Dynamic Resolution: Fast Flux DNS T1568.001

Tactic: Command & Control

Adversaries may use Fast Flux DNS to hide a command and control channel behind an array of rapidly changing IP addresses linked to a single domain resolution. This technique uses a fully qualified domain name, with multiple IP addresses assigned to it which are swapped with high frequency, using a combination of round robin IP addressing and short Time-To-Live (TTL) for a DNS resource record.

Authoring guide

Patterns shared across the 1 rule above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.

Fields filtered most (7 distinct)

The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.

FieldRulesHowSample values
Action1eq 1Deny
AlertTimeSrcIpDenyRateCount1gt 1LearningThreshold
Fqdn1is_not_null 1
LearningTimeBuckets1gt 15
OperationName1eq 1AzureFirewallApplicationRuleLog, AzureFirewallNetworkRuleLog
TimeGenerated1ge 1, le 1FullWindowEnd, FullWindowStart
src_ip1is_not_null 1

Top indicator values (7 distinct)

Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique. Click a value to expand the rules under this technique that use it.

FieldKindValueRules (here)Corpus reach
Actioneq
Deny
12
AlertTimeSrcIpDenyRateCountgt
LearningThreshold
12
LearningTimeBucketsgt
5
12
OperationNameeq
AzureFirewallApplicationRuleLog
14
OperationNameeq
AzureFirewallNetworkRuleLog
13
TimeGeneratedge
FullWindowStart
1
TimeGeneratedle
FullWindowEnd
1

Rules under this technique

Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.

Platform (all)
Domain (all)

Kusto 1 rule