Blocking a known malicious actor

Install the Apache web server

Perform the following steps to install and configure an Apache web server.

1. Install the latest Visual C++ Redistributable package.

2. Download the Apache web server Win64 ZIP installation file. This is an already compiled binary for Windows operating systems.

3. Unzip the contents of the Apache web server zip file and copy the extracted Apache24 folder to the C: directory.

4. Navigate to the C:\Apache24\bin\ folder and run the following command in a PowerShell terminal with administrator privileges:

   > .\httpd.exe
   

   The first time you run the Apache binary a Windows Defender Firewall pops up.

5. Click on Allow Access. This allows the Apache HTTP server to communicate on your private or public networks depending on your network setting. It creates an inbound rule in your firewall to allow incoming traffic on port 80.

6. Open http://<WINDOWS_IP> in a browser to view the Apache landing page and verify the installation. Also, verify that this URL can be reached from the attacker endpoint.

Configure the Wazuh agent

Perform the steps below to configure the Wazuh agent to monitor Apache web server logs.

1. Add the following to C:\Program Files (x86)\ossec-agent\ossec.conf to configure the Wazuh agent and monitor the Apache access logs:

   <localfile>
     <log_format>syslog</log_format>
     <location>C:\Apache24\logs\access.log</location>
   </localfile>
   

2. Restart the Wazuh agent in a PowerShell terminal with administrator privileges to apply the changes:

   > Restart-Service -Name wazuh
   

Download the utilities and configure the CDB list

1. Install the wget utility to download the necessary artifacts using the command line interface:

   $ sudo yum update && sudo yum install -y wget
   

2. Download the Alienvault IP reputation database:

   $ sudo wget https://iplists.firehol.org/files/alienvault_reputation.ipset -O /var/ossec/etc/lists/alienvault_reputation.ipset
   

3. Append the IP address of the attacker endpoint to the IP reputation database. Replace <ATTACKER_IP> with the RHEL IP address in the command below:

   $ sudo echo "<ATTACKER_IP>" >> /var/ossec/etc/lists/alienvault_reputation.ipset
   

4. Download a script to convert from the .ipset format to the .cdb list format:

   $ sudo wget https://wazuh.com/resources/iplist-to-cdblist.py -O /tmp/iplist-to-cdblist.py
   

5. Convert the alienvault_reputation.ipset file to a .cdb format using the previously downloaded script:

   $ sudo /var/ossec/framework/python/bin/python3 /tmp/iplist-to-cdblist.py /var/ossec/etc/lists/alienvault_reputation.ipset /var/ossec/etc/lists/blacklist-alienvault
   

6. Optional: Remove the alienvault_reputation.ipset file and the iplist-to-cdblist.py script, as they are no longer needed:

   $ sudo rm -rf /var/ossec/etc/lists/alienvault_reputation.ipset
   $ sudo rm -rf /tmp/iplist-to-cdblist.py
   

7. Assign the right permissions and ownership to the generated file:

   $ sudo chown wazuh:wazuh /var/ossec/etc/lists/blacklist-alienvault
   

Configure the Active Response module to block the malicious IP address

1. Add a custom rule to trigger a Wazuh active response script. Do this in the Wazuh server /var/ossec/etc/rules/local_rules.xml custom ruleset file:

   <group name="attack,">
     <rule id="100100" level="10">
       <if_group>web|attack|attacks</if_group>
       <list field="srcip" lookup="address_match_key">etc/lists/blacklist-alienvault</list>
       <description>IP address found in AlienVault reputation database.</description>
     </rule>
   </group>
   

2. Edit the Wazuh server /var/ossec/etc/ossec.conf configuration file and add the etc/lists/blacklist-alienvault list to the <ruleset> section:

   <ossec_config>
     <ruleset>
       <!-- Default ruleset -->
       <decoder_dir>ruleset/decoders</decoder_dir>
       <rule_dir>ruleset/rules</rule_dir>
       <rule_exclude>0215-policy_rules.xml</rule_exclude>
       <list>etc/lists/audit-keys</list>
       <list>etc/lists/amazon/aws-eventnames</list>
       <list>etc/lists/security-eventchannel</list>
       <list>etc/lists/blacklist-alienvault</list>
   
       <!-- User-defined ruleset -->
       <decoder_dir>etc/decoders</decoder_dir>
       <rule_dir>etc/rules</rule_dir>
     </ruleset>
   
   </ossec_config>
   

3. Add the Active Response block to the Wazuh server /var/ossec/etc/ossec.conf file:

   For the Ubuntu endpoint

   The firewall-drop command integrates with the Ubuntu local iptables firewall and drops incoming network connection from the attacker endpoint for 60 seconds:

   <ossec_config>
     <active-response>
       <disabled>no</disabled>
       <command>firewall-drop</command>
       <location>local</location>
       <rules_id>100100</rules_id>
       <timeout>60</timeout>
     </active-response>
   </ossec_config>
   

   For the Windows endpoint

   The active response script uses the netsh command to block the attacker's IP address on the Windows endpoint. It runs for 60 seconds:

   <ossec_config>
     <active-response>
       <disabled>no</disabled>
       <command>netsh</command>
       <location>local</location>
       <rules_id>100100</rules_id>
       <timeout>60</timeout>
     </active-response>
   </ossec_config>
   

4. Restart the Wazuh manager to apply the changes:

   $ sudo systemctl restart wazuh-manager