dynamic integrity measurement and attestation: towards defense against return-oriented programming...

RuhR-University Bochum System Security Lab

Dynamic Integrity Measurement and Attestation: Towards Defense Against Return-Oriented Programming Attacks

Lucas Davi, Ahmad-Reza Sadeghi, Marcel Winandy

Ruhr-University Bochum, Germany

ACM STC 2009 – 4th Annual Workshop on Scalable Trusted ComputingChicago, Illinois, USA – November 13, 2009

2009-11-13DynIMA: Towards Defense Against Return-Oriented Programming 2

RuhR-University Bochum

Marcel Winandy

System Security Lab

Introduction

● Return-Oriented Programming (ROP) Attacks– Generalization of “return-into-libc” attacks

– Change program behavior without code injection

– Instead, use existing code● NX bit does'nt help!

● Discovered for Intel CISC (CCS 2007), and generalized to RISC architecture (CCS 2008)



Marcel Winandy

System Security Lab

ROP Attack



Marcel Winandy

System Security Lab

How does ROP work?

● Assumption: attacker controls the stack● Stack is overwritten with return addresses



Marcel Winandy

System Security Lab

Properties of ROP

● Points to the middle of functions● Typically small instruction sequences (gadgets)● Creates unintended instructions sequences● Example:

b8 13 00 00 00 mov $0x13,%eaxe9 c3 f8 ff ff jmp 3aae9



Marcel Winandy

System Security Lab

Properties of ROP

● Points in the middle of functions● Typically small instruction sequences (gadgets)● Creates unintended instructions sequences● Example:




Marcel Winandy

System Security Lab

Properties of ROP

● Points in the middle of functions● Typically small instruction sequences (gadgets)● Creates unintended instructions sequences● Example:


00 00 add %al,(%eax)00 e9 add %ch,%clc3 ret

Code is interpreted differently!



Marcel Winandy

System Security Lab

Our Proposal

● DynIMA: Dynamic Integrity Measurement and Attestion

– Bridge gap between load-time attestation and runtime integrity monitoring

– Support for wide-range of programs (e.g., no source code available)

– Our focus: detection of ROP attacks

● Main idea: include runtime checks via code instrumentation before loading programs



Marcel Winandy

System Security Lab

DynIMA Architecture



Marcel Winandy

System Security Lab

Tracking Instrumentation

● We examine two approaches– Taint Tracking

– Dynamic Tracing



Marcel Winandy

System Security Lab

Taint Tracking

● Dynamic taint analysis marks untrusted data as tainted and tracks its propagation

● Terminates program if tainted data is misused(e.g. as a pointer)



Marcel Winandy

System Security Lab

Using Taint Tracking to Detect ROP

● Idea: count instructions between two rets and raise alert if less or equal 5 instructions

– Observation: ROP gadgets are small (2 – 5)

– We were able to detect ROP attacks

– But: does this work in general?● False positives / false negatives



Marcel Winandy

System Security Lab

Dynamic Tracing

● Instrument code on-the-fly● Tracing code exists only if probes are activated

– Seems to be more flexible and faster

● DTrace (available on OpenSolaris, Mac OS X)– Code instrumentation and probe points

configured via D programming language



Marcel Winandy

System Security Lab

Using DTrace

● Idea: Detect whether functions are called from beginning or in the middle

● D program:



Marcel Winandy

System Security Lab

Using DTrace

● Idea: Detect whether functions are called from beginning or in the middle

● D program:

● However: can only detect intended returns



Marcel Winandy

System Security Lab

Some Recent Results

● The underlying instrumentation tool of taint analysis is faster and more powerful than DTrace: PIN

● We now use PIN directly:– On function call: memorize valid ret address

– Check every instruction if it is a ret

– Compare current ret if valid address (in list)



Marcel Winandy

System Security Lab

Performance of Detection with PIN

● First results:

gzip: w/o Pin: 16,49s with ROP-Detect: 24,51sbzip2: w/o Pin: 157,72s with ROP-Detect: 173,43sbunzip2: w/o Pin: 63,19s with ROP-Detect: 73,98ssha1sum: w/o Pin: 3,18s with ROP-Detect: 6,77s

● Overhead of ROP-Detect instrumentation:

gzip: 48,64%bzip2: 9,96%bunzip2: 17,08 %sha1sum: 112,89 %



Marcel Winandy

System Security Lab

Conclusion

● Return-Oriented Programming attacks can change runtime program behavior without code injection

● Good solution would be:

– Do your coding right (no buffer overflows, etc.)

– CPU modification to protect return address stack

– However, not to be expected on PCs soon

● Dynamic instrumentation might help to detect ROP attacks

● Future work:

– Analyze ROP detection capability

– Improve performance



Marcel Winandy

System Security Lab

Questions?

Marcel WinandyRuhr-University Bochum

[email protected]

mailto:[email protected]

dynamic integrity measurement and attestation: towards defense against return-oriented programming...

Documents

listmarcel winandy dynima

programsmarcel winandy

rop gadgets

rop idea

rop work

code instrumentation

middle of functions

taint tracking