MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Rule body
id: 506291dd-8050-4c98-a92f-58e376080a0a
name: Cisco SEG - Suspicious link
description: |
'Detects mails with suspicious links.'
severity: High
status: Available
requiredDataConnectors:
- connectorId: CefAma
dataTypes:
- CommonSecurityLog
queryFrequency: 15m
queryPeriod: 15m
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1566
query: |
let bl_cat = dynamic(['Adult', 'Hacking', 'Cheating and Plagiarism', 'Child Abuse Content', 'Dating', 'Illegal Activities', 'Pornography']);
CiscoSEGEvent
| where NetworkDirection =~ 'Incoming'
| where tostring(AdditionalFields) has 'ESAURLDetails'
| extend link_cat = extract(@"'Category': '(.*?)'", 1, tostring(AdditionalFields))
| where link_cat in~ (bl_cat)
| extend AccountCustomEntity = DstUserName
entityMappings:
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
version: 1.0.3
kind: Scheduled
Stages and Predicates
Parameters
let bl_cat = dynamic(['Adult', 'Hacking', 'Cheating and Plagiarism', 'Child Abuse Content', 'Dating', 'Illegal Activities', 'Pornography']);
Stage 1: source
CiscoSEGEvent
Stage 2: where
| where NetworkDirection =~ 'Incoming'
Stage 3: where
| where tostring(AdditionalFields) has 'ESAURLDetails'
Stage 4: extend
| extend link_cat = extract(@"'Category': '(.*?)'", 1, tostring(AdditionalFields))
Stage 5: where
| where link_cat in~ (bl_cat)
Stage 6: extend
| extend AccountCustomEntity = DstUserName
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
AdditionalFields | match |
| field:"AdditionalFields" kind:match value:"ESAURLDetails" |
NetworkDirection | eq |
| field:"NetworkDirection" kind:eq value:"Incoming" |
link_cat | in |
| field:"link_cat" kind:in |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
link_cat | extend |
AccountCustomEntity | extend |