sublimemediumRule

Attachment with auto-opening VBA macro (unsolicited)

Recursively scans files and archives to detect embedded VBA files with an auto open exec.

MITRE ATT&CK

execution

Detection Query

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
  )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

References

https://threatpost.com/microsoft-outlook-users-targeted-by-gamaredons-new-vba-macro/156484/

Raw Content

name: "Attachment with auto-opening VBA macro (unsolicited)"
description: |
  Recursively scans files and archives to detect embedded VBA files with an auto open exec.
references:
  - "https://threatpost.com/microsoft-outlook-users-targeted-by-gamaredons-new-vba-macro/156484/"
type: "rule"
severity: "medium"
source: |
  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
    )
  )
attack_types:
  - "Malware/Ransomware"
tactics_and_techniques:
  - "Macros"
detection_methods:
  - "Archive analysis"
  - "File analysis"
  - "Macro analysis"
  - "Sender analysis"
id: "d48b3e53-dee4-546b-b81a-0c781929fdfb"