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

Status: available
Severity: medium
Time window: 1h
Source: github.com/Azure/Azure-Sentinel

'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.'

MITRE ATT&CK coverage

Tactic	Techniques
Exfiltration	`T1048` Exfiltration Over Alternative Protocol, `T1567.002` Exfiltration Over Web Service: Exfiltration to Cloud Storage

Rule body kusto

id: 279316e8-8965-47d2-9788-b94dc352c853
name: 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
status: Available
requiredDataConnectors:
  - connectorId: SlackAuditAPI
    dataTypes:
      - SlackAudit_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Exfiltration
relevantTechniques:
  - T1048
  - T1567.002
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
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: AccountCustomEntity
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
alertDetailsOverride:
  alertDisplayNameFormat: Slack public link created for sensitive file {{EntityFileName}} by {{SrcUserName}}
  alertDescriptionFormat: Public link created for {{EntityFileName}} by {{SrcUserName}} from {{SrcIpAddr}}
customDetails:
  FileName: EntityFileName
  Action: Action
  SourceUser: SrcUserName
  SourceIP: SrcIpAddr
  ActorEntity: AccountCustomEntity
  IpEntity: IPCustomEntity
version: 1.0.1
kind: Scheduled

Stages and Predicates

Let binding: `AllowedFiles`

let AllowedFiles = toscalar(_GetWatchlist('SlackAuditSensitiveFile_Allowlist_File') | summarize make_set(tostring(SearchKey)));

Let binding: `AllowedUsers`

let AllowedUsers = toscalar(_GetWatchlist('SlackAuditSensitiveFile_Allowlist_Account') | summarize make_set(tostring(SearchKey)));

Stage 1: `source`

SlackAudit

Stage 2: `where`

| where Action =~ 'file_public_link_created'

Stage 3: `extend`

| extend FileNameLower = tolower(EntityFileName), UserLower = tolower(SrcUserName)

Stage 4: `where`

| 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')

Stage 5: `where`

| where isempty(AllowedFiles) or EntityFileName !in~ (AllowedFiles)

References AllowedFiles (defined above).

Stage 6: `where`

| where isempty(AllowedUsers) or UserLower !in~ (AllowedUsers)

References AllowedUsers (defined above).

Stage 7: `extend`

| extend AccountCustomEntity = SrcUserName

Stage 8: `extend`

| extend IPCustomEntity = SrcIpAddr

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Action`	eq	`file_public_link_created`
`AllowedFiles`	is_null	(no value, null check)
`AllowedUsers`	is_null	(no value, null check)
`EntityFileName`	in	`id_rsa`
`FileNameLower`	match	`.gitconfig` `.muttrc` `.netrc` `.npmrc` `.ssh` `Gemfile` `api key` `bower.json` `config.gypi` `config.json` `credential` `package.json` `password` `private key` `secret` `token` `travis.yml`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`FileNameLower`	`extend`
`UserLower`	`extend`
`AccountCustomEntity`	`extend`
`IPCustomEntity`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

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

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: `AllowedFiles`

Let binding: `AllowedUsers`

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Stage 4: `where`

Stage 5: `where`

Stage 6: `where`

Stage 7: `extend`

Stage 8: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

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

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: AllowedFiles

Let binding: AllowedUsers

Stage 1: source

Stage 2: where

Stage 3: extend

Stage 4: where

Stage 5: where

Stage 6: where

Stage 7: extend

Stage 8: extend

Indicators

Output fields

Let binding: `AllowedFiles`

Let binding: `AllowedUsers`

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Stage 4: `where`

Stage 5: `where`

Stage 6: `where`

Stage 7: `extend`

Stage 8: `extend`