Detection rules › Sublime MQL
Attachment with auto-opening VBA macro (unsolicited)
Recursively scans files and archives to detect embedded VBA files with an auto open exec.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Malware/Ransomware |
| Tactics and techniques | Macros |
Event coverage
| Message attribute |
|---|
| attachments (collection) |
| type |
Rule body MQL
type.inbound
and any(attachments,
(
.file_extension in~ $file_extensions_macros
or .file_extension in~ $file_extensions_common_archives
or (
.file_extension is null
and .file_type == "unknown"
and .content_type == "application/octet-stream"
and .size < 100000000
)
)
and any(file.explode(.), any(.scan.vba.auto_exec, . == "AutoOpen"))
)
and (
not profile.by_sender().solicited
or (
profile.by_sender().any_messages_malicious_or_spam
and not profile.by_sender().any_messages_benign
)
)
Detection logic
Scope: inbound message.
Recursively scans files and archives to detect embedded VBA files with an auto open exec.
- inbound message
any of
attachmentswhere all hold:any of:
- .file_extension in $file_extensions_macros
- .file_extension in $file_extensions_common_archives
all of:
- .file_extension is missing
- .file_type is 'unknown'
- .content_type is 'application/octet-stream'
- .size < 100000000
any of
file.explode(.)where:any of
.scan.vba.auto_execwhere:- . is 'AutoOpen'
any of:
not:
- profile.by_sender().solicited
all of:
- profile.by_sender().any_messages_malicious_or_spam
not:
- profile.by_sender().any_messages_benign
Inspects: attachments[].content_type, attachments[].file_extension, attachments[].file_type, attachments[].size, type.inbound. Sensors: file.explode, profile.by_sender. Reference lists: $file_extensions_common_archives, $file_extensions_macros.
Indicators matched (3)
| Field | Match | Value |
|---|---|---|
attachments[].file_type | equals | unknown |
attachments[].content_type | equals | application/octet-stream |
file.explode(attachments[])[].scan.vba.auto_exec[] | equals | AutoOpen |