Active Scanning: Scanning IP Blocks T1595.001

Tactic: Reconnaissance

Adversaries may scan victim IP blocks to gather information that can be used during targeting. Public IP addresses may be allocated to organizations by block, or a range of sequential addresses.

Events covered

3 catalog events are tagged with this technique by at least one rule.

Authoring guide

Patterns shared across the 11 rules 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 (19 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
DestinationPort5is_not_null 3, in 1, lt 1139, 21, 22, 32000
src_ip5is_not_null 3, in 2, cidr_match 110.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
EventType3in 3flow_started, network_flow
Fqdn2is_not_null 2
OperationName2eq 2AzureFirewallApplicationRuleLog, AzureFirewallNetworkRuleLog
AlertTimedCountHostsInBinTime1gt 1200
AlertTimedCountPortsInBinTime1gt 1100
All_Traffic.app1contains 1\\
CommandLine1contains 1 f , r , s
Esql.count_distinct_destination_ports1ge 150
Esql.count_distinct_sensitive_ports1ge 15
Esql.event_count1gt 150
Esql.url_original_count_distinct1gt 110
Esql.user_agent_original_to_lower1contains 1, eq 1, starts_with 1acunetix, arachni, burp
dest_count1gt 110

Top indicator values (70 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
EventTypein
flow_started
33
EventTypein
network_flow
33
OperationNameeq
AzureFirewallApplicationRuleLog
24
OperationNameeq
AzureFirewallNetworkRuleLog
23
src_ipin
10.0.0.0/8
29
src_ipin
172.16.0.0/12
29
src_ipin
192.168.0.0/16
29
AlertTimedCountHostsInBinTimegt
200
1
AlertTimedCountPortsInBinTimegt
100
1
All_Traffic.appcontains
\\
1
CommandLinecontains
f
1
CommandLinecontains
r
1
CommandLinecontains
s
1
CommandLinecontains
-i
12
CommandLinecontains
-i:
1
CommandLinecontains
-input
1
CommandLinecontains
-input:
1
CommandLinecontains
-m
14
CommandLinecontains
-m:
1
CommandLinecontains
-mode
1
CommandLinecontains
-mode:
1
CommandLinecontains
:f
1
CommandLinecontains
:r
1
CommandLinecontains
:s
1
CommandLinecontains
scan
1
CommandLinecontains
scanall
1
DestinationPortin
139
14
DestinationPortin
21
12
DestinationPortin
22
14
DestinationPortin
23
12

Exclusions (11 distinct)

Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths. Click a value to expand the rules under this technique that exclude it.

FieldKindValueRules excluding
DestinationPortin
443
2
DestinationPortin
80
2
DestinationPortin
25
1
DestinationPortin
3268
1
DestinationPortin
389
1
DestinationPortin
53
1
DestinationPortin
5353
1
DestinationPortin
8080
1
DestinationPortin
8443
1
DestinationPortin
88
1
src_ipeq
[]
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)

Sigma 1 rule

Elastic 5 rules

Splunk 1 rule

Kusto 2 rules

Panther 2 rules