Medium Severity
Attachment: Encrypted Microsoft Office file (unsolicited)
Description
Encrypted OLE2 (eg Microsoft Office) attachment from an unsolicited sender. Attachment encryption is a common technique used to bypass malware scanning products. Use if receiving encrypted attachments is not normal behavior in your environment.
References
Sublime Security
Created Aug 17th, 2023 • Last updated Dec 19th, 2023
Feed Source
Sublime Core Feed
Source
type.inbound
and any(attachments,
(
.file_extension in~ $file_extensions_macros
or (
.file_extension is null
and .file_type == "unknown"
and .content_type == "application/octet-stream"
and .size < 100000000
)
)
and file.oletools(.).indicators.encryption.exists
)
and (
not profile.by_sender().solicited
or (
profile.by_sender().any_messages_malicious_or_spam
and not profile.by_sender().any_false_positives
)
)
Playground
Test against your own EMLs or sample data.