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DLP examples

Blocking content with credit card numbers

When the objective is to block credit card numbers one of the important things to remember is that 2 filters will need to be used in the sensor.

In the default Credit-Card sensor, you will notice a few things.

• The Action is set to Log Only
• In the Files filter not all of the services are being examined.

If you wish to block as much content as possible with credit card numbers in it instead of just logging most the traffic that has it, the existing sensor will have to be edited.

1. Go to Security Profile > Data Leak Prevention

Some configurations will have a preconfigured Credit Card sensor where you can use the drop down menu to select Credit-Card. If your configuration doesn’t already have one create a new sensor.

2. Use the Create New icon to add a new sensor.
3. Create/edit the first filter. Use the following settings:

Filter

Filter	Messages
Filter option	Credit Card #

Examine the Following Services

Make sure all of the services are being examined.

Action

Set action to Block.

Select OK or Apply.

4. Create/edit the first filter. Use the following settings:

Filter

Filter	Files
Filter option	Credit Card #

Examine the Following Services

Make sure all of the services are being examined.

Action

Set action to Block.

Select OK or Apply

5. Edit the appropriate policies so that under Security Profiles, DLP is turned on and the Credit-Card sensor is selected.

Blocking emails larger than 15 MB and logging emails from 5 MB to 15 MB

Multiple filters will have to be used in this case and the order that they are used is important. Because there is no mechanism to move the filters within the sensor the order that they are added to the sensor is important.

1. Go to Security Profile > Data Leak Prevention.
2. Use the Create New icon to add a new sensor.
   Use the following values:

Name	large_emails
Comment	<optional>

Once the Sensor has been created, a new filter will need to be added.

3. Create the filter to block the emails over 15 MB. In the filters table select Create New.
   Use the following values:

Filter

Filter	Messages
Filter option	File Size >=
KB	15360 (1MB = 1024KB, 15 MB = 15 x 1024KB = 15360KB)

Examine the Following Services

Make sure all of the Email services are being examined.

Action

Set action to Block.

Select OK.

4. Create the filter to log emails between 5 MB and 10 MB. In the filters table select Create New.
   Use the following values

Filter

Filter	Messages
Filter option	File Size >=
KB	5120 (1MB = 1024KB, 5 MB = 5 x 1024KB = 5124 KB)

Examine the Following Services

Make sure all of the Email services are being examined.

Action

Set action to Block.

Select OK.

The reason that the block filter is placed first is because the filters are applied in sequence and once the traffic triggers a filter the action is applied and then the traffic is passed on to the next test. If the Log Only filter which checks for anything over 1MB is triggered this would include traffic over 15MB, so a 16 MB file would only be logged. In the described order, the 16 MB file will be blocked and the 3 MB file will be logged.

Selective blocking based on a finger print

The following is a fairly complex example but shows what can be done by combining various components in the correct configuration.

The company has a number of copyrighted documents that it does not want “escaping” to the Internet but it does want to be able to send those documents to the printers for turning into hardcopy.

The policies and procedures regarding this issue state that:

• Only members of the group Senior_Editors can send copyrighted material to the printers.
• Every member of the company by default is included in the group employees.
• Even permitted transmission of copyrighted material should be recorded.
• All of the printers IP addresses are in a group called approved_printers.
• There is a file share called copyrighted where any file that is copyrighted is required to have a copy stored.
• It doesn’t happen often but for legal reasons sometimes these files can be changed, but all versions of a file in this directory need to be secured.
• All network connections to the Internet must have Antivirus enabled using at least the default profile.
• The SSL/SSH Inspection profile used will be default.

It is assumed for the purposes of this example that:

• Any addresses or address groups have been created.
• User accounts and groups have been created.
• The account used by the FortiGate is fgtaccess.
• The copyrighted sensitivity level needs to be created.
• The copyrighted material is stored at \\192.168.27.50\books\copyrighted\

1. Add a new Sensitivity Level by running the following commands in the CLI

config dlp fp-sensitivity

edit copyrighted

end

 

2. Apply files to the fingerprint database

1. Go to Security Profiles > Advanced > DLP Fingerprint.
2. In the Document Sources section select Create New.
   Use the following field values:

Name	copyrighted_material
Server Type	Windows Share
Server Address	192.168.27.50
User Name	fgtaccess
Password	******
Path	books/copyrighted/
Filename Pattern	*.pdf
Sensitivity	copyrighted
Scan Periodically	enabled
<Frequency>	Daily, Hour: 2, Min: 0
Advanced
Fingerprint files in subdirectories	enabled
Remove fingerprints for deleted files	not enabled
Keep previous fingerprints for modified files	enabled

Two Sensors need to be created. One for blocking the transmission of copyrighted material and a second for allowing the passing of copyrighted material under specific circumstances.

3. Create the first DLP Sensor

• Go to Security Profile > Data Leak Prevention.
• Create a new sensor.
  Use the following field values:

Name	block_copyrighted
Comment	<optional>

• In the Filter table, select Create New.
  Use the following values
  
  Filter

Filter	Files
Filter option	File Finger Print
Finger print value from dropdown	“copyrighted”

Examine the Following Services

Make sure all of the services are being examined.

Action

From the drop down menu choose Block

4. Create the second DLP Sensor

• Go to Security Profile > Data Leak Prevention.
• Create a new sensor.
  Use the following field values:

Name	allow_copyrighted
Comment	<optional>

• In the Filter table, select Create New.
  Use the following values
  
  Filter

Filter	Files
Filter option	File Finger Print
Finger print value from dropdown	“copyrighted”

Examine the Following Services

Make sure all of the services are being examined.

Action

From the drop down menu choose Log Only

5. Create a policy to allow transmission of copyrighted material.

1. Go to Policy & Objects > Policy > IPv4.
2. Select Create New.
3. Use the following values in the Policy:

Incoming Interface	LAN
Source Address	all
Outgoing Interface	wan1
Destination Address	all
Schedule	always
Service	all
Action	ACCEPT
Enable NAT	enabled -- Use Destination Interface Address
Antivirus	<ON> default
DLP	<ON> Copyrighted
SSL/SSH Inspection	<ON> default
Enable this policy	<ON>

This policy should be place as close to the beginning of the list of policies so the it is among the first tested against.

6. Create a policy to block transmission of copyrighted material.
   This will in effect be the default template for all following policies in that they will have to use the DLP profile that blocks the transmission of the copyrighted material.

1. Go to Policy & Objects > Policy > IPv4
2. Select Create New or Edit an existing policy.
3. Use the following values in the Policy:

The fields should include what ever values you need to accomplish your requirements are but each policy should include the DLP sensor block_copyrighted or if a different DLP configuration is required it should include a filter that blocks copyrighted fingerprinted file.

If you need to create a policy that is identity based make sure that there is an Authentication rule for the group employees that uses the DLP sensor that blocks copyrighted material.