Suspected WordPress abuse with cross-site scripting (XSS) indicators

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

Detects inbound messages from likely compromised WordPress sites that exhibit indicators of cross-site scripting (XSS) attempts. The rule identifies potential script injection patterns within message bodies and/or subjects containing multiple suspicious JavaScript-related keywords or indicators.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

Category	Values
Attack types	Malware/Ransomware, Credential Phishing
Tactics and techniques	Scripting, Impersonation: Brand, Social engineering

Event coverage

Message attribute
body.current_thread
sender.email
subject
type

Rule body MQL

type.inbound
and sender.email.local_part == "wordpress"
and (
  regex.icontains(body.current_thread.text,
                  'document\.createElement.{0,9}script'
  )
  or 2 of (
    strings.icount(subject.subject, "script") > 1,
    strings.count(subject.subject, '%') >= 4,
    strings.count(subject.subject, '\') >= 3,
    strings.count(subject.subject, "/") >= 3,
    strings.icontains(subject.subject, "xss"),
    strings.contains(subject.subject, "CharCode"),
    strings.contains(subject.subject, 'onload'),
    strings.contains(subject.subject, 'fetch('),
    strings.contains(subject.subject, "OnFocus="),
    strings.contains(subject.subject, 'javascript:fetch'),
    strings.icontains(subject.subject, "src="),
    strings.icontains(subject.subject, "iframe"),
    strings.icontains(subject.subject, "embed"),
    strings.icontains(subject.subject, "object"),
    strings.icontains(subject.subject, "onerror"),
    strings.icontains(subject.subject, "onclick"),
    strings.icontains(subject.subject, "onmouseover"),
    strings.icontains(subject.subject, "onmouseout"),
    strings.icontains(subject.subject, "onkeydown"),
    strings.icontains(subject.subject, "onkeypress"),
    strings.icontains(subject.subject, "onkeyup"),
    strings.icontains(subject.subject, "onchange"),
    strings.icontains(subject.subject, "oninput"),
    strings.icontains(subject.subject, "onsubmit"),
    regex.icontains(subject.subject, 'eval\b'),
    strings.icontains(subject.subject, "alert"),
    strings.icontains(subject.subject, "document.cookie"),
    strings.icontains(subject.subject, "document.write"),
    strings.icontains(subject.subject, "window.location"),
    strings.icontains(subject.subject, "setTimeout"),
    strings.icontains(subject.subject, "setInterval"),
    strings.icontains(subject.subject, "atob"),
    strings.icontains(subject.subject, "innerHTML"),
    strings.icontains(subject.subject, "outerHTML"),
    strings.icontains(subject.subject, "XMLHttpRequest"),
    regex.icontains(subject.subject, 'import\b'),
    strings.icontains(subject.subject, "execCommand")
  )
)

Detection logic

Scope: inbound message.

inbound message
sender.email.local_part is 'wordpress'
any of:
- body.current_thread.text matches 'document\\.createElement.{0,9}script'
- at least 2 of:
  - strings.icount(subject.subject, 'script') > 1
  - strings.count(subject.subject, '%') ≥ 4
  - strings.count(subject.subject, '\\') ≥ 3
  - strings.count(subject.subject, '/') ≥ 3
  - subject.subject contains 'xss'
  - subject.subject contains 'CharCode'
  - subject.subject contains 'onload'
  - subject.subject contains 'fetch('
  - subject.subject contains 'OnFocus='
  - subject.subject contains 'javascript:fetch'
  - subject.subject contains 'src='
  - subject.subject contains 'iframe'
  - subject.subject contains 'embed'
  - subject.subject contains 'object'
  - subject.subject contains 'onerror'
  - subject.subject contains 'onclick'
  - subject.subject contains 'onmouseover'
  - subject.subject contains 'onmouseout'
  - subject.subject contains 'onkeydown'
  - subject.subject contains 'onkeypress'
  - subject.subject contains 'onkeyup'
  - subject.subject contains 'onchange'
  - subject.subject contains 'oninput'
  - subject.subject contains 'onsubmit'
  - subject.subject matches 'eval\\b'
  - subject.subject contains 'alert'
  - subject.subject contains 'document.cookie'
  - subject.subject contains 'document.write'
  - subject.subject contains 'window.location'
  - subject.subject contains 'setTimeout'
  - subject.subject contains 'setInterval'
  - subject.subject contains 'atob'
  - subject.subject contains 'innerHTML'
  - subject.subject contains 'outerHTML'
  - subject.subject contains 'XMLHttpRequest'
  - subject.subject matches 'import\\b'
  - subject.subject contains 'execCommand'

Inspects: body.current_thread.text, sender.email.local_part, subject.subject, type.inbound. Sensors: regex.icontains, strings.contains, strings.count, strings.icontains, strings.icount.

Indicators matched (35)

Field	Match	Value
`sender.email.local_part`	equals	`wordpress`
`regex.icontains`	regex	`document\.createElement.{0,9}script`
`strings.icontains`	substring	`xss`
`strings.contains`	substring	`CharCode`
`strings.contains`	substring	`onload`
`strings.contains`	substring	`fetch(`
`strings.contains`	substring	`OnFocus=`
`strings.contains`	substring	`javascript:fetch`
`strings.icontains`	substring	`src=`
`strings.icontains`	substring	`iframe`
`strings.icontains`	substring	`embed`
`strings.icontains`	substring	`object`

23 more

`strings.icontains`	substring	`onerror`
`strings.icontains`	substring	`onclick`
`strings.icontains`	substring	`onmouseover`
`strings.icontains`	substring	`onmouseout`
`strings.icontains`	substring	`onkeydown`
`strings.icontains`	substring	`onkeypress`
`strings.icontains`	substring	`onkeyup`
`strings.icontains`	substring	`onchange`
`strings.icontains`	substring	`oninput`
`strings.icontains`	substring	`onsubmit`
`regex.icontains`	regex	`eval\b`
`strings.icontains`	substring	`alert`
`strings.icontains`	substring	`document.cookie`
`strings.icontains`	substring	`document.write`
`strings.icontains`	substring	`window.location`
`strings.icontains`	substring	`setTimeout`
`strings.icontains`	substring	`setInterval`
`strings.icontains`	substring	`atob`
`strings.icontains`	substring	`innerHTML`
`strings.icontains`	substring	`outerHTML`
`strings.icontains`	substring	`XMLHttpRequest`
`regex.icontains`	regex	`import\b`
`strings.icontains`	substring	`execCommand`

`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)