• Sublime Core Feed
High Severity

Attachment: HTML smuggling 'body onload' linking to suspicious destination

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Description

Potential HTML Smuggling.

This rule inspects HTML attachments that contain a single link and leveraging an HTML body onload event. The linked domain must be in the URLhaus trusted repoters list, or have a suspicious TLD.

References

No references.

Sublime Security
Created Sep 21st, 2023 • Last updated Sep 22nd, 2023
Feed Source
Sublime Core Feed
Source
GitHub
type.inbound
and any(attachments,
        (
          .file_extension in~ ("html", "htm", "shtml", "dhtml", "xhtml")
          or (
            .file_extension is null
            and .file_type == "unknown"
            and .content_type == "application/octet-stream"
          )
          or .file_extension in~ $file_extensions_common_archives
          or .file_type == "html"
          or .content_type == "text/html"
        )
        and any(file.explode(.),
                not length(.scan.url.invalid_urls) > 0
                and length(.scan.url.urls) == 1
                and any(.scan.strings.strings, strings.ilike(., "*body onload*"))
                and (
                  any(.scan.url.urls,
                      .domain.root_domain in $abuse_ch_urlhaus_domains_trusted_reporters
                      
                      // To-do uncomment below when list is created
                      //or .domain.root_domain in $suspicious_root_domains
                      or .domain.tld in $suspicious_tlds
                  )
                )
        )
)

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