ATT&CK coverage › Technique

Phishing `T1566`

Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns.

Events covered

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

Provider	Event ID	Title
Sysmon	1	Process creation
Sysmon	11	FileCreate
Sysmon	13	RegistryEvent (Value Set)
Sysmon	22	DNSEvent (DNS query)
Security-Auditing	4688	A new process has been created.

Authoring guide

Patterns shared across the 8 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized 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 (10 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.

Field	Rules	How	Sample values
`Image`	5	`ends_with` 5, `match` 1	`\MSHTA.EXE`, `\rundll32.exe`, `\wmic.exe`, `\PowerISO.exe`, `\ImgBurn.exe`
`ParentImage`	3	`ends_with` 3	`\hh.exe`, `\peazip.exe`, `\7zFM.exe`, `\Winrar.exe`, `\onenote.exe`
`TargetFilename`	2	`ends_with` 1, `match` 1, `eq` 1	`\Microsoft\OneDrive\`, `\api-ms-win-core-`, `\Local\slack\app-`, `"\\AppData\\Local\\Microsoft\\FORMS\\IPM"`
`OriginalFileName`	2	`eq` 2	`HH.exe`, `WorkFolders.exe`, `PowerShell.EXE`, `wmic.exe`
`CommandLine`	2	`match` 2, `ends_with` 1	`\Content.Outlook\`, `\AppData\Local\Temp\`, `\Windows\Temp\`, `.pif`, `.scr`
`Domain`	1	`is_not_null` 1
`registry_path`	1	`eq` 1	`"\\InProcServer32\\"`
`Details`	1	`eq` 1	`\\FORMS\\`
`file_name`	1	`eq` 1	`"*.dll"`
`process_name`	1	`eq` 1	`outlook.exe`

Top indicator values (126 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.

Field	Kind	Value	Rules (here)	Corpus reach
`Image`	`ends_with`	`\cscript.exe`	3	64
`Image`	`ends_with`	`\wscript.exe`	3	64
`Image`	`ends_with`	`\cmd.exe`	3	92
`Image`	`ends_with`	`\pwsh.exe`	3	140
`Image`	`ends_with`	`\powershell.exe`	3	143
`Image`	`ends_with`	`\installutil.exe`	2	5
`Image`	`ends_with`	`\msiexec.exe`	2	21
`Image`	`ends_with`	`\regsvr32.exe`	2	57
`Image`	`ends_with`	`\rundll32.exe`	2	76
`Image`	`ends_with`	`\wmic.exe`	2	37
`Image`	`ends_with`	`\schtasks.exe`	2	45
`Image`	`ends_with`	`\mshta.exe`	2	57
`Image`	`ends_with`	`\certutil.exe`	2	34
`Image`	`ends_with`	`\curl.exe`	2	19
`Image`	`ends_with`	`\hh.exe`	2	14
`OriginalFileName`	`eq`	`HH.exe`	2	5
`Image`	`ends_with`	`\CertReq.exe`	1	5
`ParentImage`	`ends_with`	`\hh.exe`	1
`Image`	`ends_with`	`\CertUtil.exe`	1
`Image`	`ends_with`	`\MSbuild.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.

Sigma 5 rules

HTML Help HH.EXE Suspicious Child Process severity high, 2 events, 16 indicators, 0 exclusions
Phishing Pattern ISO in Archive severity high, 2 events, 6 indicators, 0 exclusions
Potential Initial Access via DLL Search Order Hijacking severity medium, 1 event, 23 indicators, 0 exclusions
Suspicious HH.EXE Execution severity high, 1 event, 8 indicators, 0 exclusions
Suspicious Microsoft OneNote Child Process severity high, 1 event, 89 indicators, 0 exclusions

Splunk 2 rules

Windows InProcServer32 New Outlook Form 1 event, 2 indicators, 0 exclusions
Windows Phishing Outlook Drop Dll In FORM Dir 2 events, 3 indicators, 0 exclusions

Kusto Query Language 1 rule

RecordedFuture Threat Hunting Domain All Actors 1 event, 0 indicators, 0 exclusions

Phishing T1566