Detection rules › Kusto Query Language
Detect excessive NXDOMAIN DNS queries - Static threshold based (ASIM DNS Solution)
'This rule generates an alert when the configured threshold for DNS queries to non-existent domains is breached. This helps in identifying possible C2 communications. It utilizes ASIM normalization and is applied to any source that supports the ASIM DNS schema.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1008 Fallback Channels, T1568 Dynamic Resolution |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 22 | DNSEvent (DNS query) |
Stages and Predicates
Stage 1: source
_Im_Dns
Stage 2: summarize
Stage 3: where
NXDOMAINCount gt "threshold"
Stage 4: join
Stage 5: extend
Stage 6: project-away
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
NXDOMAINCount | gt |
|