Indicator Removal: Clear Mailbox Data T1070.008

Tactic: Stealth

Adversaries may modify mail and mail application data to remove evidence of their activity. Email applications allow users and other programs to export and delete mailbox data via command line tools or use of APIs. Mail application data can be emails, email metadata, or logs generated by the application or operating system, such as export requests.

Events covered

1 catalog event is tagged with this technique by at least one rule.

Authoring guide

Patterns shared across the 9 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
sourcetype7eq 7, in 4o365:management:activity, ms:o365:reporting:messagetrace, o365:reporting:messagetrace, cisco:asa
Operation6eq 4, in 2, starts_with 2HardDelete, send, Send, SendAs, SendOnBehalf
Workload6eq 6Exchange
m365::Folder.Path4in 4\\Recoverable Items\\Deletions, \\Sent Items
Status2eq 2Delivered
subject2in 2*Account Recovery*, *MFA *, *OTP *
EventType1in 1HardDelete, MoveToDeletedItems, SoftDelete
Provider_Name1eq 1Exchange
ScriptBlockText1contains 1\comms\unistore\data
count1gt 150
data_stream.dataset1eq 1o365.audit
event.outcome1eq 1success
externalRecipient1eq 11
file_size1gt 110
firstTime1lt 1

Top indicator values (94 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
Workloadeq
Exchange
620
sourcetypeeq
o365:management:activity
680
Operationeq
HardDelete
44
m365::Folder.Pathin
\\Recoverable Items\\Deletions
44
m365::Folder.Pathin
\\Sent Items
44
sourcetypein
ms:o365:reporting:messagetrace
44
sourcetypein
o365:reporting:messagetrace
44
Operationstarts_with
send
22
Statuseq
Delivered
22
subjectin
*Account Recovery*
22
subjectin
*MFA *
22
subjectin
*OTP *
22
subjectin
*banking*
22
subjectin
*direct deposit*
22
subjectin
*passcode *
22
subjectin
*password *
22
subjectin
*pay-to*
22
EventTypein
HardDelete
1
EventTypein
MoveToDeletedItems
1
EventTypein
SoftDelete
1
Operationin
HardDelete
1
Operationin
Send
1
Operationin
SendAs
1
Operationin
SendOnBehalf
1
Operationin
SoftDelete
1
Provider_Nameeq
Exchange
119
ScriptBlockTextcontains
\comms\unistore\data
1
countgt
50
15
data_stream.dataseteq
o365.audit
145
event.outcomeeq
success
1251

Exclusions (5 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
o365.audit.AffectedItems.Subjectcontains
log in
1
o365.audit.AffectedItems.Subjectcontains
log-in
1
o365.audit.AffectedItems.Subjectcontains
logon
1
o365.audit.AffectedItems.Subjectcontains
sign in
1
o365.audit.AffectedItems.Subjectcontains
sign-in
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)

Sigma 1 rule

Elastic 1 rule

Splunk 7 rules