• Sublime Core Feed
Medium Severity

Link: Multistage Landing - Ludus Presentation

Labels

Credential Phishing
Evasion
Social engineering
Impersonation: Brand
Header analysis
URL analysis
Computer Vision
URL screenshot
Natural Language Understanding
Optical Character Recognition
Sender analysis

Description

Detects when a standalone Ludus document link contains embedded links that are suspicious, particularly those targeting Microsoft services through various evasion techniques. The rule analyzes both the presentation content and linked destinations for suspicious patterns and redirects.

References

No references.

Sublime Security
Created May 14th, 2025 • Last updated May 14th, 2025
Feed Source
Sublime Core Feed
Source
GitHub
type.inbound
// only one link to Ludus
and length(distinct(filter(body.links,
                           .href_url.domain.root_domain in ("ludus.one")
                    ),
                    .href_url.url
           )
) == 1
and any(body.links,
        .href_url.domain.root_domain in ("ludus.one")
        and (
          any(ml.link_analysis(.).final_dom.links,
              .href_url.domain.root_domain != "ludus.com"
              // once we have additional responses, add # of slides == 1 logic
              and (
                .href_url.domain.tld in $suspicious_tlds
                or .href_url.domain.domain in $free_subdomain_hosts
                or .href_url.domain.root_domain in $free_subdomain_hosts
                // observed pattern in credential theft URLs
                or strings.ilike(.href_url.path,
                                 "*o365*",
                                 "*office365*",
                                 "*microsoft*"
                )
                // observed pattern in credential theft URLs
                or strings.ilike(.href_url.query_params,
                                 "*o365*",
                                 "*office365*",
                                 "*microsoft*"
                )
                // observed pattern in credential theft URLs
                or any(beta.scan_base64(.href_url.query_params),
                       strings.ilike(., "*o365*", "*office365*", "*microsoft*")
                )
                or ml.link_analysis(.href_url, mode="aggressive").credphish.disposition == "phishing"
                or ml.link_analysis(.href_url, mode="aggressive").credphish.contains_captcha
                or strings.icontains(ml.link_analysis(.href_url,
                                                      mode="aggressive"
                                     ).final_dom.display_text,
                                     "I'm Human"
                )
                // bails out to a well-known domain, seen in evasion attempts
                or (
                  length(ml.link_analysis(.href_url, mode="aggressive").redirect_history
                  ) > 0
                  and ml.link_analysis(.href_url, mode="aggressive").effective_url.domain.root_domain in $tranco_10k
                )
              )
          )
          // credential theft language on the main Scribd page
          or any(ml.nlu_classifier(beta.ocr(ml.link_analysis(.,
                                                             mode="aggressive"
                                            ).screenshot
                                   ).text
                 ).intents,
                 .name == "cred_theft" and .confidence != "low"
          )
        )
)
// negate highly trusted sender domains unless they fail DMARC authentication
and (
  (
    sender.email.domain.root_domain in $high_trust_sender_root_domains
    and not headers.auth_summary.dmarc.pass
  )
  or sender.email.domain.root_domain not in $high_trust_sender_root_domains
)
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