Internal Spearphishing T1534

Tactic: Lateral Movement

After they already have access to accounts or systems within the environment, adversaries may use internal spearphishing to gain access to additional information or compromise other users within the same organization. Internal spearphishing is multi-staged campaign where a legitimate account is initially compromised either by controlling the user's device or by compromising the account credentials of the user. Adversaries may then attempt to take advantage of the trusted internal account to increase the likelihood of tricking more victims into falling for phish attempts, often incorporating Impersonation.

Authoring guide

Patterns shared across the 4 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 (11 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
EventOriginalType1eq 1PowerAppPermissionEdited
EventType1eq 1Publish
InvitedId1is_not_null 1
OperationName1eq 1Invite external user
Provider_Name1eq 1sns.amazonaws.com
Result1eq 1success
SourceSystem1eq 1Azure AD
Type1eq 1email_iep
data_stream.dataset1eq 1aws.cloudtrail
event.outcome1eq 1success
mimecastEventId_s1eq 1mail_ttp_iep

Top indicator values (10 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
EventOriginalTypeeq
PowerAppPermissionEdited
1
EventTypeeq
Publish
1
OperationNameeq
Invite external user
14
Provider_Nameeq
sns.amazonaws.com
13
Resulteq
success
125
SourceSystemeq
Azure AD
1
Typeeq
email_iep
1
data_stream.dataseteq
aws.cloudtrail
1141
event.outcomeeq
success
1251
mimecastEventId_seq
mail_ttp_iep
1

Exclusions (1 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
InvitedOrgDomaincontains
allowed_domains
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)

Elastic 1 rule

Kusto 3 rules