⚠️ WARNING THIS IS A EXPERIMENTAL DETECTION
We have not been able to test, simulate or build datasets for it, use at your own risk!
This search identifies DNS query failures by counting the number of DNS responses that do not indicate success, and trigger on more than 50 occurrences.
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Network_Resolution
- Last Updated: 2020-07-21
- Author: Bhavin Patel, Splunk
- ID: 104658f4-afdc-499e-9719-17243f9826f1
|T1071.004||DNS||Command And Control|
| tstats `security_content_summariesonly` count values("DNS.query") as queries from datamodel=Network_Resolution where nodename=DNS "DNS.reply_code"!="No Error" "DNS.reply_code"!="NoError" DNS.reply_code!="unknown" NOT "DNS.query"="*.arpa" "DNS.query"="*.*" by "DNS.src","DNS.query" | `drop_dm_object_name("DNS")` | lookup cim_corporate_web_domain_lookup domain as query OUTPUT domain | where isnull(domain) | lookup update=true alexa_lookup_by_str domain as query OUTPUT rank | where isnull(rank) | stats sum(count) as count mode(queries) as queries by src | `get_asset(src)` | where count>50 | `excessive_dns_failures_filter`
Associated Analytic Story
How To Implement
To successfully implement this search you must ensure that DNS data is populating the Network_Resolution data model.
Kill Chain Phase
- Command and Control
Known False Positives
It is possible legitimate traffic can trigger this rule. Please investigate as appropriate. The threshold for generating an event can also be customized to better suit your environment.
source | version: 2