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High Severity

Attachment: Potential sandbox evasion in Office file

Description

Scans attached files with known Office file extension, and alerts on the presence of strings indicative of sandbox evasion checks.

Malicious code may carry out checks against the local host (e.g. running processes, disk size, domain-joined status) before running its final payload.

@ajpc500
Created Aug 17th, 2023 • Last updated Aug 5th, 2025
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 any(file.explode(.),
                1 of (
                  any(.scan.strings.strings, strings.ilike(., "*Win32_Processor*")),
                  any(.scan.strings.strings, strings.ilike(., "*Win32_LogicalDisk*")),
                  any(.scan.strings.strings, strings.ilike(., "*Win32_ComputerSystem*")),
                  any(.scan.strings.strings, strings.ilike(., "*Win32_Process*")),
                  any(.scan.strings.strings, strings.ilike(., "*LDAP://RootDSE*"))
                )
        )
)
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