• Sublime Core Feed
Medium Severity

Attachment: Encrypted Microsoft Office file (unsolicited)

Labels

Malware/Ransomware
Encryption
Macros
Scripting
Archive analysis
File analysis
OLE analysis
Sender analysis

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
GitHub
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
  )
)
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