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Skyhigh Security

Create Custom Advanced Patterns using Add Regex

You can use this option to add regex manually and then validate it using the validation algorithm. Additionally, you can use the BIN or Luhn validator to manage your credit or debit cards' Bank Identification Numbers (BIN). To minimize the number of false positives, you can add Ignored Expressions to exclude specific keywords or regular expressions from being processed as matches in DLP classifications.

To manually add regex to your Custom Advanced Patterns:

  1. Go to Policy > DLP Policies > Classifications.
  2. Click Actions > Create Classification
  3. Classification Name. Enter a name for this classification. For example, New Advanced Pattern. Enter an optional description to describe its use or purpose.
  4. Category. Select a Category from the list.  For example, Sensitive.
  5. Conditions. Click Select Criteria and choose Advanced Pattern. The Select Advanced Patterns cloud card displays.
    • Count each match string only one time. When you select this checkbox, a string that matches the advanced pattern in the advanced pattern rule will not be counted again. To learn more about the use case, see Count each match string only one time feature.

NOTE: If you enable the Count each match string only one time checkbox, the unique match criteria apply to each advanced pattern in the classification. For example, if your classification has two advanced patterns with the same regular expression, then the classification will trigger two separate matches for the same regular expression.

 

  1. Click New.

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  2. Enter a name and optional description for your Custom Advanced Pattern.
  3. To manually enter a regular expression, click Add RegEx.

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  4. Enter a regular expression, your newly added regular expression can be seen on the Regular Expressions tab.
  5. To ensure your regular expressions are accurate, click No Validation to open the Validation Algorithm cloud card. 

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  6. Select the appropriate Validation Algorithm from the list and click Done. To add Luhn 10 Validation Algorithm and BINs for your custom regular expressions, click Add BIN Validator. For more details, see Add BIN Validator.

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  7. Add a Score to weigh the new regex Advanced Pattern. Scores can be between negative or positive, -99 to 999. The higher the number, the greater the weight given to the keyword, which will exceed the threshold and trigger an incident. 
  8. To reduce false positives, add expressions in the Exceptions tab to exclude specific keywords or regular expressions from being processed as matches in DLP classifications. 
  9. Go to the Exceptions tab and click Add Exception.

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  10. Enter the keywords or Google RE2 expressions (RegEx) and select the Type of the exception from the menu. To add more expressions, click Add Exception.

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  11. To save your new Advanced Pattern with regular expressions and exceptions, click Save.
  12. The new Advanced Pattern is now added to the Classification and Advanced Pattern list.

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  13. Optionally, you can edit the threshold by clicking [1]. Enter a number to indicate the weight of the Advanced Pattern in threshold matching.

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  14. Add more classification conditions as needed and click Save.

Your custom classification with custom advanced patterns, validations, and exceptions are saved to the selected category in the Classifications list. Add the classification to your DLP policies as needed.​​​​​​

NOTE: You can view events for new, updated, and deleted advanced patterns in the Audit Log. For details, see View DLP Classification Events in the Audit Log

 

Custom Advanced Pattern Use Cases

Count each match string only one time feature 

Suppose you have a bank document with multiple instances of the pattern for France IBAN and you have set the score for this regular expression as 10 in the custom advanced pattern. This means that a match will only be triggered if the pattern France IBAN appears 10 or more times in the document. However, if you want to avoid triggering matches for duplicate counts, you can activate the Count each match string only one time checkbox. During the policy evaluation, the match will count only once, even though the score for the regular expression is set to 10. To find this option on UI, see Count each match string only one time.

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Set Scores for Regular Expressions on the Custom Advanced Pattern List

Let's say you have a confidential bank document containing sensitive information or patterns that should only be accessed by authorized personnel. To ensure the security of the document, you can set the scores for regular expressions that alert the DLP scanning engine with more precise information whenever someone tries to access sensitive patterns beyond a specific limit. If a match is found, an incident is triggered to maintain the document's security.

To set scores for each regular expression in a custom advanced pattern list, follow these steps:

  1. Create a classification using custom advanced patterns. Perform the initial steps of creating your advanced pattern classification as provided in steps 1 to 11 in the Create Custom Advanced Patterns using Add Regex section.
  2. Score. Once you add the necessary regular expressions, you can set different scores for each regular expression in the list by editing the default score [1]. For example, configure the scores for three regular expressions - France IBAN, German IBAN, and UK IBAN. Set the score for France IBAN to 10, German IBAN to 6and UK IBAN to 5. This means that when the patterns for France IBAN are accessed 10 or more times in the content, German IBAN is accessed 6 or more times, and UK IBAN is accessed 5 or more times then it triggers a match.

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Re-use Regular Expressions in Custom Advanced Pattern List

Suppose you have multiple confidential documents containing common patterns, such as credit card numbers, that should only be accessed by authorized personnel. To ensure the security of these documents, you can create a custom advanced pattern list using regular expressions. This list can then be reused across classifications, eliminating the need to create or update custom advanced pattern lists repeatedly. 

To re-use regular expressions in a custom advanced pattern list:

  1. Create a classification using custom advanced patterns. Follow the steps of creating your advanced pattern classification as outlined in steps 1 to 5 in the Create Custom Advanced Patterns using Add Regex section. 
  2. On the Select Advanced Patterns cloud card, click All and select Custom.

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  3. Select one or more existing Custom Advanced Patterns.
  4. Click i to view the Usage of the selected Advanced Patterns in other classifications.

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Exclude Matches on Keywords in Custom Advanced Pattern List

Suppose you have a financial document that contains a broad range of sensitive keywords, but you want to exclude specific keywords from being processed as matches by the DLP engine. To exclude matches on keywords, you can create a custom advanced pattern list using regular expressions and exceptions. These exceptions prevent specific keywords from triggering matches, thereby reducing false positives and ensuring accuracy in your data protection measures. 

To exclude matches on keywords in a custom advanced pattern list:

  1. Create a classification using custom advanced patterns. Follow the steps of creating your advanced pattern classification as outlined in steps 1 to 14 in the Create Custom Advanced Patterns using Add Regex section.
  2. Exception and Type. Once you add the necessary regular expressions, you can add exceptions to exclude specific keywords or regular expressions from being processed as matches by the DLP engine. For example, add exceptions such as two keywords - Account No and Balance, and add a regular expression for Spain IBAN. This means that a match will not be triggered if the keywords Account No and Balance, and patterns for Spain IBAN are accessed within the document.

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Exclude Matches on Regular Expressions in Custom Advanced Pattern List

Suppose you have a financial document that contains a broad range of sensitive patterns, but you want to exclude specific patterns from being processed as matches by the DLP engine. To exclude matches on regular expressions, you can create a custom advanced pattern list using regular expressions and exceptions. These exceptions prevent specific patterns from triggering matches, thereby reducing false positives and ensuring accuracy in your data protection measures. 

To exclude matches on regular expressions in a custom advanced pattern list:

  1. Create a classification using custom advanced patterns. Follow the steps of creating your advanced pattern classification as outlined in steps 1 to 14 in the Create Custom Advanced Patterns using Add Regex section.
  2. Exception and Type. Once you add the necessary regular expressions, you can add exceptions to exclude specific keywords or regular expressions from being processed as matches by the DLP engine. For example, add exceptions such as two regular expressions - Netherlands IBAN and Italian IBAN No, and add a keyword Account No. This means that a match will not be triggered if the patterns for Netherlands IBAN and Italian IBAN, and keyword Account No are accessed within the document.

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Match Regular Expressions in Specific Email Sections

Suppose you have a medical email that contains a broad range of sensitive text patterns, but you want the DLP engine to match text patterns in specific sections of the email. To match regular expressions in specific sections of the email, you must first create a classification using a custom advanced pattern list of regular expressions. You can then configure a DLP policy with the newly created classification to specify the sections (Everywhere, Email Header) of the email. This enables the DLP engine to trigger matches on regular expressions in specific sections of the email, thereby reducing false positives and ensuring accuracy in your data protection measures. 

For example, create a classification using a custom advanced pattern list of regular expressions named Bank Account Numbers, and configure a sanctioned DLP policy with the new classification to specify the Email Header section of the email. This ensures that a match is only triggered if the regular expressions in the Bank Account Numbers advanced pattern list are accessed in the header section of the email.

To match regular expressions in specific email sections:

  1. Create a classification by selecting any of or all of Custom Advanced Patterns.

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  2. Create a Sanctioned or Shadow DLP policy using the newly created classification. For example, create a sanctioned DLP policy. 
  3. Use the Skyhigh CASB DLP policy wizard to perform the initial steps of creating your Sanctioned DLP policy as provided in steps 1 to 4 in Create a Sanctioned DLP Policy

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  4. On the Rules & Exceptions page, configure the following:
    • Rules. For IF, select Classifications. The Select Classification cloud card appears.

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      • Classification. Select the newly created classification from the list of supported classifications and click Done.

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        • Location. Select Email Header. By default, All is selected.

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  5. Complete the remaining steps to configure your DLP policy as mentioned from step 5 (c) in Create a Sanctioned DLP Policy.
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