Binary analysis with Radare2

Published: 2018-06-01
Last Updated: 2018-06-01 13:38:04 UTC
by Remco Verhoef (Version: 1)
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When I need to do a quick binary analysis, Radare2 is my framework of choice. Radare2 consists of multiple tools that will assist you during analysis:

r2 primary tool and used for static analysis and interactive debugging 
radiff2 unified binary diffing util, if you need to find out differences between versions of binaries, this tool is much of help.
rabin2 shows all kind of information on imports, sections headers etc and many different file formats
rax2 mathematical expression evaluator for all kind of conversions
ragg2 compile programs written in a simple high-level language into tiny binaries
rafind2 find byte patterns in files
rasm2 command line assembler and disassembler tool for multiple architectures
rahash2 supports a large number of hashing algorithms and functions on strings and files
rarun2 launcher for running programs in different environments with options for scripting and redirecting in- and output,
cutter Qt based Gui for Radare2 

Radare2 runs on many platforms, supports local native and remote debugging, many architectures, advanced scripting (python, javascript, go, etc), patching, code (block) emulation and analysis. Each of the tools deserves an individual post, but I'll highlight a few features which I use often. 

Converting and evaluating expressions using rax2, converting test into its hex value.

$ rax2 -S test

Generating hashes for 38 algorithms at once, using rahash2.

$ rahash2 -a all ./traur.bin
./traur.bin: 0x00000000-0x000373ff md5: edccfe5ef48de6b0f3bbf53cc1012533
Upload.exe: 0x00000000-0x0007d8cf sha1: 6e24eb2ad12990b617b2287aedd57ba5686a85f6
Upload.exe: 0x00000000-0x0007d8cf sha256: eb9553ddb141d5281b49dac4b50a6f626902c4e14dc3532fafb737f85e667915
Upload.exe: 0x00000000-0x0007d8cf sha384: 911dc5810ecf6e8c5fc77f7b05f25ef74e4e276589675ad8c7b2c90d04af25321a4ef58f33798f976ba87b6194d6dc08
Upload.exe: 0x00000000-0x0007d8cf sha512: cc5d1907c897d46b77dda8fb44da6585147079402ad5d3f36a577f6a6e83aa5a2d02eef7a52e38319a4c56d29abe518f9b7a7ecfd8d2bcd70a376790177d97e6
Upload.exe: 0x00000000-0x0007d8cf md4: 387c58ff2ac57565706e9c1bd0543578
Upload.exe: 0x00000000-0x0007d8cf xor: 74


A quick assessment of a binary using rabin2:

$ rabin2 -I ./Upload.exe
arch     x86
binsz    514256
bintype  pe
bits     32
canary   false
class    PE32
cmp.csum 0x000894e8
compiled Fri Apr 16 07:47:33 2010
crypto   false
endian   little
havecode true
hdr.csum 0x00000000
linenum  false
lsyms    false
machine  i386
maxopsz  16
minopsz  1
nx       false
os       windows
overlay  true
pcalign  0
pic      false
relocs   true
signed   false
static   false
stripped true
subsys   Windows GUI
va       true


Extract string section information using rabin2:

$ rabin2 -z ./Upload.exe
000 0x00044c0a 0x004bb20a   5  12 (.rsrc) utf16le SOUND
001 0x00044c16 0x004bb216   6  14 (.rsrc) utf16le FINISH
002 0x00044c68 0x004bb268   4   5 (.rsrc) ascii }}}K

Extract imports using rabin2:

$ rabin2 -i ./Upload.exe
   1 0x004c37ac    NONE    FUNC KERNEL32.DLL_LoadLibraryA
   2 0x004c37b0    NONE    FUNC KERNEL32.DLL_GetProcAddress
   3 0x004c37b4    NONE    FUNC KERNEL32.DLL_VirtualProtect
   4 0x004c37b8    NONE    FUNC KERNEL32.DLL_VirtualAlloc
   5 0x004c37bc    NONE    FUNC KERNEL32.DLL_VirtualFree


Disassembly of entry0 using r2:

$ r2 ./Upload.exe
 -- Can you stand on your head?
[0x004ba3c0]> aaaa
[x] Analyze all flags starting with sym. and entry0 (aa)
[x] Analyze function calls (aac)
[x] Analyze len bytes of instructions for references (aar)
[x] Emulate code to find computed references (aae)
[x] Analyze consecutive function (aat)
[x] Constructing a function name for fcn.* and sym.func.* functions (aan)
[x] Type matching analysis for all functions (afta)
[0x004ba3c0]> pd
            ;-- eip:
/ (fcn) entry0 436
|   entry0 ();
|           0x004ba3c0      60             pushal
|           0x004ba3c1      be00604700     mov esi, 0x476000           ; section.UPX1
|           0x004ba3c6      8dbe00b0f8ff   lea edi, [esi - 0x75000]
|           0x004ba3cc      57             push edi
|       ,=< 0x004ba3cd      eb0b           jmp 0x4ba3da
        |   0x004ba3cf      90             nop
|       |   ; CODE XREF from 0x004ba3e1 (entry0)


Find the differences between two binaries using radiff2.

$ radiff2 -g main /bin/true /bin/false | xdot -

Cutter is the Qt based GUI of Radare2.

When you want to get started, it is being advised to use Radare2 from Docker or source. 



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