SlackAudit - Public link created for file which can contain sensitive information

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Id	279316e8-8965-47d2-9788-b94dc352c853
Rulename	SlackAudit - Public link created for file which can contain sensitive information.
Description	Detects public links created for files that may contain sensitive data such as passwords, authentication tokens, secret keys, or private configuration files. Tune exclusions using the SlackAuditSensitiveFile_Allowlist_File and SlackAuditSensitiveFile_Allowlist_Account watchlists when known benign files or accounts generate expected public-link activity.
Severity	Medium
Tactics	Exfiltration
Techniques	T1048 T1567.002
Required data connectors	SlackAuditAPI
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/SlackAudit/Analytic Rules/SlackAuditSensitiveFile.yaml
Version	1.0.1
Arm template	279316e8-8965-47d2-9788-b94dc352c853.json

KQL

let AllowedFiles = toscalar(_GetWatchlist('SlackAuditSensitiveFile_Allowlist_File') | summarize make_set(tostring(SearchKey)));
let AllowedUsers = toscalar(_GetWatchlist('SlackAuditSensitiveFile_Allowlist_Account') | summarize make_set(tostring(SearchKey)));
SlackAudit
| where Action =~ 'file_public_link_created'
| extend FileNameLower = tolower(EntityFileName), UserLower = tolower(SrcUserName)
| where EntityFileName in~ ('id_rsa')
    or FileNameLower has_any ('password', 'secret', 'token', 'credential', 'private key', 'api key')
    or FileNameLower has_any ('.ssh', '.npmrc', '.muttrc', '.gitconfig', '.netrc', 'package.json', 'Gemfile', 'bower.json', 'config.gypi', 'travis.yml', 'config.json')
| where isempty(AllowedFiles) or EntityFileName !in~ (AllowedFiles)
| where isempty(AllowedUsers) or UserLower !in~ (AllowedUsers)
| extend AccountCustomEntity = SrcUserName
| extend IPCustomEntity = SrcIpAddr

YAML

entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
tactics:
- Exfiltration
requiredDataConnectors:
- dataTypes:
  - SlackAudit_CL
  connectorId: SlackAuditAPI
alertDetailsOverride:
  alertDisplayNameFormat: Slack public link created for sensitive file {{EntityFileName}} by {{SrcUserName}}
  alertDescriptionFormat: Public link created for {{EntityFileName}} by {{SrcUserName}} from {{SrcIpAddr}}
id: 279316e8-8965-47d2-9788-b94dc352c853
severity: Medium
status: Available
customDetails:
  Action: Action
  SourceIP: SrcIpAddr
  FileName: EntityFileName
  SourceUser: SrcUserName
  ActorEntity: AccountCustomEntity
  IpEntity: IPCustomEntity
query: |
  let AllowedFiles = toscalar(_GetWatchlist('SlackAuditSensitiveFile_Allowlist_File') | summarize make_set(tostring(SearchKey)));
  let AllowedUsers = toscalar(_GetWatchlist('SlackAuditSensitiveFile_Allowlist_Account') | summarize make_set(tostring(SearchKey)));
  SlackAudit
  | where Action =~ 'file_public_link_created'
  | extend FileNameLower = tolower(EntityFileName), UserLower = tolower(SrcUserName)
  | where EntityFileName in~ ('id_rsa')
      or FileNameLower has_any ('password', 'secret', 'token', 'credential', 'private key', 'api key')
      or FileNameLower has_any ('.ssh', '.npmrc', '.muttrc', '.gitconfig', '.netrc', 'package.json', 'Gemfile', 'bower.json', 'config.gypi', 'travis.yml', 'config.json')
  | where isempty(AllowedFiles) or EntityFileName !in~ (AllowedFiles)
  | where isempty(AllowedUsers) or UserLower !in~ (AllowedUsers)
  | extend AccountCustomEntity = SrcUserName
  | extend IPCustomEntity = SrcIpAddr  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/SlackAudit/Analytic Rules/SlackAuditSensitiveFile.yaml
kind: Scheduled
queryPeriod: 1h
version: 1.0.1
name: SlackAudit - Public link created for file which can contain sensitive information.
queryFrequency: 1h
triggerThreshold: 0
relevantTechniques:
- T1048
- T1567.002
description: |
  'Detects public links created for files that may contain sensitive data such as passwords, authentication tokens,
  secret keys, or private configuration files. Tune exclusions using the SlackAuditSensitiveFile_Allowlist_File and SlackAuditSensitiveFile_Allowlist_Account
  watchlists when known benign files or accounts generate expected public-link activity.'  
triggerOperator: gt

ARM