Detection rules › Sublime MQL

Attachment: SFX archive containing commands

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

Attachment is an SFX archive that contains commands that will execute when opened. This can be used to run malicious commands, and has been observed in the wild.

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~ ("exe", "sfx")
        and any(file.explode(.),
                any(.scan.strings.strings,
                    strings.ilike(.,
                                  'CMT;The comment below contains SFX script commands'
                    )
                )
                and any(.scan.strings.strings, strings.ilike(., 'Setup=*'))
        )
)

Detection logic

Scope: inbound message.

Attachment is an SFX archive that contains commands that will execute when opened. This can be used to run malicious commands, and has been observed in the wild.

  1. inbound message
  2. any of attachments where all hold:
    • .file_extension in ('exe', 'sfx')
    • any of file.explode(.) where all hold:
      • any of .scan.strings.strings where:
        • . matches 'CMT;The comment below contains SFX script commands'
      • any of .scan.strings.strings where:
        • . matches 'Setup=*'

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

Indicators matched (4)

FieldMatchValue
attachments[].file_extensionmemberexe
attachments[].file_extensionmembersfx
strings.ilikesubstringCMT;The comment below contains SFX script commands
strings.ilikesubstringSetup=*