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Update link_microsoft_low_reputation.yml #3425

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Merged
peterdj45 merged 3 commits into from
Nov 8, 2025
Merged

Update link_microsoft_low_reputation.yml #3425

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bc814a1
Update link_microsoft_low_reputation.yml
peterdj45 Oct 21, 2025
3b0b60a
Change suspicious TLD check to specifically 'ru'
peterdj45 Nov 7, 2025
873d272
Merge branch 'main' into peter.fn.link_microsoft_low_rep
peterdj45 Nov 8, 2025
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27 changes: 21 additions & 6 deletions detection-rules/link_microsoft_low_reputation.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -8,12 +8,25 @@ source: |
// suspicious link
and any(body.links,
(
.href_url.domain.root_domain not in $tranco_1m
.href_url.domain.tld == "ru"
or .href_url.domain.root_domain not in $tranco_1m
or .href_url.domain.domain in $free_file_hosts
or .href_url.domain.root_domain in $free_file_hosts
or .href_url.domain.root_domain in $free_subdomain_hosts
or .href_url.domain.domain in $url_shorteners
or .href_url.domain.domain in $social_landing_hosts
// account for URL rewrites
or (
any(.href_url.query_params_decoded["domain"],
strings.parse_domain(.).tld == "ru"
or strings.parse_domain(.).root_domain not in~ $tranco_1m
or strings.parse_domain(.).domain in~ $free_file_hosts
or strings.parse_domain(.).root_domain in~ $free_file_hosts
or strings.parse_domain(.).root_domain in~ $free_subdomain_hosts
or strings.parse_domain(.).domain in~ $url_shorteners
or strings.parse_domain(.).domain in~ $social_landing_hosts
)
)
or

// mass mailer link, masks the actual URL
Expand Down Expand Up @@ -49,7 +62,6 @@ source: |
"microsoft.com",
"aka.ms",
"msftauthimages.net",
"mimecastprotect.com",
"office.com",
"microsoftproject.com"
)
Expand All @@ -71,13 +83,16 @@ source: |
.file_type in $file_types_images
and any(ml.logo_detect(.).brands, strings.starts_with(.name, "Microsoft"))
)
or strings.istarts_with(strings.replace_confusables(body.current_thread.text), "Microsoft ")
or strings.istarts_with(strings.replace_confusables(body.current_thread.text),
"Microsoft "
)
or (
regex.imatch(strings.replace_confusables(body.current_thread.text),
'[\n\s]*[o0O]ff[il1]ce\b.*'
)
and not regex.icontains(strings.replace_confusables(body.current_thread.text),
'office (for lease|rent|sale)'
and not regex.icontains(strings.replace_confusables(body.current_thread.text
),
'office (for lease|rent|sale)'
)
)
or any(ml.logo_detect(file.message_screenshot()).brands,
Expand Down Expand Up @@ -253,7 +268,7 @@ source: |
"*renewal*"
)
)

or (
any(attachments,
.file_type in $file_types_images
Expand Down
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