Detection rules › Sublime MQL

Link: Landing page with search-ms protocol redirect

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

Detects messages containing URL shortener links that redirect to search-ms protocol queries, which can be used to execute local file searches on Windows systems.

Threat classification

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

CategoryValues
Attack typesMalware/Ransomware
Tactics and techniquesEvasion, Scripting

Event coverage

Rule body MQL

type.inbound
and all(body.links, .href_url.domain.root_domain in $url_shorteners)
and any(body.links,
        regex.icontains(ml.link_analysis(., mode="aggressive").final_dom.raw,
                        'search-ms:[^\;]*query=[^\;]+\.lnk'
        )
)

Detection logic

Scope: inbound message.

Detects messages containing URL shortener links that redirect to search-ms protocol queries, which can be used to execute local file searches on Windows systems.

  1. inbound message
  2. all of body.links where:
    • .href_url.domain.root_domain in $url_shorteners
  3. any of body.links where:
    • ml.link_analysis(., mode='aggressive').final_dom.raw matches 'search-ms:[^\\;]*query=[^\\;]+\\.lnk'

Inspects: body.links, body.links[].href_url.domain.root_domain, type.inbound. Sensors: ml.link_analysis, regex.icontains. Reference lists: $url_shorteners.

Indicators matched (1)

FieldMatchValue
regex.icontainsregexsearch-ms:[^\;]*query=[^\;]+\.lnk