Detection rules › Sublime MQL

Attachment: PowerPoint with suspicious hyperlink

Severity
high
Type
rule
Source
github.com/sublime-security/sublime-rules

Attached PowerPoint contains a suspicious hyperlink that can execute arbitrary code.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesMalware/Ransomware
Tactics and techniquesEvasion, Scripting

Event coverage

Rule body MQL

type.inbound
and any(attachments,
        (.file_extension in~ ("ppt", "pptx"))
        and any(file.explode(.),
                any(.scan.exiftool.fields,
                    .key == "Hyperlinks"
                    and (
                      4 of (
                        strings.ilike(.value, "*[Convert]::ToChar*"),
                        strings.ilike(.value, "*vbs*"),
                        strings.ilike(.value, "*[IO.File]::Create*"),
                        strings.ilike(.value, "*[IO.File]::Exists*"),
                        strings.ilike(.value,
                                      "*[io.FileOPtions]::DeleteOnClose*"
                        ),
                        strings.ilike(.value, "*Net.WebClient*"),
                        strings.ilike(.value, "*dll*"),
                      )
                    )
                )
        )
)

Detection logic

Scope: inbound message.

Attached PowerPoint contains a suspicious hyperlink that can execute arbitrary code.

  1. inbound message
  2. any of attachments where all hold:
    • .file_extension in ('ppt', 'pptx')
    • any of file.explode(.) where:
      • any of .scan.exiftool.fields where all hold:
        • .key is 'Hyperlinks'
        • at least 4 of 7: .value matches any of 7 patterns
          • *[Convert]::ToChar*
          • *vbs*
          • *[IO.File]::Create*
          • *[IO.File]::Exists*
          • *[io.FileOPtions]::DeleteOnClose*
          • *Net.WebClient*
          • *dll*

Inspects: attachments[].file_extension, type.inbound. Sensors: file.explode, strings.ilike.

Indicators matched (10)

FieldMatchValue
attachments[].file_extensionmemberppt
attachments[].file_extensionmemberpptx
file.explode(attachments[])[].scan.exiftool.fields[].keyequalsHyperlinks
strings.ilikesubstring*[Convert]::ToChar*
strings.ilikesubstring*vbs*
strings.ilikesubstring*[IO.File]::Create*
strings.ilikesubstring*[IO.File]::Exists*
strings.ilikesubstring*[io.FileOPtions]::DeleteOnClose*
strings.ilikesubstring*Net.WebClient*
strings.ilikesubstring*dll*