DDoS Trojan attacks

Have you encountered with DDoS Trojan attack?

It’s a familiar issue to all SysAdmins, when we work on DDoS attack. Normally, the top command shows a suspicious process with a random name like, Xdrgwdjd, jjiiyaykzg etc or some system commands like ls, ifconfig, pwd, ping, awk, telnet etc.

When we kill that task another random process is being generated immediately.

Steps to fixing the attack :
———————

1) List the files under hourly cron. If you can see any .sh file, please open it.

root@vps-# ls -la /etc/cron.hourly/

++++++++++
# ls /etc/cron.hourly/
freshclam gcc.sh
++++++++++

2) If the .sh file is showing similar data as shown below, then it’s a Virus program!!

root@vps-# cat /etc/cron.hourly/gcc.sh

++++++++++
cat /etc/cron.hourly/gcc.sh
#! / Bin / sh
PATH = / bin: / sbin: / usr / bin: / usr / sbin: / usr / local / bin: / usr / local / sbin: / usr / X11R6 / bin
for i in `cat / proc / net / dev | grep: | awk -F: {‘print $ 1’}`; do ifconfig $ i up & done
cp /lib/libudev.so /lib/libudev.so.6
/lib/libudev.so.6
++++++++++

3) Now, please don’t be hurry! Stay calm and easy

# Do not delete gcc.sh or do not remove the crontab. If you do delete or remove it, then another process will generate immediately.

# You can either remove the culprit script or disable it. [ I prefer to disable it to show the proof to the customer ]

root@vps-# rm -f /etc/cron.hourly/gcc.sh;

OR

root@vps- # chmod 0 /etc/cron.hourly/gcc.sh; chattr +ia /etc/cron.hourly/gcc.sh; chattr + i /etc/crontab

4) Use top command to view virus or malicious file ( Eg :”mtyxkeaofa” ) PID is 16621, do not directly kill the program, otherwise it will again produce, but to stop its operation use the below command.

———————————-
root@vps- # kill -STOP 16621

# Delete files within /etc/init.d. or disable it [ I prefer to disable it to show the proof to the customer ]

root@vps-# find /etc -name '* mtyxkeaofa *' | xargs rm -f

OR

chmod 0 /usr/bin/mtyxkeaofa;
chmod 0 /etc/init.d/mtyxkeaofa;
chattr +ia /usr/bin/mtyxkeaofa;
chattr +ia /etc/init.d/mtyxkeaofa;

———————————-

6) Delete /usr/bin inside archives.

root@vps-# rm -f /usr/bin/mtyxkeaofa;

7) Check /usr/bin archives recent changes, the virus can also be deleted if the other suspect is the same directory.

root@vps-# ls -lt /usr/bin | head

8) Now kill the malicious program, it will not produce.

root@vps-# pkill mtyxkeaofa

9) Remove the virus body.

root@vps-# rm -f /lib/libudev.so

This trojan is also know as Chinese Chicken Multiplatform DoS botnets Trojan, Unix – Trojan.DDoS_XOR-1, Embedded rootkit,

Note :

~ If you are unable to find .sh file, you may please install ClamAV, RKHunter and check logs/report to find the suspicious/malicious

Isaac Adams-Hands

Full Stack Developer, Digital Marketer, and InfoSec enthusiast. He received his Bachelor’s Degree from the University of Western Sydney and his Business Diploma from Georgian College before joining various marketing positions in search portals, e-commerce, higher education, and addiction recovery services.

Follow @ twitter

Related posts

Remove a repository in source list using terminal

List You can remove the repository from the sources list using terminal. Find First you need to find your lists: sudo ls /etc/apt/sources.list.d Command Look for your desire PPA here and then remove the PPA using the following command: sudo rm -i /etc/apt/sources.list.d/PPA_Name.list

Force SSL on a WordPress

I’ve noticed that a .htaccess redirect works from the root folder down, but if you access the website from an old link you won’t be forced to HTTPS. Updating the WP URL structure does not help The Redirect This will work to force the redirect: If you are running WordPress in a sub folder, the… Read More