referring to @to4kawa SPL, I performed minor changes to achieve the result
Try this
| makeresults
| eval json="{\"event_timestamp\":\"2020-03-03 T 12:56:54 +0200\",\"file_timestamp\":\"\",\"username\":\"xxxx\",\"session_id\":\"F23AA957F1A494C12F2B21B5A7533FF3\",\"request_id\":\"74b9cf97-934c-41cb-b81e-1152f51e28b7\",\"register_id\":[],\"system_id\":\"ASDFG\",\"environment\":\"LINUX\",\"service_id\":\"12355\",\"parameters\":[{\"field\":\"xxx\",\"value\":\"xx-123\",\"search\":false,\"securityProhibition\":false},{\"field\":\"yyy\",\"value\":\"yy-564\",\"search\":false,\"securityProhibition\":false},{\"field\":\"zzz\",\"value\":\"1234433222\",\"search\":false,\"securityProhibition\":false},{\"field\":\"vvv\",\"value\":\"www.google.com\",\"search\":false,\"securityProhibition\":false},{\"field\":\"qqq\",\"value\":\"qwert\",\"search\":false,\"securityProhibition\":false}],\"info\":null,\"error\":[{\"code\":\"202\",\"message\":\"General Error\"}],\"schema_version\":\"1.0\"}\";"
| rex "(?<json>\{.+)"
| spath input=json
| fields - json
| rename parameters{}.* as *
| eval fieldValue=mvzip(field,value)
| mvexpand fieldValue
| eval fieldValue=split(fieldValue,",")
| eval field=mvindex(fieldValue,0)
| eval value=mvindex(fieldValue,1)
| fields - fieldValue search securityProhibition
... View more