Detection rules › Sublime MQL

Link: Direct link to riddle.com hosted showcase

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

Message contains a single link to a Riddle.com hosted showcase which has been observed abused for credential phishing landing

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesCredential Phishing
Tactics and techniquesFree file host

Event coverage

Rule body MQL

type.inbound
and length(body.links) < 20
and any(body.links, .href_url.domain.root_domain == "riddle.com")
and length(filter(body.links,
                  .href_url.domain.root_domain == "riddle.com"
                  and strings.istarts_with(.href_url.path, '/view/')
           )
) == 1
// 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
)
and not profile.by_sender_email().any_messages_benign

Detection logic

Scope: inbound message.

Message contains a single link to a Riddle.com hosted showcase which has been observed abused for credential phishing landing

  1. inbound message
  2. length(body.links) < 20
  3. any of body.links where:
    • .href_url.domain.root_domain is 'riddle.com'
  4. length(filter(body.links, .href_url.domain.root_domain == 'riddle.com' and strings.istarts_with(.href_url.path, '/view/'))) is 1
  5. any of:
    • all of:
      • sender.email.domain.root_domain in $high_trust_sender_root_domains
      • not:
        • headers.auth_summary.dmarc.pass
    • sender.email.domain.root_domain not in $high_trust_sender_root_domains
  6. not:
    • profile.by_sender_email().any_messages_benign

Inspects: body.links, body.links[].href_url.domain.root_domain, body.links[].href_url.path, headers.auth_summary.dmarc.pass, sender.email.domain.root_domain, type.inbound. Sensors: profile.by_sender_email, strings.istarts_with. Reference lists: $high_trust_sender_root_domains.

Indicators matched (2)

FieldMatchValue
body.links[].href_url.domain.root_domainequalsriddle.com
strings.istarts_withprefix/view/