Create an IOC rule ↗

Create new indicator of compromise (IOC) rules and optionally define rule expiration for all IOC rules. You can create an IOC rule either by configuring a single one or by uploading a file that contains multiple IOCs.

Note

To ensure your IOC rules generate issues efficiently and do not overcrowd your Issues table, Cortex XSIAM automatically does the following:

  • Disables any IOC rules that reach 5000 or more hits over 24 hours.
  • Creates a rule exception based on the PROCESS SHA256 field for IOC rules that hit more than 100 endpoints over 72 hours.

If you have the Threat Intel Management add-on included in your license, create an indicator detection rule for File, Domain, and IP Address indicators rather than creating an IOC. For more information, see Generate issues from indicators using indicator rules for prevention and detection.

  1. In Threat Management → Detection Rules → IOC, select + Add IOC.
  2. Configure the IOC criteria.

Configure a single IOC

Configure a single IOC

After investigating a threat, if you identify a malicious artifact, you can generate an issue for the Single IOC right away.

  1. Configure the INDICATOR value on which you want to match.
  2. Configure the IOC TYPE. Options are Full Path, File Name, Domain, Destination IP, and MD5 or SHA256 Hash.
  3. Configure the SEVERITY you want to associate with the issue for the IOC.
  4. (Optional) Enter a comment that describes the IOC.
  5. (Optional) Configure the IOC's REPUTATION and its RELIABILITY.
  6. (Optional) Configure the EXPIRATION settings for this IOC. Default, Specific Expiration Date, No Expiration.
  7. Click Save.

Upload multiple IOCs

Upload multiple IOCs

If you want to match multiple indicators, you can upload the criteria in a CSV file. You can upload IOCs using REST APIs in either CSV or JSON format.

Upload a file, one IOC per line, that contains up to 20,000 IOCs. For example, you can upload multiple file paths and MD5 hashes for an IOC rule. To help you format the upload file in the syntax that Cortex XSIAM accepts, you can download the example file.

  1. Select Upload File.

  2. Drag and drop the CSV file containing the IOC criteria in the drop area of the Upload File dialog or Browse for the file.

    Cortex XSIAM supports files with multiple IOCs in a pre-configured format. For help in determining the format syntax, download the example text file.

  3. Configure the SEVERITY you want to associate with the issue for the IOCs.
  4. Define the DATA FORMAT of the IOCs in the CSV file. Options are Mixed, Full Path, File Name, Domain, Destination IP, and MD5 or SHA256 Hash.
  5. (Optional) Configure the IOC's REPUTATION and its RELIABILITY.
  6. (Optional) Enter an EXPIRATION for the IOC. Default, Specific Expiration Date, No Expiration.

  7. Click Upload.

  8. (Optional) Define any expiration criteria for your IOC rules.

    You can also configure additional expiration criteria per IOC type to apply to all IOC rules of that type. In most cases, IOC types like Destination IP or Host Name are considered malicious only for a short period of time since they are soon cleaned and then used by legitimate services, from which time they only cause false positives. For these types of IOCs, you can set a defined expiration period. The expiration criteria you define for an IOC type will apply to all existing rules and additional rules that you create in the future. By default, Cortex XSIAM does not apply an expiration date set on IOCs.

    1. Select Default Rule Expiration.
    2. Set the expiration for any relevant IOC type. Options are Never, 7 Days, 30 days, 90 days, or 180 days.
    3. Click Save.