BAPBinary Analysis Platform

A Modern Toolkit For Binary Analysis and Reverse Engineering

http://bap.ece.cmu.edu

What is BAP?

• BAP is a framework for modular analysis of binary programs–an extensible set of interoperable tools and

analyses–a set of high-quality libraries

Why BAP?

• BAP is for writing analyses that are–Reproducible–Scalable–Cross-architectural –Practical

• The “write once run many” approach

What BAP is not?

• Not an interactive RE tool• Not a CTF tool• Not (only) for academic purpose• Not (only) for sound analysis• Not (only) for static analysis• Not dead

Why not BAP?

• No OCaml programmers–Limited support for Python–C-bindings–Rust bindings–Facebook Reason, Flow, Javascript

• No Java, C#, or source (script) code analysis• Not all architectures are supported• No support for floating points

BAP Architecture (key points)

• Translates a program to BIL• Extensible Plugin Architecture• Different kinds of plugins:

–Analysis–Disassemblers–Architecture support–ABI, OS, Language support– ...

BAP Architecture (pipeline)Binary

Loader

Image

Disassembler

CFG

Reconstructor

Program ABI API ... p1 ...

BAP Architecture (pipeline)Binary

Loader

Image

Disassembler

CFG

Reconstructor

Program ABI API ... p1 ...

BAP Architecture (pipeline)Binary

Loader

Image

Disassembler

CFG

Reconstructor

Program ABI API ... p1 ... pN dump

Batteries Included

• WUR - warn unused results• Beagle - string deobfuscator• Primus - emulation and microexecution• Saluki - fast policy checker• Static and Dynamic Taint Analysis• UAF, ROP, strings, callsites, …

BAP in action

Much more on tomorrow’s workshop

$ bap arm-linux-gnueabi-echo -dasm | grep main -A16

00008534: <main>

00008534:

00008534: f0 4d 2d e9 push {r4, r5, r6, r7, r8, r10, r11, lr}

00008538: 1c b0 8d e2 add r11, sp, #0x1c

0000853c: 18 d0 4d e2 sub sp, sp, #0x18

00008540: 30 00 0b e5 str r0, [r11, #-48]

00008544: 34 10 0b e5 str r1, [r11, #-52]

00008548: 0d 30 a0 e1 mov r3, sp

0000854c: 03 a0 a0 e1 mov r10, r3

00008550: 30 30 1b e5 ldr r3, [r11, #-48]

00008554: 01 20 83 e2 add r2, r3, #0x1

00008558: 01 30 42 e2 sub r3, r2, #0x1

0000855c: 24 30 0b e5 str r3, [r11, #-36]

00008560: 02 10 a0 e1 mov r1, r2

00008564: 01 30 a0 e1 mov r3, r1

00008568: 00 40 a0 e3 mov r4, #0x0

Disassembling

$ bap arm-linux-gnueabi-echo -d | grep main -A16

000000ca: sub main(main_argc, main_argv, main_result)

00000164: main_argc :: in u32 = R0

00000165: main_argv :: in out u32 = R1

00000166: main_result :: out u32 = R0

00000050:

00000051: v618 := SP

00000052: mem := mem with [v618 - 0x4:32, el]:u32 <- LR

00000053: mem := mem with [v618 - 0x8:32, el]:u32 <- R11

00000054: mem := mem with [v618 - 0xC:32, el]:u32 <- R10

00000055: mem := mem with [v618 - 0x10:32, el]:u32 <- R8

00000056: mem := mem with [v618 - 0x14:32, el]:u32 <- R7

00000057: mem := mem with [v618 - 0x18:32, el]:u32 <- R6

00000058: mem := mem with [v618 - 0x1C:32, el]:u32 <- R5

00000059: mem := mem with [v618 - 0x20:32, el]:u32 <- R4

0000005a: SP := SP - 0x20:32

0000005b: R11 := SP + 0x1C:32

Displaying IR

Displaying Cfg$ bap arm-linux-gnueabi-echo -dcfg --print-symbol=main | xdot

open Core_kernel.Std

open Bap.Std

let counter = object

inherit [int * int] Term.visitor

method! enter_term _ _ (jmps,total) = jmps,total+1

method! enter_jmp _ (jmps,total) = jmps+1,total

end

let main proj =

let jmps,total = counter#run (Project.program proj) (0,0) in

printf "ratio = %d/%d = %g\n" jmps total (float jmps /. float total)

let () = Project.register_pass' main

Write a plugin

$ bapbuild jmp.plugin

$ bapbundle install jmp.plugin

$ bap /bin/true --pass=jmp

ratio = 974/7514 = 0.129625

Building and running

import bap

from bap.adt import Visitor

class Counter(Visitor) :

def __init__(self):

self.jmps = 0

self.total = 0

def enter_Jmp(self,jmp):

self.jmps += 1

def enter_Term(self,t):

self.total += 1

proj = bap.run('/bin/true')

count = Counter()

count.run(proj.program)

print("ratio = {0}/{1} = {2}".format(count.jmps, count.total,

count.jmps/float(count.total)))

Same in Python

BAP Workshop

• Wednesday, September 27 (tomorrow)• Time: 9:00 - 11:30• Location: GHC 6115 (here)• Learn how to use BAP• Learn how to extend BAP using

–OCaml–Python

Be prepared!

• Either install BAP from opam manually• Or use Vagrant to install a provisioned VM:$ wget http://tiny.cc/Vagrantfile

$ vagrant up$ vagrant ssh$ bap --version