Email Collection T1114

Adversaries may target user email to collect sensitive information. Emails may contain sensitive data, including trade secrets or personal information, that can prove valuable to adversaries. Emails may also contain details of ongoing incident response operations, which may allow adversaries to adjust their techniques in order to maintain persistence or evade defenses. Adversaries can collect or forward email from mail servers or clients.

Events covered

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

Authoring guide

Patterns shared across the 13 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 (20 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
CommandLine4contains 2, match 1, regex_match 1, wildcard 1$exserver=Get-ExchangeServer..., (?i)-FilePath.{1,}\.pst, *-Mailbox*-ContentFilter*, *MailboxExportRequest*, -encodedcommand
ScriptBlockText4contains 3, in 1*invoke-addgmailrule*, *invoke-domainharvestowa*, *invoke-globalmailsearch*, -comobject outlook.application, deletemessage
EventID3eq 34104, 4103, 4688
event.type3eq 3start
process_name3eq 3powershell.exe, powershell_ise.exe, pwsh.exe, cmd.exe, cscript.exe
process.args2ends_with 1, wildcard 1.ost, .pst, Set-CASMailbox*ActiveSyncAllowedDeviceIDs*
EfectiveCommand1regex_match 1regexEmpire
EventData1contains 1-encodedcommand, powershell.exe, powershell_ise.exe
EventType1eq 1start
Image1ends_with 1\powershell.exe, \pwsh.exe
OriginalFileName1eq 1powershell.exe, pwsh.dll
ParentImage1eq 1c:\windows\system32\msiexec.exe
TargetFilename1ne 1c:\users\*\appdata\local\microsoft\outlook*, c:\users\*\my documents\outlook files\*
Workstation1eq 1RULER
WorkstationName1eq 1RULER

Top indicator values (77 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
event.typeeq
start
3241
process_nameeq
powershell.exe
399
process_nameeq
pwsh.exe
360
process_nameeq
powershell_ise.exe
250
EventIDeq
4104
2268
EventIDeq
4103
1105
EventIDeq
4688
1312
ScriptBlockTextcontains
new-inboxrule
22
ScriptBlockTextcontains
set-inboxrule
22
ScriptBlockTextcontains
-comobject outlook.application
1
ScriptBlockTextcontains
deletemessage
1
CommandLinecontains
-encodedcommand
13
CommandLinecontains
add-pssnapin
13
CommandLinecontains
microsoft.exchange.management.powershell.snapin
1
CommandLinecontains
microsoft.exchange.powershell.snapin
1
CommandLinematch
$exserver=Get-ExchangeServer ([Environment]::MachineName) -ErrorVariable...
1
CommandLineregex_match
(?i)-FilePath.{1,}\.pst
1
CommandLinewildcard
*-Mailbox*-ContentFilter*
1
CommandLinewildcard
*MailboxExportRequest*
1
EfectiveCommandregex_match
regexEmpire
1
EventDatacontains
-encodedcommand
1
EventDatacontains
powershell.exe
1
EventDatacontains
powershell_ise.exe
1
EventDatacontains
pwsh.exe
1
EventTypeeq
start
116
Imageends_with
\powershell.exe
1186
Imageends_with
\pwsh.exe
1172
OriginalFileNameeq
powershell.exe
1121
OriginalFileNameeq
pwsh.dll
1112
ParentImageeq
c:\windows\system32\msiexec.exe
15

Exclusions (9 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
CommandLinematch
$exserver=Get-ExchangeServer ([Environment]::MachineName) -ErrorVariable...
1
EventDatacontains
gc_service.exe
1
EventDatacontains
gc_worker.exe
1
ParentImagecontains
gc_service.exe
1
ParentImagecontains
gc_worker.exe
1
ParentImageeq
c:\windows\system32\msiexec.exe
1
process.argscontains
davclnt.dll,davsetcookie
1
process_nameeq
outlook.exe
1
process_nameeq
rundll32.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

Elastic 4 rules

Splunk 3 rules

Kusto 1 rule