Modify Authentication Process: Network Device Authentication T1556.004

Tactics: Defense Impairment, Persistence, Credential Access

Adversaries may use Patch System Image to hard code a password in the operating system, thus bypassing of native authentication mechanisms for local accounts on network devices.

Authoring guide

Patterns shared across the 2 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 (3 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
command1in 1aaa authentication*, aaa authorization*, aaa local authentication*
message_id1in 1111008, 111010
sourcetype1eq 1cisco:asa

Top indicator values (8 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
commandin
aaa authentication*
1
commandin
aaa authorization*
1
commandin
aaa local authentication*
1
commandin
aaa-server*
1
commandin
no aaa*
1
message_idin
111008
17
message_idin
111010
17
sourcetypeeq
cisco:asa
113

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

Splunk 1 rule