted Run-time Protection

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Muistiturvattomien ohjelmointikielten ohjelmistovirheet, kuten puskurin ylivuodot, ovat merkittävä kyberhyökkäysten mahdollistaja. Niiden seurauksena haavoittuvia ohjelmistoja voidaan hyväksikäyttää ajonaikaisten hyökkäysten avulla siten, että niissä laukaistaan tahattomia toimintoja, ja siten päästä luvattomasti käsiksi tietojärjestelmään. Hyökkääjä voi esimerkiksi korruptoimalla muistiviitteitä ohjelmakoodiin kaapata ohjelman suorituksen, ja uudellenohjata prosessorin suorittamaan valitsemiaan käskyjä. Tällaiset kontrollivuohyökkäykset (eng. control-flow attacks) voivat olla erityisen vaarallisia koska niiden avulla voidaan suorittaa mielivaltaista ohjelmakoodia ja jopa ottaa uhrina oleva tietojärjestelmä täysin haltuun. Myös niin sanottujen data-orientoituneiden hyökkäysten (eng. data-oriented attacks) on näytetty mahdollistavan yhtä ilmaisuvoimaisia hyökkäyksiä manipuloimatta uhriohjelman kontrollivuota. Tietoturvatutkimusta on viimeisen kolmenkymmenen vuoden aikana sävyttänyt kilpavarustelu yhä edistyneempien hyökkäysten ja niitä vastaan kehitettyjen turvamekanismien välillä. Ohjelmistotason turvamekanismit, jotka jälkiasentavat muistuturvallisuutta tai kontrollivuon eheyttä (eng. control-flow integrity, CFI) ylläpitäviä mekanismeja C tai C++ -ohjelmiin, estävät useat hyökkäykset, mutta niistä aiheutuvat huomattavat suorituskykykustannukset rajoittavat niiden käyttöönottoa. Ymmärryksessä ajonaikaisista hyökkäyksistä ja niitä vastaan puolustautumisessa on tehty huomattavia edistysaskelia, etenkin sellaisten hyökkäysten suhteen, jotka pyrkivät kiertämään CFI -puolustuskeinot. Käyttännöllisten puolustusmekanismien on kuitenkin tasapainoteltava turvallisuuden, suorituskyvyn ja hyödynnettävyyden välillä. Tämän väitöskirjan tavoitteena on tutkia kuinka laitteistoavusteiset puolustuskeinot voivat suojata ohjelmistoja ajonaikaisilta hyökkäyksiltä ilman huomattavia suorituskykyongelmia. Laitteistoavusteisten puolustuskeinojen on todettu parantavan radikaalisti kykyä havaita hyökkäyksiä, mutta samalla ne vaikeuttavat käyttöönottoa mm. vaatimalla 1) huomattavia muutoksia prosessoriarkkitehtuuriin ja ohjelmistopinoon sekä 2) ylirajoittavaa turvallisuuspolitiikkaa, mikä johtaa yhteensopivuusongelmiin C ja C++ -ohjelmointikielien kanssa. Tämän väitöskirjan tulokset edistävät erityisesti tietämystä seuraavista tutkimusaiheista:1) laitteistoavusteisten puolustuskeinojen soveltaminen sulautettuihin järjestelmiin, mukaan lukien suorituskykyrajoitteiset mikrokontrollerijärjestelmät,2) suoritetun kontrollivuon todistaminen etänä (eng. remote attestation) sulautetulla laitteella tapahtuvien hyökkäysten havaitsemiseksi ja laitteen käyttäytymisen todentamiseksi, sekä3) laitteistoavusteisten puolustuskeinojen kehittäminen CFI:hin perustuvien puolustuskeinoja kiertäviä hyökkäyksiä vastaan.Lopuksi esitän omia huomioitani laitteistoavusteisten puolustuskeinojen nykytilasta, ja potentiaalisista tulevista tutkimusaiheista.

Julkaisun otsikon käännös	Toward Hardware-assisted Run-time Protection
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Asokan, N., Vastuuprofessori
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-0064-8
Sähköinen ISBN	978-952-64-0065-5
Tila	Julkaistu - 2020
OKM-julkaisutyyppi	G5 Tohtorinväitöskirja (artikkeli)

Tutkimusalat

alustaturvallisuus
ajonaikaiset hyökkäykset
laitteistoavusteiset puolustuskeinot

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-64-0065-5

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@phdthesis{62ce4399f43a4ff6bdd8dab4444e83c1,

title = "Toward Hardware-assisted Run-time Protection",

abstract = "Software defects, such as buffer overflows, are prominent enablers of cyberattacks in programs written in memory-unsafe programming languages. As a consequence, vulnerable software programs can be exploited by a sophisticated adversary through run-time attacks to trigger program actions never intended by the software developer, and even to gain unauthorized access to the computer system. For example, the adversary can corrupt memory references (pointers) to program code stored in memory to hijack the flow of execution, and redirect the processor to execute instructions chosen by the adversary. Such control-flow attacks can be particularly devastating, as they can allow arbitrary code execution, and grant complete control of a victim system to an adversary. Recently, data-oriented attacks have been shown to enable equally expressive attacks, without violating the integrity of control-flows within the victim program. Over the past thirty years, there has been an ever-escalating arms race between increasingly sophisticated attacks and defenses to thwart them. Software-only defenses that retrofit programs written in C and C++ with memory-safety or control-flow integrity (CFI) guarantees can be effective against large classes of attacks but are prohibitively expensive. Recently, there have also been significant advances by both researchers and practitioners in understanding and defending against run-time attacks, especially those that attempt to defeat CFI. Practical defenses against run-time attacks must consider how to trade-off security, performance and deployability. The goal of this dissertation is to investigate how hardware-assisted defenses can protect against run-time attacks without incurring a significant performance penalty. Hardware-assisted defenses have been shown to drastically improve the efficiency of attack detection but face various deployment challenges, such as requiring 1) invasive changes to the underlying processor architecture or system software stack, and 2) overly-restrictive security policies, which have difficulties dealing with the inherent flexibility of C and C++, leading to compatibility issues with existing software. In particular the work described in this dissertation provides advances in the following reserch topics: 1) adapting hardware-assisted defenses for embedded systems, including low-end microcontrollers (MCUs), where the challenges for deployment are amplified, 2) remotely attesting the control-flow to learn about run-time attacks, and the dynamic behaviour of an embedded device, and 3) showing how hardware-assisted defenses can defend against attacks that defeat CFI. Finally, I present my own observations about the state-of-the-art and practice in hardware-assisted run-time defenses, and discuss potential directions for future research.",

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author = "Thomas Nyman",

year = "2020",

language = "English",

isbn = "978-952-64-0064-8",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "150",

school = "Aalto University",

}

TY - THES

T1 - Toward Hardware-assisted Run-time Protection

AU - Nyman, Thomas

PY - 2020

Y1 - 2020

N2 - Software defects, such as buffer overflows, are prominent enablers of cyberattacks in programs written in memory-unsafe programming languages. As a consequence, vulnerable software programs can be exploited by a sophisticated adversary through run-time attacks to trigger program actions never intended by the software developer, and even to gain unauthorized access to the computer system. For example, the adversary can corrupt memory references (pointers) to program code stored in memory to hijack the flow of execution, and redirect the processor to execute instructions chosen by the adversary. Such control-flow attacks can be particularly devastating, as they can allow arbitrary code execution, and grant complete control of a victim system to an adversary. Recently, data-oriented attacks have been shown to enable equally expressive attacks, without violating the integrity of control-flows within the victim program. Over the past thirty years, there has been an ever-escalating arms race between increasingly sophisticated attacks and defenses to thwart them. Software-only defenses that retrofit programs written in C and C++ with memory-safety or control-flow integrity (CFI) guarantees can be effective against large classes of attacks but are prohibitively expensive. Recently, there have also been significant advances by both researchers and practitioners in understanding and defending against run-time attacks, especially those that attempt to defeat CFI. Practical defenses against run-time attacks must consider how to trade-off security, performance and deployability. The goal of this dissertation is to investigate how hardware-assisted defenses can protect against run-time attacks without incurring a significant performance penalty. Hardware-assisted defenses have been shown to drastically improve the efficiency of attack detection but face various deployment challenges, such as requiring 1) invasive changes to the underlying processor architecture or system software stack, and 2) overly-restrictive security policies, which have difficulties dealing with the inherent flexibility of C and C++, leading to compatibility issues with existing software. In particular the work described in this dissertation provides advances in the following reserch topics: 1) adapting hardware-assisted defenses for embedded systems, including low-end microcontrollers (MCUs), where the challenges for deployment are amplified, 2) remotely attesting the control-flow to learn about run-time attacks, and the dynamic behaviour of an embedded device, and 3) showing how hardware-assisted defenses can defend against attacks that defeat CFI. Finally, I present my own observations about the state-of-the-art and practice in hardware-assisted run-time defenses, and discuss potential directions for future research.

AB - Software defects, such as buffer overflows, are prominent enablers of cyberattacks in programs written in memory-unsafe programming languages. As a consequence, vulnerable software programs can be exploited by a sophisticated adversary through run-time attacks to trigger program actions never intended by the software developer, and even to gain unauthorized access to the computer system. For example, the adversary can corrupt memory references (pointers) to program code stored in memory to hijack the flow of execution, and redirect the processor to execute instructions chosen by the adversary. Such control-flow attacks can be particularly devastating, as they can allow arbitrary code execution, and grant complete control of a victim system to an adversary. Recently, data-oriented attacks have been shown to enable equally expressive attacks, without violating the integrity of control-flows within the victim program. Over the past thirty years, there has been an ever-escalating arms race between increasingly sophisticated attacks and defenses to thwart them. Software-only defenses that retrofit programs written in C and C++ with memory-safety or control-flow integrity (CFI) guarantees can be effective against large classes of attacks but are prohibitively expensive. Recently, there have also been significant advances by both researchers and practitioners in understanding and defending against run-time attacks, especially those that attempt to defeat CFI. Practical defenses against run-time attacks must consider how to trade-off security, performance and deployability. The goal of this dissertation is to investigate how hardware-assisted defenses can protect against run-time attacks without incurring a significant performance penalty. Hardware-assisted defenses have been shown to drastically improve the efficiency of attack detection but face various deployment challenges, such as requiring 1) invasive changes to the underlying processor architecture or system software stack, and 2) overly-restrictive security policies, which have difficulties dealing with the inherent flexibility of C and C++, leading to compatibility issues with existing software. In particular the work described in this dissertation provides advances in the following reserch topics: 1) adapting hardware-assisted defenses for embedded systems, including low-end microcontrollers (MCUs), where the challenges for deployment are amplified, 2) remotely attesting the control-flow to learn about run-time attacks, and the dynamic behaviour of an embedded device, and 3) showing how hardware-assisted defenses can defend against attacks that defeat CFI. Finally, I present my own observations about the state-of-the-art and practice in hardware-assisted run-time defenses, and discuss potential directions for future research.

KW - platform security

KW - run-time attacks

KW - hardware-assisted defenses

KW - alustaturvallisuus

KW - ajonaikaiset hyökkäykset

KW - laitteistoavusteiset puolustuskeinot

KW - platform security

KW - run-time attacks

KW - hardware-assisted defenses

M3 - Doctoral Thesis

SN - 978-952-64-0064-8

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Toward Hardware-assisted Run-time Protection

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

Science-IT

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