Target: Red Hat Enterprise Linux Server release 7.6 (Maipo)
Tools:
1. SANS SIFT Workstation: https://digital-forensics.sans.org/community/downloads
2. Log2timeline
3. Aureport
4. Lnav: https://lnav.org/
5. Stat
6. Cat
7. Grep
8. Lastb
9. Last
10. Chrootkit
11. Rkhunter
12. Clamav
13. Lynis: https://cisofy.com/lynis/
Offline investigation
1. Mount the victim DD image on SIFT Workstation.
2. Antivirus scan with clamAV
1) Update ClamAV:
a. sudo systemctl stop clamav-freshclam.service
b. sudo freshclam
2) Scan the image: clamscan -r -i DIRECTORY
3. Rootkit scan with Chkrootkit
1) Install:
|
# apt-get update # apt install chkrootkit # chkrootkit -V |
2) Scan: # chkrootkit -r /mnt/ ; This will check all files under this specified directory.
4. Build timeline
1) sudo log2timeline.py victim.plaso /media/sansforensics/
2) sudo log2timeline.py -z America/Toronto victim.plaso /media/sansforensics/
3) search key word:
a. USER_PROCESS IP Address
b. User:
c. terminal=ssh res=success
5. aureport offline check:
1) Install: sudo apt install auditd
2) Load the offline logs: aureport --input
6. Check suspicious file info: stat filename
7. A few cat commands:
|
cat /var/log/secure-yyyymmdd | grep "authentication failure" | more cat secure- yyyymmdd | grep "user NOT in sudoers" cat secure- yyyymmdd | grep "failed - POSSIBLE BREAK-IN ATTEMPT" | more cat secure- yyyymmdd | grep "Accept" | more |
8. Show root user login history: lastb -f btmp-20201016 -Fadx root | more
9. Show login history: last -aiF -f wtmp
10. Check hosts file (if the attacker hijacks the DNS): sudo cat (mount drive)/etc/hosts
11. Check autoruns script: sudo cat (mount drive)/etc/fstab
12. Check cron job:
|
ls /etc/cron* cat /etc/crontab |
Online check
1. Import/convert DD image to VMware and take a snapshot.
2. Turn on the system.
3. Check cron job: cron -l; sudo cron -l
4. Check hosts file (if the attacker hijacks the DNS): sudo cat etc/hosts
5. Check autoruns script: sudo cat etc/fstab
6. Aureport commands:
|
aureport -au -i | more
aureport -au -i --success | more (To get authentication report for all the success attempts which was made.)
aureport -au -i --failed | more (To get authentication report for all the failed attempts which was made.)
aureport -l --success | more (To get success login information.)
aureport -l --failed | more (To get failed login information.)
aureport -l --success --summary -i | more (To get success login summary report for all the success attempts which was made.) |
7. Install and run chkrootkit
8. Install and run rkhunter.
9. Install and run clamAV
10. Install and run lynis
11. Install and run lnav.
Reference:
1. https://digital-forensics.sans.org/community/downloads
4. https://www.redhat.com/sysadmin/3-antimalware-solutions
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