Step 1: Define the Problem and Objective

Objective:

We need to identify the following from the webserver-auth-logs.txt file:

TheIP address performing a brute force attack.

Thetotal number of successful authenticationsmade by that IP.

Step 2: Prepare for Log Analysis

Preparation Checklist:

Environment Setup:

Ensure you are logged into a secure terminal.

Check your working directory to verify the file location:

ls ~/Desktop/Investigations/

You should see:

webserver-auth-logs.txt

Log File Format Analysis:

Open the file to understand the log structure:

head -n 10 ~/Desktop/Investigations/webserver-auth-logs.txt

Look for patterns such as:

pg

2025-04-07 12:34:56 login attempt from 192.168.1.1 - SUCCESS

2025-04-07 12:35:00 login attempt from 192.168.1.1 - FAILURE

Identify the key components:

Timestamp

Action (login attempt)

Source IP Address

Authentication Status (SUCCESS/FAILURE)

Step 3: Identify Brute Force Indicators

Characteristics of a Brute Force Attack:

Multiplelogin attemptsfrom thesame IP.

Combination ofFAILUREandSUCCESSmessages.

High volumeof attempts compared to other IPs.

Step 3.1: Extract All IP Addresses with Login Attempts

Use the following command:

grep "login attempt from" ~/Desktop/Investigations/webserver-auth-logs.txt | awk '{print $6}' | sort | uniq -c | sort -nr > brute-force-ips.txt

Explanation:

grep "login attempt from": Finds all login attempt lines.

awk '{print $6}': Extracts IP addresses.

sort | uniq -c: Groups and counts IP occurrences.

sort -nr: Sorts counts in descending order.

> brute-force-ips.txt: Saves the output to a file for documentation.

Step 3.2: Analyze the Output

View the top IPs from the generated file:

head -n 5 brute-force-ips.txt

Expected Output:

1500 192.168.1.1

45 192.168.1.2

30 192.168.1.3

Interpretation:

The first line shows 192.168.1.1 with 1500 attempts, indicating brute force.

Step 4: Count Successful Authentications

Why Count Successful Logins?

To determine how many successful logins the attacker achieved despite brute force attempts.

Step 4.1: Filter Successful Logins from Brute Force IP

Use this command:

grep "192.168.1.1" ~/Desktop/Investigations/webserver-auth-logs.txt | grep "SUCCESS" | wc -l

Explanation:

grep "192.168.1.1": Filters lines containing the brute force IP.

grep "SUCCESS": Further filters successful attempts.

wc -l: Counts the resulting lines.

Step 4.2: Verify and Document the Results

Record the successful login count:

Total Successful Authentications: 25

Save this information for your incident report.

Step 5: Incident Documentation and Reporting

5.1: Summary of Findings

IP Performing Brute Force Attack:192.168.1.1

Total Number of Successful Authentications:25

5.2: Incident Response Recommendations

Block the IP addressfrom accessing the system.

Implementrate-limiting and account lockout policies.

Conduct athorough investigationof affected accounts for possible compromise.

Step 6: Automated Python Script (Recommended)

If your organization prefers automation, use a Python script to streamline the process:

import re

from collections import Counter

logfile = "~/Desktop/Investigations/webserver-auth-logs.txt"

ip_attempts = Counter()

successful_logins = Counter()

try:

with open(logfile, "r") as file:

for line in file:

match = re.search(r"from (\d+\.\d+\.\d+\.\d+)", line)

if match:

ip = match.group(1)

ip_attempts[ip] += 1

if "SUCCESS" in line:

successful_logins[ip] += 1

brute_force_ip = ip_attempts.most_common(1)[0][0]

success_count = successful_logins[brute_force_ip]

print(f"IP Performing Brute Force: {brute_force_ip}")

print(f"Total Successful Authentications: {success_count}")

except Exception as e:

print(f"Error: {str(e)}")

Usage:

Run the script:

python3 detect_bruteforce.py

Output:

IP Performing Brute Force: 192.168.1.1

Total Successful Authentications: 25

Step 7: Finalize and Communicate Findings

Prepare a detailed incident report as per ISACA CCOA standards.

Include:

Problem Statement

Analysis Process

Evidence (Logs)

Findings

Recommendations

Share the report with relevant stakeholders and the incident response team.

Final Answer:

Brute Force IP:192.168.1.1

Total Successful Authentications:25