Detection rules › Sublime MQL
Attachment: HTML smuggling with setTimeout
Recursively scans files and archives to detect HTML smuggling techniques.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Credential Phishing, Malware/Ransomware |
| Tactics and techniques | Evasion, HTML smuggling, Scripting |
Event coverage
| Message attribute |
|---|
| attachments (collection) |
| type |
Rule body MQL
type.inbound
and any(attachments,
.size <= 400
and (
.file_extension in~ ("html", "htm", "shtml", "dhtml")
or .file_extension in~ $file_extensions_common_archives
or .file_type == "html"
)
and any(file.explode(.),
"setTimeout" in .scan.javascript.identifiers
and any(.scan.strings.strings,
strings.ilike(., "*location.href*")
)
)
)
Detection logic
Scope: inbound message.
Recursively scans files and archives to detect HTML smuggling techniques.
- inbound message
any of
attachmentswhere all hold:- .size ≤ 400
any of:
- .file_extension in ('html', 'htm', 'shtml', 'dhtml')
- .file_extension in $file_extensions_common_archives
- .file_type is 'html'
any of
file.explode(.)where all hold:- .scan.javascript.identifiers contains 'setTimeout'
any of
.scan.strings.stringswhere:- . matches '*location.href*'
Inspects: attachments[].file_extension, attachments[].file_type, attachments[].size, type.inbound. Sensors: file.explode, strings.ilike. Reference lists: $file_extensions_common_archives.
Indicators matched (7)
| Field | Match | Value |
|---|---|---|
attachments[].file_extension | member | html |
attachments[].file_extension | member | htm |
attachments[].file_extension | member | shtml |
attachments[].file_extension | member | dhtml |
attachments[].file_type | equals | html |
file.explode(attachments[])[].scan.javascript.identifiers | contains | setTimeout |
strings.ilike | substring | *location.href* |