Kaspersky Unified Monitoring and Analysis Platform

Tenant

The name of the tenant that owns the resource.

Required setting.

Tags

Window, sec

Bucket lifetime in seconds. The time starts counting when the bucket is created, when the bucket receives the first event.

When the bucket lifetime expires, the trigger specified on the Actions → On timeout tab is triggered, and the container is deleted. Triggers specified on the Actions → On every threshold and On subsequent thresholds tabs can trigger more than once during the lifetime of the bucket.

Required setting.

Rate limit

Maximum number of times a correlation rule can be triggered per second. The default value is 0.

If correlation rules employing complex logic for pattern detection are not triggered, this may be due to the way rule triggers are counted in KUMA. In this case, we recommend increasing the Rate limit, for example, to 1000000.

Severity

Base coefficient used to determine the importance of a correlation rule:

• Critical
• High
• Medium
• Low (default)

Description

Description of the resource. The maximum length of the description is 4000 Unicode characters.

Use unique field mapping

Selector threshold (event count)

The number of events that must be received for the selector to trigger. The default value is 1.

Required setting.

Filter

The filter that defines criteria for identifying events that trigger the selector when received. You can select an existing filter or create a new filter. To create a new filter, select Create new.

If you want to edit the settings of an existing filter, click the pencil icon next to it.

How to create a filter?

Filtering based on data from the Extra event field

The order of conditions specified in the selector filter of the correlation rule is significant and affects system performance. We recommend putting the most unique condition in the first place in the selector filter.

Consider two examples of selector filters that select successful authentication events in Microsoft Windows.

Selector filter 1:

Condition 1: DeviceProduct = Microsoft Windows.

Condition 2: DeviceEventClassID = 4624.

Selector filter 2:

Condition 1: DeviceEventClassID = 4624.

Condition 2: DeviceProduct = Microsoft Windows.

The order of conditions specified in selector filter 2 is preferable because it places less load on the system.

Loop to correlator

This check box enables the processing of the created correlation event by the rule chain of the current correlator. This makes hierarchical correlation possible. By default, this check box is cleared.

If the Output and Loop to correlator check boxes are selected, the correlation rule is sent to post-processing first, and then to the selectors of the current correlation rule.

Enrichment

Enrichment rules for modifying the values of correlation event fields. Enrichment rules are stored in the correlation rule where they were created. To create an enrichment rule, click the + Add enrichment button.

Available enrichment rule settings:

• Original type is the type of the enrichment. When you select some enrichment types, additional settings may become available that you must specify.

  Available types of enrichment:

  • constant

    This type of enrichment is used when a constant needs to be added to an event field. Available enrichment type settings are listed in the table below.

    Available enrichment type settings

    Setting	Description
    Constant	The value to be added to the event field. Maximum length of the value: 255 Unicode characters. If you leave this field blank, the existing event field value is removed.
    Target field	The KUMA event field that you want to populate with the data.

    If you are using the event enrichment functions for extended schema fields of "String", "Number", or "Float" type with a constant, the constant is added to the field.

    If you are using the event enrichment functions for extended schema fields of "Array of strings", "Array of numbers", or "Array of floats" type with a constant, the constant is added to the elements of the array.

  • dictionary

    This type of enrichment is used if you need to add a value from the dictionary of the Dictionary type. Available enrichment type settings are listed in the table below.

    Available enrichment type settings

    Setting	Description
    Dictionary name	The dictionary from which the values are to be taken.
    Key fields	Event fields whose values are to be used for selecting a dictionary entry. To add an event field, click Add field. You can add multiple event fields.

    If you are using event enrichment with the dictionary type selected as the Source kind setting, and an array field is specified in the Key enrichment fields setting, when an array is passed as the dictionary key, the array is serialized into a string in accordance with the rules of serializing a single value in the TSV format.

    Example: The Key fields setting of the enrichment uses the SA.StringArrayOne extended schema field. The SA.StringArrayOne extended schema field contains the values "a", "b", "c". The following values are passed to the dictionary as the key: ['a','b','c'].

    If the Key enrichment fields setting uses an array extended schema field and a regular event schema field, the field values are separated by the "|" character when the dictionary is queried.

    Example: The Key enrichment fields setting uses the SA.StringArrayOne extended schema field and the Code string field. The SA.StringArrayOne extended schema field contains the values "a", "b", "c", and the Code string field contains the myCode sequence of characters. The following values are passed to the dictionary as the key: ['a','b','c']|myCode.

  • table

    This type of enrichment is used if you need to add a value from the dictionary of the Table type. Available enrichment type settings are listed in the table below.

    Available enrichment type settings

    Setting	Description
    Dictionary name	The dictionary from which the values are to be taken.
    Key fields	Event fields whose values are to be used for selecting a dictionary entry. To add an event field, click Add field. You can add multiple event fields.
    Mapping	Event fields for data transfer: Dictionary field specifies dictionary fields from which data is to be transmitted. The available fields depend on the selected dictionary resource. KUMA field specifies event fields to which data is to be transmitted. For some of the selected fields (*custom* and *flex*), in the Label column, you can specify a name for the data written there.

    The first field in the table (Dictionary field) is taken as the key with which the fields selected from the event as key fields are matched (KUMA field). As the key in the Dictionary field, you must select an indicator of compromise by which the enrichment is to be performed, for example, IP address, URL, or hash. In the rule, you must select the event field that corresponds to the selected indicator of compromise in the dictionary field.

    If you want to select multiple key fields, you can specify them using | as a separator (when specifying in the web interface or importing as a CSV file), for example, <IP address>|<user name>.

    You can add new table rows or delete table rows. To add a new table row, click Add new element. To delete a row in the table, click the button.

  • event

    This type of enrichment is used when you need to write a value from another event field to the current event field. Available enrichment type settings are listed in the table below.

    Available enrichment type settings

    Setting	Description
    Target field	The KUMA event field that you want to populate with the data.
    Source field	The event field whose value is written to the target field.

    Clicking opens the Conversion window, in which you can click Add conversion to create rules for modifying the source data before writing them to the KUMA event fields. You can reorder and delete created rules. To change the position of a rule, click next to it. To delete a rule, click next to it.

    Available conversions

    Conversions are modifications that are applied to a value before it is written to the event field. You can select one of the following conversion types from the drop-down list:

    • entropy is used for converting the value of the source field using the information entropy calculation function and placing the conversion result in the target field of the float type. The result of the conversion is a number. Calculating the information entropy allows detecting DNS tunnels or compromised passwords, for example, when a user enters the password instead of the login and the password gets logged in plain text.
    • lower—is used to make all characters of the value lowercase
    • upper—is used to make all characters of the value uppercase
    • regexp – used to convert a value using a specified RE2 regular expression. When you select this type of conversion, a field is displayed in which you must specify the RE2 regular expression.
    • substring is used to extract characters in a specified range of positions. When you select this type of conversion, the Start and End fields are displayed, in which you must specify the range of positions.
    • replace—is used to replace specified character sequence with the other character sequence. When you select this type of conversion, the following fields are displayed:
      • Replace chars specifies the sequence of characters to be replaced.
      • With chars is the character sequence to be used instead of the character sequence being replaced.
    • trim removes the specified characters from the beginning and from the end of the event field value. When you select this type of conversion, the Chars field is displayed in which you must specify the characters. For example, if a trim conversion with the Micromon value is applied to Microsoft-Windows-Sysmon, the new value is soft-Windows-Sys.
    • append appends the specified characters to the end of the event field value. When you select this type of conversion, the Constant field is displayed in which you must specify the characters.
    • prepend prepends the specified characters to the beginning of the event field value. When you select this type of conversion, the Constant field is displayed in which you must specify the characters.
    • replace with regexp is used to replace RE2 regular expression results with the specified character sequence. When you select this type of conversion, the following fields are displayed:
      • Expression is the RE2 regular expression whose results you want to replace.
      • With chars is the character sequence to be used instead of the character sequence being replaced.
    • Converting encoded strings to text:
      • decodeHexString—used to convert a HEX string to text.
      • decodeBase64String—used to convert a Base64 string to text.
      • decodeBase64URLString—used to convert a Base64url string to text.

      When converting a corrupted string or if conversion error occur, corrupted data may be written to the event field.

      During event enrichment, if the length of the encoded string exceeds the size of the field of the normalized event, the string is truncated and is not decoded.

      If the length of the decoded string exceeds the size of the event field into which the decoded value is to be written, the string is truncated to fit the size of the event field.

    Conversions when using the extended event schema

    Whether or not a conversion can be used depends on the type of extended event schema field being used:

    • For an additional field of the "String" type, all types of conversions are available.
    • For fields of the "Number" and "Float" types, the following types of conversions are available: regexp, substring, replace, trim, append, prepend, replaceWithRegexp, decodeHexString, decodeBase64String, and decodeBase64URLString.
    • For fields of "Array of strings", "Array of numbers", and "Array of floats" types, the following types of conversions are available: append and prepend.

     

    When using enrichment of events that have event selected as the Source kind and the extended event schema fields are used as arguments, the following special considerations apply:

    • If the source extended event schema field has the "Array of strings" type, and the target extended event schema field has the "String" type, the values are written to the target extended event schema field in TSV format.

      Example: The SA.StringArray extended event schema field contains values: "string1", "string2", "string3". An event enrichment operation is performed. The result of the event enrichment operation is written to the DeviceCustomString1 extended event schema field. The DeviceCustomString1 extended event schema field contains values: ["string1", "string2", "string3"].

    • If the source and target extended event schema fields have the "Array of strings" type, values of the source extended event schema field are added to the values of the target extended event schema field, and the "," character is used as the delimiter character.

      Example: The SA.StringArrayOne field of the extended event scheme contains the ["string1", "string2", "string3"] values, and the SA.StringArrayTwo field of the extended event scheme contains the ["string4", "string5", "string6"] values. An event enrichment operation is performed. The result of the event enrichment operation is written to the SA.StringArrayTwo field of the extended event scheme. The SA.StringArrayTwo extended event schema field contains values: ["string4", "string5", "string6", "string1", "string2", "string3"].

  • template

    This type of enrichment is used when you need to write the result of processing Go templates into the event field. We recommend matching the value and the size of the field. Available enrichment type settings are listed in the table below.

    Available enrichment type settings

    Setting	Description
    Template	The Go template. Event field names are passed in the {{.EventField}} format, where EventField is the name of the event field from which the value must be passed to the script, for example, {{.DestinationAddress}} attacked from {{.SourceAddress}}.
    Target field	The KUMA event field that you want to populate with the data.

    If you are using enrichment of events that have template selected as the Source kind, and in which the target field has the "String" type, and the source field is an extended event schema field containing an array of strings, you can use one of the following examples for the template:

    • {{.SA.StringArrayOne}}
    • {{- range $index, $element := . SA.StringArrayOne -}}

      {{- if $index}}, {{end}}"{{$element}}"{{- end -}}

    To convert the data in an array field in a template into the TSV format, use the toString function, for example:

    template {{toString .SA.StringArray}}

  Required setting.

• The Debug toggle switch enables resource logging. This toggle switch is turned off by default.
• Tags

You can create multiple enrichment rules, reorder enrichment rules, or delete enrichment rules. To reorder enrichment rules, use the reorder icons. To delete an enrichment rule, click the delete icon next to it.

Active lists update

Operations with active lists. To create an operation with an active list, click the + Add active list action button.

Available parameters of an active list operation:

• Name specifies the active list to which the operation is applied. If you want to edit the settings of an active list, click the pencil icon next to it.

  Required setting.

• Operation is the operation that is applied to the active list:
  • Sum—add a constant, the value of a correlation event field, or the value of a local variable to the value of the active list.
  • Set—write the values of the selected fields of the correlation event into the Active list by creating a new or updating an existing Active list entry. When the Active list entry is updated, the data is merged and only the specified fields are overwritten.
  • Get—get the Active list entry and write the values of the selected fields into the correlation event.
  • Delete—delete the Active list entry.

  Required setting.

• Key fields are event fields that are used to create an active list entry. The specified event fields are also used as the key of the active list entry.

  The active list entry key depends on the available event fields and does not depend on the order in which they are displayed in the KUMA web interface.

  Required setting.

• Mapping: Rules for mapping active list fields to event fields. You can use mapping rules if in the Operation drop-down list, you selected Get or Set. To create a mapping rule, click the + Add button.

  Available mapping rule settings:

  • Active list field is the active list field that is mapped to the event field. The field must not contain special characters or numbers only.
  • KUMA field is the event field to which the active list field is mapped.
  • Constant is a constant that is assigned to the active list field. You need to specify a constant if in the Operation drop-down list, you selected Set.

  You can create multiple mapping rules or delete mapping rules. To delete a mapping rule, select the check box next to it and click Delete.

You can create multiple operations with active lists, reorder operations with active lists, or delete operations with active lists. To reorder operations with active lists, use the reorder icons. To delete an operation with an active list, click the delete icon next to it.