O365_Exchange_SetMailBox_GrantSendOnBehalf_External
ID: 100438
Description:
Set-Mailbox GrantSendOnBehalf on an Exchange Mailbox External Address - KLK - This behavior identifies a case where the Grant SendOnBehalf permission has been set to an address that is external to the domain. For example, an external user has the ability to send e-mail on behalf of a domain user. This also identifies when multiple SendOnBehalf operations have been set (multiple mailboxes).
Repository: Fluency Group: Office365 Type: event
Default Status:
Enabled
Tags: | |||
---|---|---|---|
O365 | Office | Exchange | Mailbox |
Selector:
Query:
Filters:
Standard:
Field | MUST hit |
---|---|
@fields.Operation | Set-Mailbox |
@fields.Workload | Exchange |
Field | MUST NOT hit |
---|---|
@fields.ExternalAccess | false |
Additional JSON:
function json_doc_filter (doc)
for i,v in ipairs(doc['@fields'].Parameters)
do
print(v.Name .. ": " .. v.Value)
if v.Name == "GrantSendOnBehalfTo" then
return true
end
end
return false
end
return json_doc_filter
Behavior Rule:
Key | Type | Behavior Category |
---|---|---|
@fields.UserId | username | application activity |
Risks:
Risks | Base Score | Dimension |
---|---|---|
ALERT_NORMAL | 100 | alert |
Attributes:
Alias | Key |
---|---|
IP | @fields.ClientIP |
ObjectId | @fields.ObjectId |
Operation | @fields.Operation |
ISP | @fields._ip.isp |
City | @fields._ip.city |
Country | @fields._ip.country |
UserId | @fields.UserId |
ExternalAccess | @fields.ExternalAccess |
GrantTo | @fields.ParametersFields.GrantSendOnBehalfTo |
Correlation Rules:
Aggregation:
Name | Window | Field | AggType | Match |
---|---|---|---|---|
MultipleMailboxes | 1 day | @fields.ObjectId | cardinality | gt 1 |
Risks: | ALERT_NORMAL |
First Occurrence:
Name | Window | Fields |
---|---|---|
NewUser | 30 days | @fields.UserId |
Risks: | ML_NEW_USER | |
NewTarget | 30 days | @fields.ObjectId |
Risks: | ML_NEW_USER |
History:
User | Date |
---|---|
ke*y@fluencysecurity.com | 2021 Aug 16 07:07:46 EDT |
ke*y@fluencysecurity.com | 2021 Aug 27 08:14:03 EDT |
ke*y@fluencysecurity.com | 2021 Aug 27 08:14:17 EDT |
ke*y@fluencysecurity.com | 2021 Aug 27 08:16:24 EDT |
ke*y@fluencysecurity.com | 2022 Feb 18 01:08:08 EST |
This page was automatically created/formatted on Wed, 2022 May 4 21:43:53 EDT, from rule_dump.json (4d88bffdfb1cea26b3985f2193033606)