Table of Contents

System Forensics, Investigation, and Response Day 1-3

Day 2

Forensic Methodology Illustrated

Network Forensics..9

If there is suspician of activity, install a wiretap. Since you are protecting your network, there is legal precedent to use a wiretap. There must be “probable cause.”

Law enforcement, however, must have a supena.

Hackers will start out doing a

whois

lookup which gives information about primary network, mail exchange leading to internet cache, newsgroups, administrators asking questions leading to OS type, firewalls, etc.

packet 1776 has ftp data string. Filter on that.

tcp port == 24 shows putty

Linux Compromise: Forensic Verification..13

Helix..22

Set up forensics workstation to receive data via netcat

cd /images/unixforensics
nc -l -p 31337 > vmware_memory_dump

Use the programs from the cd. Memdump output should be sent via netcat (nc).

mount /dev/cdrom
cd /mnt/cdrom/Static-Binaries/linux_x86
./memdump | ./nc -vv 192.168.2.1 31337  

Output can be sent via netcat (nc), just set up listener on forensics workstation.

./uptime
./uname -a
./date
./fdisk -l
./mount
./netstat -anp
./lsof -n
./ls -lit

on forensics workstation:

cd /images/unixforensics
nc -vv -l -p 31337 > vmware_bodyfile/mac

on hacked machine:

mount /dev/cdrom
cd /mnt/cdrom/Static-Binaries/linux_x86
./mac-robber / | ./nc -vv 192.168.2.2 31337  

on forensics workstation:

cd /images/unixforensics
mactime -b vmware_bodyfile.mac > timeline-vmware.txt
less timeline-vmware.txt
  * MACtime Evidence..46
  * Volitile Information..47
  * Creating a Timeline..48
  * Creating your First Timeline..51
  * **mac-robber** Usage..52
  * **mactime**..53
  * Searching the file system [timeline]..57

commands hacker initially used

w
last
add user jack 
changed password to jack -checks password sc
secure copy rootkit
netstat 
top 
ps
creates /usr/sbin/mkxfs
creates /dev/ida/.. /sl2
/dev/ida/.drag-on

commonly trojanized files

these files look odd because the c time is only modified

ifconfig
ps
netstat
top

files with just a time have been accessed or executed.

logclear
linsniffer
.drag-on
..(space)

The modification times indicate that the innodes themselves werer changed (likely indicating that the files were decompressed). The c time shows that the files themselves were modified, which typically hpapens during installation.

lsof and netstat

set up nc listener

./lsof -n | ./nc 192.168.2.2 31337
./netstat -nap | ./nc 192.168.2.2 31337

lsof is a process list of open files on the system listing even deleted files that are still in use.

mkxsf is probably a trojanized ssh

inodes are sequential on a newly installed system.

./ls -lit /usr/bin | ./sort | ./less

directories to look at are /usr/bin, /usr/sbin, /sbin

To look at all files:

./ls -litR

if files are modified, they will have sequential inode allocations also. Look for very high or vary low numbers

Evidence Integrity..70

md5sum

./md5deep -r / | ./nc 192.168.2.2 31337 -w 3
  * National Software Reference Library..76

Forensic Imaging..77

dd if=INFILE of=OUTFILE

    bs= block size
    count=N
    skip=N
    conv=noerror,sync

ddfcl if=INFILE of=OUTFILE

    hashwindow=0 (entire machine)
    hashlog=drive.md5.txt

Host Protected Area

disk_stat /dev/hdb

removal (temporary)

disk_reset /dev/hdb

Before imaging nc these commands

mount
fdisk -l

On Forensics workstation:

cd /images/unixforensics
nc -l -p 31337 > vmware_dev_sda.img
md5sum vmware_dev_sda.img

On hacked machine:

mount /dev/cdrom /mnt/cdrom
cd /mnt/cdrom/Static_Binaries/linux_x86
fdisk -l
mount
./ddfcl if=/dev/sda hashwindow=0 | ./nc 129.168.2.2 31337

mmls disk1.dd if mmls cannot determine the type, try

mmls -t dos disk1.dd
dd if=disk1.dd bs=512 skip=62 count 1028097 of=part1.dd

the first extened partition is numbered 5 and then not from there on.

do not normally extract extended partitions; they are just boundaries.

the first 512 bytes contains the MBR. At byte 446 is the start of the partition table. Each entry is 16 bytes long. The last 8 bytes are useful. The last four are the length of the partition and the four before that are the offset. Don't forget to add 63 for the partition boundary(?).

mount root then mount the other partitions in there.

mount -t ext2 -o ro,loop,noexec vmware_dev_sda6.img /mnt/hack/unixforenseics_mount
mount -t ext2 -o ro,loop,noexec vmware_dev_sda1.img /mnt/hack/unixforenseics_mount/boot