• Sublime Core Feed
Medium Severity

Open redirect (go2.aspx) leading to Microsoft credential phishing

Description

This rule is designed to detect credential phishing attacks that exploit go2.aspx redirects and masquerade as Microsoft-related emails.

References

No references.

Sublime Security
Created Aug 17th, 2023 • Last updated Dec 10th, 2025
Source
type.inbound

// url path ends with go2.aspx
and any(body.links,
        strings.ends_with(.href_url.path, "go2.aspx")

        // query params from href_url or ml.link_analysis contain a redirection string ending with a base64
        // pattern intended to capture an encoded email passed as an additional parameter
        and (
          regex.contains(.href_url.query_params,
                         '[a-z]=[a-z0-9-]+\.[a-z]{2,3}.+[A-Za-z0-9+/=]$|=[^=]$|={3,}$'
          )
          or regex.icontains(ml.link_analysis(.).effective_url.query_params,
                             '[a-z]=[a-z0-9-]+\.[a-z]{2,3}.+[A-Za-z0-9+/=]$|=[^=]$|={3,}$'
          )
        )
)
and headers.mailer is null
and regex.icontains(body.html.inner_text, '(i\x{034F}c\x{034F}r\x{034F}os\x{034F}of\x{034F}|icrosof)|(office|o)\s?365')
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