上海交通大学：云安全（PPT讲稿）Cloud Security

Cloud Security Group V for Vendetta Wei Mao, Xiaolong Huang, Han Song 2017524

Cloud Security Group: V for Vendetta Wei Mao, Xiaolong Huang, Han Song 2017.5.24

Outline Cloud environment Security problems in cloud How to protect applications against Hypervisor/OS in cloud Intel SGX, protecting applications against OS SCONE(OSDI'16), using Intel SGX How to protect user data against applications in cloud yoan(OSDI'16), using Nacl (s&P09)and Intel SGX How to verify network security in cloud TenantGuard(NDSS'17), verifying network isolation in cloud

Outline • Cloud environment & Security problems in cloud • How to protect applications against Hypervisor/OS in cloud • Intel SGX, protecting applications against OS • SCONE (OSDI’16), using Intel SGX • How to protect user data against applications in cloud • Ryoan (OSDI’16), using NaCl (S&P’09) and Intel SGX • How to verify network security in cloud • TenantGuard (NDSS’17)， verifying network isolation in cloud

Cloud Environment Terminal User Access service jug Personal health data A VM VM VM Deploy service in VM,/ through network 卜 ypervisor Amazon ec2 23andMe Manage platform through network Service Provider Cloud Operator

Cloud Environment Hypervisor VM App VM App VM App Cloud Operator Terminal User Service Provider Deploy service in VM, through network Manage platform, through network Access service, through network 23andMe Amazon EC2 Personal health data

Problems in cloud security Hypervisor protect the cloud platform by virtualization, but who protects VM, A pp, user s data Computing resources are leased from cloud platform not owned by user. Hypervisor/os has absolute privileges of vM, app, data. App tself cannot resist os's attack Hypervisor/OS may not be trustable

Problems in cloud security • Hypervisor protect the cloud platform by virtualization, but who protects VM, App, user’s data ? • Computing resources are leased from cloud platform, not owned by user. • Hypervisor/OS has absolute privileges of VM, app, data. App itself cannot resist OS’s attack • Hypervisor/OS may not be trustable

is hypervisor/OS not trustable Too big TCB(Trusted Computing Base) to be bug-free TCB: the parts that are trusted Process never trust another process, but trusts all its threads OS never trust a process, but trusts hardware Hypervisor never trust a VM, but trust hardware The tcB in cloud is very big, explained later Cloud operators themselves may be potential adversaries

Why is hypervisor/OS not trustable • Too big TCB (Trusted Computing Base) to be bug-free • TCB: the parts that are trusted • Process never trust another process, but trusts all its threads • OS never trust a process, but trusts hardware • Hypervisor never trust a VM, but trust hardware • The TCB in cloud is very big, explained later • Cloud operators themselves may be potential adversaries

Why is hypervisor/OS not trustable The TCB of hypervisor contains virtualization stack larger than 9 Million LOCs TCB Size of Xen System growing ■Xen2.0 10000 ■Xen30 Contro vn Tools ■Xen4.0 5000 Kernel VMM Xen's TcB o= VMM TCB Kernel

Why is hypervisor/OS not trustable • The TCB of hypervisor • contains virtualization stack • larger than 9 Million LOCs • growing … 0 5000 10000 VMM Dom0 Kernel Tools TCB KLOCs TCB Size of Xen System Xen 2.0 Xen 3.0 Xen 4.0 VMM Xen’s TCB Control VM Tools Kernel Guest VM

Outline Cloud environment Security problems in cloud How to protect applications against Hypervisor/OS in cloud Intel SGX, protecting applications against OS SCONE(OSDI'16), using Intel SGX How to protect user data against applications in cloud yoan(OSDI'16), using Nacl (s&P09)and Intel SGX How to verify network security in cloud TenantGuard(NDSS'17), verifying network isolation in cloud

Outline • Cloud environment & Security problems in cloud • How to protect applications against Hypervisor/OS in cloud • Intel SGX, protecting applications against OS • SCONE (OSDI’16), using Intel SGX • How to protect user data against applications in cloud • Ryoan (OSDI’16), using NaCl (S&P’09) and Intel SGX • How to verify network security in cloud • TenantGuard (NDSS’17)， verifying network isolation in cloud

How to protect applications against Hypervisor/Os in cloud Dilemma: Hypervisor/os has privileges and absolute control over computing resources Solution: using hardware to fight against OS Intel Software Guard eXtensions, SGX

How to protect applications against Hypervisor/OS in cloud • Dilemma: Hypervisor/OS has privileges and absolute control over computing resources. • Solution: using hardware to fight against OS. • Intel Software Guard eXtensions, SGX

Intel SG×, key idea New processor mode: enclave untrusted trusted Execute App can create a HW enforced trusted Return environment enclave. not accessibl EENTER for OS prⅳ ileged access from App only trust Intel and SGX OS,ⅥMM,SMM forbidden Implementation

Intel SGX, key idea • New processor mode: enclave • App can create a HW enforced trusted environment, enclave, not accessible for OS • App only trust Intel and SGX implementation

Intel SGX, runtime example ① Application 1. App is built with trusted and untrusted parts Untrusted Part Trusted Part of App of App Call Gate 2. App create enclave, enclave is a memory ared protected by CPU, and OS is blind for it, privileged Process software cannot access it 2 Create Enclave 3. App call trusted part, and run in protected security environment CallTrusted0 Return (5 4. Data in enclave is plaintext, cannot be accessed from outside, and will be encrypted once move out enclave Privileged system Code 5. App finished task in enclave and return OS, VMM, BIOS, SMM App runs in common environment

Intel SGX, runtime example 1. App is built with trusted and untrusted parts 2. App create enclave, enclave is a memory area protected by CPU, and OS is blind for it, privileged software cannot access it. 3. App call trusted part, and run in protected security environment 4. Data in enclave is plaintext, cannot be accessed from outside, and will be encrypted once move out enclave 5. App finished task in enclave and return 6. App runs in common environment