Correlation rules of the 'operational' type
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Correlation rules of the operational type are used for working with active lists. Settings for a correlation rule of the operational type are described in the following tables.
General tab
This tab lets you specify the general settings of the correlation rule.
Setting
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Description
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Name
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Unique name of the resource. The maximum length of the name is 128 Unicode characters.
Required setting.
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Tenant
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The name of the tenant that owns the resource.
Required setting.
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Type
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Correlation rule type: operational.
Required setting.
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Tags
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Rate limit
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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 .
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Description
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Description of the resource. The maximum length of the description is 4000 Unicode characters.
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MITRE techniques
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Downloaded MITRE ATT&CK techniques for analyzing the security coverage status using the MITRE ATT&CK matrix.
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Selectors tab
This tab is used to define the conditions that the processed events must fulfill to trigger the correlation rule. A selector has a Settings tab and a Local variables tab.
The settings available on the Settings tab are described in the table below.
Setting
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Description
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Filter
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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? To create a filter:
- In the Filter drop-down list, select Create new.
- If you want to keep the filter as a separate resource, select the Save filter check box. In this case, you will be able to use the created filter in various services. This check box is cleared by default.
- If you selected the Save filter check box, enter a name for the created filter resource in the Name field. Maximum length of the name: 128 Unicode characters.
- Under Conditions, specify the conditions that the events must meet:
- Click the Add condition button.
- In the Left operand and Right operand drop-down lists, specify the search parameters. Depending on the data source selected in the Right operand field, fields of additional parameters for identifying the value to be passed to the filter may be displayed. For example, when you select active list, you must specify the name of the active list, the entry key, and the entry key field.
- In the operator drop-down list, select an operator.
Filter operators - =—the left operand equals the right operand.
- <—the left operand is less than the right operand.
- <=—the left operand is less than or equal to the right operand.
- >—the left operand is greater than the right operand.
- >=—the left operand is greater than or equal to the right operand.
- inSubnet—the left operand (IP address) is in the subnet of the right operand (subnet).
- contains—the left operand contains values of the right operand.
- startsWith—the left operand starts with one of the values of the right operand.
- endsWith—the left operand ends with one of the values of the right operand.
- match—the left operand matches the regular expression of the right operand. The RE2 regular expressions are used.
- hasBit—checks whether the left operand (string or number) contains bits whose positions are listed in the right operand (in a constant or in a list).
The value to be checked is converted to binary and processed right to left. Chars are checked whose index is specified as a constant or a list. If the value being checked is a string, then an attempt is made to convert it to integer and process it in the way described above. If the string cannot be converted to a number, the filter returns False . - hasVulnerability—checks whether the left operand contains an asset with the vulnerability and vulnerability severity specified in the right operand.
If you do not specify the ID and severity of the vulnerability, the filter is triggered if the asset in the event being checked has any vulnerability. - inActiveList—this operator has only one operand. Its values are selected in the Key fields field and are compared with the entries in the active list selected from the Active List drop-down list.
- inDictionary—checks whether the specified dictionary contains an entry defined by the key composed with the concatenated values of the selected event fields.
- inCategory—the asset in the left operand is assigned at least one of the asset categories of the right operand.
- inActiveDirectoryGroup—the Active Directory account in the left operand belongs to one of the Active Directory groups in the right operand.
- TIDetect—this operator is used to find events using CyberTrace Threat Intelligence (TI) data. This operator can be used only on events that have completed enrichment with data from CyberTrace Threat Intelligence. In other words, it can only be used in collectors at the destination selection stage and in correlators.
- inContextTable—presence of the entry in the specified context table.
- intersect—presence in the left operand of the list items specified in the right operand.
- If you want the operator to be case-insensitive, select the do not match case check box. The selection of this check box does not apply to the InSubnet, InActiveList, InCategory or InActiveDirectoryGroup operators. This check box is cleared by default.
- If you want to add a negative condition, select If not from the If drop-down list.
You can add multiple conditions or a group of conditions. - If you have added multiple conditions or groups of conditions, choose a selection condition (and, or, not) by clicking the AND button.
- If you want to add existing filters that are selected from the Select filter drop-down list, click the Add filter button. You can view the nested filter settings by clicking the
button.
Filtering based on data from the Extra event field Conditions for filters based on data from the Extra event field:
- Condition—If.
- Left operand—event field.
- In this event field, you can specify one of the following values:
Extra field.- Value from the
Extra field in the following format:Extra.< field name > For example, Extra.app . You must specify the value manually. - Value from the array written to the
Extra field in the following format:Extra.< field name >.< array element > For example, Extra.array.0 . The values in the array are numbered starting from 0. You must specify the value manually. To work with a value in the Extra field at a depth of 3 and lower, you must use backticks ``, for example, `Extra.lev1.lev2.lev3` .
- Operator – =.
- Right operand—constant.
- Value—the value by which you need to filter events.
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.
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On the Local variables tab, you can add variables that will be valid inside the correlation rule. To add a variable, click the + Add button, then specify the variable and its value. You can add multiple variables or delete variables. To delete a variable, select the check box next to it and click the Delete button.
Actions tab
You can use this tab to configure the trigger of the correlation rule. A correlation rule of the operational type can have only one trigger, which is activated each time the bucket registers the selector triggering. Available trigger settings are listed in the table below.
Setting
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Description
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Active lists update
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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.
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Updating context tables
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Operations with context tables. To create an operation with a context table, click the + Add context table action button.
Available parameters of a context table operation:
- Name specifies the context table to which the operation is applied. If you want to edit the settings of a context table, click the pencil
icon next to it.Required setting. - Operation is the operation that is applied to the context table:
- Sum—add a constant, the value of a correlation event field, or the value of a local variable to the value of the context table. This operation is used only for fields of Number and Float types.
- Set—write the values of the selected fields of the correlation event into the context table by creating a new or updating an existing context table entry. When the context table entry is updated, the data is merged and only the specified fields are overwritten.
- Merge—append the value of a correlation event field, local variable, or constant to the current value of a field of the context table.
- Get—get the fields of the context table and write the values of the specified fields into the correlation event. Table fields of the boolean type and lists of boolean values are excluded from mapping because the event does not contain boolean fields.
- Delete—delete the context table entry.
Required setting. - Mapping: Rules for mapping context table fields to event fields or variables. You can use mapping rules if in the Operation drop-down list, you selected something other than Delete. To create a mapping rule, click the + Add button.
Available mapping rule settings: - Context table field is the context table field that is mapped to an event field. You cannot specify a context table field that is already used in a mapping. You can specify tabulation characters, special characters, or just numbers. The maximum length of a context table field name is 128 characters. A context table field name cannot begin with an underscore.
- KUMA field is the event field or local variable to which the context table field is mapped.
- Constant is a constant that is assigned to the context table field. You need to specify a constant if in the Operation drop-down list, you selected Set, Merge, or Sum. The maximum length of a constant is 1024 characters.
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 context tables, reorder operations with context tables, or delete operations with context tables. To reorder operations with context tables, use the reorder icons. To delete an operation with a context tables, click the delete icon next to it.
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Correlators tab
This tab is displayed only when you edit the settings of the created correlation rule; on this tab, you can link correlators to the correlation rule.
To add correlators, click the + Add button, specify one or more correlators in the displayed window, and click OK. The correlation rule is linked to the specified correlators and added to the end of the execution queue in the correlator settings. If you want to change the position of a correlation rule in the execution queue, go to the Resources → Correlator section, click the correlator, and in the displayed window, go to the Correlation section, select the check box next to the correlation rule, and change the position of the correlation rule by clicking the Move up and Move down buttons.
You can add multiple correlators or delete correlators. To delete a correlator, select the check box next to it and click Delete.
Article ID: 221203, Last review: Apr 23, 2025