Input Capture: Credential API Hooking T1056.004

Tactics: Collection, Credential Access

Adversaries may hook into Windows application programming interface (API) functions and Linux system functions to collect user credentials. Malicious hooking mechanisms may capture API or function calls that include parameters that reveal user authentication credentials. Unlike Keylogging, this technique focuses specifically on API functions that include parameters that reveal user credentials.

Events covered

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

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 (6 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
EventID3eq 34688, 1
Type3eq 3
CommandLine1contains 1-encodedcommand
EfectiveCommand1regex_match 1regexEmpire
EventData1contains 1-encodedcommand, powershell.exe, powershell_ise.exe
event_type1in 1childproc, netconn, proc

Top indicator values (11 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
EventIDeq
4688
2313
EventIDeq
1
1237
CommandLinecontains
-encodedcommand
13
EfectiveCommandregex_match
regexEmpire
1
EventDatacontains
-encodedcommand
1
EventDatacontains
powershell.exe
1
EventDatacontains
powershell_ise.exe
1
EventDatacontains
pwsh.exe
1
event_typein
childproc
127
event_typein
netconn
127
event_typein
proc
127

Exclusions (4 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
EventDatacontains
gc_service.exe
1
EventDatacontains
gc_worker.exe
1
ParentImagecontains
gc_service.exe
1
ParentImagecontains
gc_worker.exe
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)

Splunk 3 rules

Kusto 1 rule