DLP: EU Debit Card Number

Severity: high
Type: dlp
Source: github.com/sublime-security/sublime-rules

Detects messages containing European debit card numbers.

Event coverage

Message attribute
attachments (collection)
sender.email
type

Rule body MQL

type.outbound
and any(attachments,
        (
          .file_extension in~ $file_extensions_common_archives
          or .file_extension in~ ('.csv', '.txt', '.xlsx', '.xls')
        )
        and any(file.explode(.),
                // Debit card: 13-19 digits with optional spaces/hyphens
                regex.contains(.scan.ocr.raw, '\b(?:\d{4}[\s\-]?){3}\d{1,7}\b')
        )
)
and (
  // EU country TLDs
  strings.icontains(sender.email.domain.tld, "at")
  or strings.icontains(sender.email.domain.tld, "be")
  or strings.icontains(sender.email.domain.tld, "bg")
  or strings.icontains(sender.email.domain.tld, "hr")
  or strings.icontains(sender.email.domain.tld, "cy")
  or strings.icontains(sender.email.domain.tld, "cz")
  or strings.icontains(sender.email.domain.tld, "dk")
  or strings.icontains(sender.email.domain.tld, "ee")
  or strings.icontains(sender.email.domain.tld, "fi")
  or strings.icontains(sender.email.domain.tld, "fr")
  or strings.icontains(sender.email.domain.tld, "de")
  or strings.icontains(sender.email.domain.tld, "gr")
  or strings.icontains(sender.email.domain.tld, "hu")
  or strings.icontains(sender.email.domain.tld, "ie")
  or strings.icontains(sender.email.domain.tld, "it")
  or strings.icontains(sender.email.domain.tld, "lv")
  or strings.icontains(sender.email.domain.tld, "lt")
  or strings.icontains(sender.email.domain.tld, "lu")
  or strings.icontains(sender.email.domain.tld, "mt")
  or strings.icontains(sender.email.domain.tld, "nl")
  or strings.icontains(sender.email.domain.tld, "pl")
  or strings.icontains(sender.email.domain.tld, "pt")
  or strings.icontains(sender.email.domain.tld, "ro")
  or strings.icontains(sender.email.domain.tld, "sk")
  or strings.icontains(sender.email.domain.tld, "si")
  or strings.icontains(sender.email.domain.tld, "es")
  or strings.icontains(sender.email.domain.tld, "se")
  or strings.icontains(sender.email.domain.tld, "eu")
)

Detection logic

Scope: outbound message.

Detects messages containing European debit card numbers.

outbound message
any of attachments where all hold:
- any of:
  - .file_extension in $file_extensions_common_archives
  - .file_extension in ('.csv', '.txt', '.xlsx', '.xls')
- any of file.explode(.) where:
  - .scan.ocr.raw matches '\\b(?:\\d{4}[\\s\\-]?){3}\\d{1,7}\\b'
sender.email.domain.tld contains any of 28 patterns
- at
- be
- bg
- hr
- cy
- cz
- dk
- ee
- fi
- fr
- de
- gr
- hu
- ie
- it
- lv
- lt
- lu
- mt
- nl
- pl
- pt
- ro
- sk
- si
- es
- se
- eu

Inspects: attachments[].file_extension, sender.email.domain.tld, type.outbound. Sensors: file.explode, regex.contains, strings.icontains. Reference lists: $file_extensions_common_archives.

Indicators matched (33)

Field	Match	Value
`attachments[].file_extension`	member	`.csv`
`attachments[].file_extension`	member	`.txt`
`attachments[].file_extension`	member	`.xlsx`
`attachments[].file_extension`	member	`.xls`
`regex.contains`	regex	`\b(?:\d{4}[\s\-]?){3}\d{1,7}\b`
`strings.icontains`	substring	`at`
`strings.icontains`	substring	`be`
`strings.icontains`	substring	`bg`
`strings.icontains`	substring	`hr`
`strings.icontains`	substring	`cy`
`strings.icontains`	substring	`cz`
`strings.icontains`	substring	`dk`

21 more

`strings.icontains`	substring	`ee`
`strings.icontains`	substring	`fi`
`strings.icontains`	substring	`fr`
`strings.icontains`	substring	`de`
`strings.icontains`	substring	`gr`
`strings.icontains`	substring	`hu`
`strings.icontains`	substring	`ie`
`strings.icontains`	substring	`it`
`strings.icontains`	substring	`lv`
`strings.icontains`	substring	`lt`
`strings.icontains`	substring	`lu`
`strings.icontains`	substring	`mt`
`strings.icontains`	substring	`nl`
`strings.icontains`	substring	`pl`
`strings.icontains`	substring	`pt`
`strings.icontains`	substring	`ro`
`strings.icontains`	substring	`sk`
`strings.icontains`	substring	`si`
`strings.icontains`	substring	`es`
`strings.icontains`	substring	`se`
`strings.icontains`	substring	`eu`

`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)

DLP: EU Debit Card Number

Event coverage

Rule body MQL

Detection logic

Indicators matched (33)

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