Impersonation T1656
Tactic: Stealth
Adversaries may impersonate a trusted person or organization in order to persuade and trick a target into performing some action on their behalf. For example, adversaries may communicate with victims (via Phishing for Information, Phishing, or Internal Spearphishing) while impersonating a known sender such as an executive, colleague, or third-party vendor. Established trust can then be leveraged to accomplish an adversary’s ultimate goals, possibly against multiple victims. In many cases of business email compromise or email fraud campaigns, adversaries use impersonation to defraud victims -- deceiving them into sending money or divulging information that ultimately enables Financial Theft.
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 (8 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.
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.
Exclusions (19 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.
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.