Task 1: Preparation
Step 1.1 SSH into the Machine
SSH into the box with the credentials provided.
ssh <username>@<IP_address>
# Replace <username> and <IP_address> with the values given
Task 2: Initial Access
Question 1: Which programming language is the web application written in?
Navigate through the directories to find the application’s code.
cd /home/support/api_service
ls -la
Answer: Python
Question 2: What is the IP address that attacked the web server?
The web server uses NGINX, so we can check its logs for suspicious activity.
cd /var/log/nginx
tail -n 10 access.log.1
Look for commands like whoami, pwd, or id, which indicate enumeration attempts by an attacker.
Answer: 149.34.244.142
Question 3: Which vulnerability was found and exploited in the API service?
Inspect the api.py source code for vulnerabilities, particularly around command handling.
cat /home/support/api_service/api.py
Answer: OS command injection
Question 4: Which file contained the credentials used to privilege escalate to root?
Examine the configuration file for any stored credentials.
cat /home/dev/apiservice/src/config.py
Answer: /home/dev/apiservice/src/config.py
Question 5: What file did the hacker drop and execute to persist on the server?
Check the bash history to uncover any evidence of files dropped.
sudo su
cat /root/.bash_history
Answer: /tmp/rooter2
Question 6: Which service was used to host the “rooter2” malware?
In .bash_history, look for commands involving file uploads or downloads.
Answer: transfer.sh
Task 3: Further Actions
Question 7: Which two system files were infected to achieve cron persistence?
Check crontab and environment files for unauthorized entries.
cat /etc/crontab
cat /etc/environment
Answer: /etc/crontab, /etc/environment
Question 8: What is the C2 server IP address of the malicious actor?
Locate the IP address associated with the SYSTEMUPDATE variable in /etc/environment or other files identified in bash history.
Answer: 5.230.66.147
Question 9: What port is the backdoored bind bash shell listening on?
Use ps to check running processes for a netcat listener.
ps -aux | grep nc
Answer: 3578
Question 10: How does the bind shell persist across reboots?
Locate the systemd service created by the attacker.
grep -R "nc -l" /
Answer: systemd service
Question 11: What is the absolute path of the malicious service?
Find the absolute path from the output of the grep command above.
Answer: /etc/systemd/system/socket.service
Task 4: Even More Persistence
Question 12: Which port is blocked on the victim’s firewall?
Use iptables to examine the firewall configuration.
iptables -L
Answer: 3578
Question 13: How do the firewall rules persist across reboots?
Check the root user's bash configuration files for persistence mechanisms.
cat /root/.bashrc
Answer: /root/.bashrc
Question 14: How is the backdoored local Linux user named?
Inspect the /etc/passwd file for unusual user entries.
grep "/bin/bash" /etc/passwd
Answer: support
Question 15: Which privileged group was assigned to the user?
Use the groups command to list group memberships for the user.
groups support
Answer: sudo
Question 16: What is the strange word on one of the backdoored SSH keys?
View the authorized_keys file in the root user’s SSH directory.
cat /root/.ssh/authorized_keys
Answer: ntsvc
Question 17: Can you spot and name one more popular persistence method? Not a MITRE technique name.
Check for files with the SUID bit set.
find / -perm -u=s -type f 2>/dev/null
Answer: SUID binary
Question 18: What are the original and the backdoored binaries from question 6?
Verify the integrity of the suspected binary.
ls -l /usr/bin/clamav
dpkg --verify clamav
Answer: /usr/bin/bash, /usr/bin/clamav
Question 19: What technique was used to hide the backdoor creation date?
Identify timestamp modification.
Answer: Timestomping
Task 5: Final Target
Question 20: What file was dropped which contained gathered victim information?
Check root’s .bash_history for evidence of dropped files.
cat /root/.bash_history
Answer: /root/.dump.json
Question 21: According to the dropped dump, what is the server’s kernel version?
Decode and inspect .dump.json for details.
cat /root/.dump.json | base64 -d
Answer: 5.15.0–78-generic
Question 22: Which active internal IPs were found by the “rooter2” network scan?
Identify internal IPs from the dump.
Answer: 192.168.0.21,192.168.0.22
Question 23: How did the hacker find an exposed HTTP index on another internal IP?
Check the history for a network scan command.
grep -i "nc -zv" /root/.bash_history
Answer: nc -zv 192.168.0.22 1024-10000 2>&1 | grep -v failed
Question 24: What command was used to exfiltrate the CDE database from the internal IP?
Locate the wget command in the history.
grep "wget" /root/.bash_history
Answer: wget 192.168.0.22:8080/cde-backup.csv
Question 25: What is the most secret and precious string stored in the exfiltrated database?
Inspect the contents of the exfiltrated .review.csv file.
cat .review.csv | head -n 10
Answer: pwned{v3ry-secur3-cardh0ld3r-data-environm3nt}
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