High Severity
Attachment: HTML file with reference to recipient and suspicious patterns
Description
Attached HTML file (or HTML file within an attached email) contains references to the recipients email address, indicative of credential phishing, and suspicious Javascript patterns.
References
No references.
Sublime Security
Created Aug 17th, 2023 • Last updated May 3rd, 2024
Feed Source
Sublime Core Feed
Source
type.inbound
and any(attachments,
(
.content_type == "text/html"
or .content_type == "message/rfc822"
or .file_extension in~ ("html", "htm", "shtml", "dhtml")
or .file_type == "html"
)
and any(file.explode(.),
.flavors.mime in~ ("text/html", "text/plain")
and any(recipients.to,
any(..scan.strings.strings,
strings.icontains(., ..email.email)
)
and (.email.domain.valid or strings.icontains(.display_name, "undisclosed"))
)
)
and any(file.explode(.),
(
any(.flavors.yara, . == "javascript_file")
// common indicator of HTML smuggling
and length(filter(.scan.javascript.identifiers, strings.ilike(., "_0x*"))) > 50
)
or (
// javascript that doesn't get pulled out properly
.flavors.mime == "text/plain"
and strings.ilike(.file_name, "script*")
// common indicator of HTML smuggling
and length(filter(.scan.strings.strings, regex.imatch(., ".*_0x.*"))) > 50
)
)
)
Playground
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