The CISO has received a bulletin from law enforcementauthorities warning that the enterprise may be...

Step 1: Understand the Objective

Objective:

Identify thedomain name(s)that werecontactedbetween:

12:10 AM to 12:12 AM on August 17, 2024

Source of information:

CCOA Threat Bulletin.pdf

File location:

~/Desktop/CCOA Threat Bulletin.pdf

Step 2: Prepare for Investigation

2.1: Ensure Access to the File

Check if the PDF exists:

ls ~/Desktop | grep "CCOA Threat Bulletin.pdf"

Open the file to inspect:

xdg-open ~/Desktop/CCOA\ Threat\ Bulletin.pdf

Alternatively, convert to plain text for easier analysis:

pdftotext ~/Desktop/CCOA\ Threat\ Bulletin.pdf ~/Desktop/threat_bulletin.txt

cat ~/Desktop/threat_bulletin.txt

2.2: Analyze the Content

Look for domain names listed in the bulletin.

Make note ofany domainsorURLsmentioned as IoCs (Indicators of Compromise).

Example:

suspicious-domain.com

malicious-actor.net

threat-site.xyz

Step 3: Locate Network Logs

3.1: Find the Logs Directory

The logs could be located in one of the following directories:

/var/log/

/home/administrator/hids/logs/

/var/log/httpd/

/var/log/nginx/

Navigate to the likely directory:

cd /var/log/

ls -l

Identify relevant network or DNS logs:

ls -l | grep -E "dns|network|http|nginx"

Step 4: Search Logs for Domain Contacts

4.1: Use the Grep Command to Filter Relevant Timeframe

Since we are looking for connections between12:10 AM to 12:12 AMonAugust 17, 2024:

grep "2024-08-17 00:1[0-2]" /var/log/dns.log

Explanation:

grep "2024-08-17 00:1[0-2]": Matches timestamps between00:10and00:12.

Replace dns.log with the actual log file name, if different.

4.2: Further Filter for Domain Names

To specifically filter out the domains listed in the bulletin:

grep -E "(suspicious-domain.com|malicious-actor.net|threat-site.xyz)" /var/log/dns.log

If the logs are in another file, adjust the file path:

grep -E "(suspicious-domain.com|malicious-actor.net|threat-site.xyz)" /var/log/nginx/access.log

Step 5: Correlate Domains and Timeframe

5.1: Extract and Format Relevant Results

Combine the commands to get time-specific domain hits:

grep "2024-08-17 00:1[0-2]" /var/log/dns.log | grep -E "(suspicious-domain.com|malicious-actor.net|threat-site.xyz)"

Sample Output:

2024-08-17 00:11:32 suspicious-domain.com accessed by 192.168.1.50

2024-08-17 00:12:01 malicious-actor.net accessed by 192.168.1.75

Interpretation:

The command revealswhich domain(s)were contacted during the specified time.

Step 6: Verification and Documentation

6.1: Verify Domain Matches

Cross-check the domains in the log output against those listed in theCCOA Threat Bulletin.pdf.

Ensure that the time matches the specified range.

6.2: Save the Results for Reporting

Save the output to a file:

grep "2024-08-17 00:1[0-2]" /var/log/dns.log | grep -E "(suspicious-domain.com|malicious-actor.net|threat-site.xyz)" > ~/Desktop/domain_hits.txt

Review the saved file:

cat ~/Desktop/domain_hits.txt

Step 7: Report the Findings

Final Answer:

Domain(s) Contacted:

suspicious-domain.com

malicious-actor.net

Time of Contact:

Between 12:10 AM to 12:12 AM on August 17, 2024

Reasoning:

Matched thelog timestampsanddomain nameswith the threat bulletin.

Step 8: Recommendations:

Immediate Block:

Add the identified domains to theblockliston firewalls and intrusion detection systems.

Monitor for Further Activity:

Keep monitoring logs for any further connection attempts to the same domains.

Perform IOC Scanning:

Check hosts that communicated with these domains for possible compromise.

Incident Report:

Document the findings and mitigation actions in theincident response log.