Medium Severity
Brand impersonation: Microsoft with low reputation links
Description
Detects low reputation links with Microsoft specific indicators in the body.
References
No references.
Sublime Security
Created Aug 17th, 2023 • Last updated Dec 18th, 2024
Feed Source
Sublime Core Feed
Source
type.inbound
and 0 < length(body.links) < 50
// suspicious link
and any(body.links,
(
.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
// mass mailer link, masks the actual URL
.href_url.domain.root_domain in (
"hubspotlinks.com",
"mandrillapp.com",
"sendgrid.net",
"rs6.net"
)
// Google AMP redirect
or (
.href_url.domain.sld == "google"
and strings.starts_with(.href_url.path, "/amp/")
)
// Recipient email address in link
or any(body.links,
any(recipients.to,
strings.icontains(..href_url.url, .email.email)
and any(recipients.to, .email.domain.valid)
)
)
or .href_url.domain.root_domain == "beehiiv.com"
)
// exclude sources of potential FPs
and (
.href_url.domain.root_domain not in (
"svc.ms",
"sharepoint.com",
"1drv.ms",
"microsoft.com",
"aka.ms",
"msftauthimages.net",
"mimecastprotect.com",
"office.com",
"microsoftproject.com"
)
or any(body.links, .href_url.domain.domain in $free_file_hosts)
)
and .href_url.domain.root_domain not in $org_domains
and .href_url.domain.valid
)
// not a reply
and (
length(headers.references) == 0
or not any(headers.hops, any(.fields, strings.ilike(.name, "In-Reply-To")))
)
// Microsoft logo
and (
any(attachments,
.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 regex.imatch(strings.replace_confusables(body.current_thread.text), '[\n\s]*[o0O]ff[il1]ce\b.*')
or any(ml.logo_detect(beta.message_screenshot()).brands,
strings.starts_with(.name, "Microsoft")
)
or (
regex.icontains(body.html.raw,
'<table[^>]*>\s*<tbody[^>]*>\s*<tr[^>]*>\s*(<td[^>]*bgcolor="#[0-9A-Fa-f]{6}"[^>]*>\s* \s*</td>\s*){2}\s*</tr>\s*<tr[^>]*>\s*(<td[^>]*bgcolor="#[0-9A-Fa-f]{6}"[^>]*>\s* \s*</td>\s*){2}'
)
or regex.icontains(body.html.raw,
'<td style="background:\s*rgb\(246,\s*93,\s*53\);\s*height:\d+px;">.*?<td style="background:\s*rgb\(129,\s*187,\s*5\);\s*height:\d+px;">.*?<td style="background:\s*rgb\(4,\s*165,\s*240\);\s*height:\d+px;">.*?<td style="background:\s*rgb\(255,\s*186,\s*7\);\s*height:\d+px;">'
)
or 4 of (
regex.icontains(body.html.raw,
'<td style="width:.\d.px;.height:.\d.px;.background-color:.rgb\(245, 189, 67\);">.{0,10}</td>'
),
regex.icontains(body.html.raw,
'<td style="width:.\d.px;.height:.\d.px;.background-color:.rgb\(137, 184, 57\);">.{0,10}</td>'
),
regex.icontains(body.html.raw,
'<td style="width:.\d.px;.height:.\d.px;.background-color:.rgb\(217, 83, 51\);">.{0,10}</td>'
),
regex.icontains(body.html.raw,
'<td style="width:.\d.px;.height:.\d.px;.background-color:.rgb\(71, 160, 218\);">.{0,10}</td>'
)
)
)
or regex.icontains(body.html.raw,
'<table[^>]*>\s*<tbody[^>]*>\s*<tr[^>]*>\s*(<td[^>]*bgcolor="#[0-9A-Fa-f]{6}"[^>]*>\s* \s*</td>\s*){2}\s*</tr>\s*<tr[^>]*>\s*(<td[^>]*bgcolor="#[0-9A-Fa-f]{6}"[^>]*>\s* \s*</td>\s*){2}'
)
or 3 of (
regex.icontains(body.html.raw, '.password-expiration'),
regex.icontains(body.html.raw, 'color: #2672ec;'),
regex.icontains(body.html.raw, 'Microsoft')
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(246,\s?93,\s?53\)'),
regex.icontains(body.html.raw, 'rgb\(129,\s?187,\s?5\)'),
regex.icontains(body.html.raw, 'rgb\(4,\s?165,\s?240\)'),
regex.icontains(body.html.raw, 'rgb\(255,\s?186,\s?7\)'),
)
or 4 of (
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)red'
),
regex.icontains(body.html.raw, 'rgb\(19,\s?186,\s?132\)'),
regex.icontains(body.html.raw, 'rgb\(4,\s?166,\s?240\)'),
regex.icontains(body.html.raw, 'rgb\(255,\s?186,\s?8\)'),
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(245,\s?189,\s?67\)'),
regex.icontains(body.html.raw, 'rgb\(137,\s?184,\s?57\)'),
regex.icontains(body.html.raw, 'rgb\(217,\s?83,\s?51\)'),
regex.icontains(body.html.raw, 'rgb\(71,\s?160,\s?218\)')
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(73,\s?161,\s?232\)'),
regex.icontains(body.html.raw, 'rgb\(224,\s?92,\s?53\)'),
regex.icontains(body.html.raw, 'rgb\(139,\s?183,\s?55\)'),
regex.icontains(body.html.raw, 'rgb\(244,\s?188,\s?65\)')
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(213,\s?56,\s?62\)'),
regex.icontains(body.html.raw, 'rgb\(0,\s?114,\s?30\)'),
regex.icontains(body.html.raw, 'rgb\(0,\s?110,\s?173\)'),
regex.icontains(body.html.raw, 'rgb\(227,\s?209,\s?43\)'),
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(246,\s?93,\s?53\)'),
regex.icontains(body.html.raw, 'rgb\(129,\s?187,\s?5\)'),
regex.icontains(body.html.raw, 'rgb\(4,\s?165,\s?240\)'),
regex.icontains(body.html.raw, 'rgb\(255,\s?186,\s?7\)')
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(242,\s?80,\s?34\)'),
regex.icontains(body.html.raw, 'rgb\(127,\s?186,\s?0\)'),
regex.icontains(body.html.raw, 'rgb\(0,\s?164,\s?239\)'),
regex.icontains(body.html.raw, 'rgb\(255,\s?185,\s?0\)'),
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(243,\s?83,\s?37\)'),
regex.icontains(body.html.raw, 'rgb\(129,\s?188,\s?6\)'),
regex.icontains(body.html.raw, 'rgb\(5,\s?166,\s?240\)'),
regex.icontains(body.html.raw, 'rgb\(255,\s?186,\s?8\)')
)
or 4 of (
regex.icontains(body.html.raw, 'rgb\(243,\s?80,\s?34\)'),
regex.icontains(body.html.raw, 'rgb\(128,\s?187,\s?3\)'),
regex.icontains(body.html.raw, 'rgb\(3,\s?165,\s?240\)'),
regex.icontains(body.html.raw, 'rgb\(255,\s?185,\s?3\)')
)
or 4 of (
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?(#)?(FF1940|eb5024|F25022|FF1941|red)'
),
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?(#)?(36ba57|3eb55d|7db606|7FBA00|36ba58|green)'
),
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?#(04a1d6|04B5F0|05a1e8|00A4EF|01a4ef|04a5f0)'
),
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?#(FFCA07|f7b408|FFB900|FFCA08|ffb901|ffba07)'
),
)
or 4 of (
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?#(f65314|f65d35|49a1e8|E74F23|F35325)'
),
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?#(7cbf42|81bb05|e05c35|7AB206|81BC06)'
),
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?#(00a4ef|0078d7|8bb737|04a5f0|059EE4|05A6F0)'
),
regex.icontains(body.html.raw,
'(background-color:|background:|bgcolor=)(.)?#(ffb900|ffba07|f4bc41|F2B108|FFBA08)'
),
)
// fuzzy approach
or 4 of (
regex.icontains(body.html.raw,
'rgb\((2[1-4][0-9]|250),\s?(7[0-9]|8[0-9]|9[0-3]),\s?(3[0-9]|4[0-9]|5[0-3])\)'
),
regex.icontains(body.html.raw,
'rgb\((12[0-9]|13[0-9]),\s?(18[0-9]|190),\s?([0-9]|10)\)'
),
regex.icontains(body.html.raw,
'rgb\(([0-9]|1[0-5]),\s?(16[0-5]|166),\s?(23[0-9]|240)\)'
),
regex.icontains(body.html.raw,
'rgb\((25[0-5]),\s?(18[5-9]|19[0-9]),\s?([0-9]|10)\)'
)
)
)
// suspicious content
and (
// current thread is empty, but an image attachment is branded as microsoft.
// common in image as content
(
body.current_thread.text == ""
and any(attachments,
.file_type in $file_types_images
and any(ml.logo_detect(.).brands,
strings.starts_with(.name, "Microsoft")
)
)
)
or (
strings.ilike(body.plain.raw,
"*password*",
"*document*",
"*voicemail*",
"*cache*",
"*fax*",
"*storage*",
"*quota*",
"*message*"
)
and strings.ilike(body.plain.raw,
"*terminated*",
"*review*",
"*expire*",
"*click*",
"*view*",
"*exceed*",
"*clear*",
"*only works*",
"*failed*",
"*deleted*",
"*revalidated*",
"*renewal*"
)
)
or (
any(attachments,
.file_type in $file_types_images
and any(file.explode(.),
strings.ilike(.scan.ocr.raw,
"*password*",
"*document*",
"*voicemail*",
"*cache*",
"*fax*",
"*storage*",
"*quota*",
"*messages*"
)
and strings.ilike(.scan.ocr.raw,
"*terminated*",
"*review*",
"*expire*",
"*click*",
"*view*",
"*exceed*",
"*clear*",
"*only works*",
"*failed*",
"*deleted*"
)
)
)
)
or (
any(file.explode(beta.message_screenshot()),
strings.ilike(.scan.ocr.raw,
"*password*",
"*document*",
"*voicemail*",
"*cache*",
"*fax*",
"*storage*",
"*quota*",
"*messages*"
)
and strings.ilike(.scan.ocr.raw,
"*terminated*",
"*review*",
"*expire*",
"*click*",
"*view*",
"*exceed*",
"*clear*",
"*only works*",
"*failed*",
"*deleted*",
"*revalidated*",
"*renewal*"
)
)
)
or (
any(ml.nlu_classifier(body.current_thread.text).intents,
.name == "cred_theft" and .confidence in~ ("medium", "high")
)
or any(attachments,
.file_type in $file_types_images
and any(file.explode(.),
any(ml.nlu_classifier(.scan.ocr.raw).intents,
.name == "cred_theft"
and .confidence in ("medium", "high")
)
)
)
)
)
and sender.email.domain.root_domain not in (
"bing.com",
"microsoft.com",
"microsoftonline.com",
"microsoftproject.com",
"microsoftstoreemail.com",
"microsoftsupport.com",
"microsoft365.com",
"office.com",
"office365.com",
"onedrive.com",
"sharepointonline.com",
"yammer.com",
)
// negate legitimate Office 365 bouncebacks
and not (
length(attachments) > 0
and all(attachments,
.content_type in ("message/delivery-status", "message/rfc822")
)
and (sender.email.local_part in ('postmaster', 'mailer-daemon'))
)
// negate Microsoft "welcome to the X group" notifications
and not (
headers.auth_summary.dmarc.pass
and length(attachments) == 6
and length(filter(attachments,
strings.istarts_with(.file_name, "GuestWelcomeEmail")
)
) == 5
and length(filter(body.links,
(
.href_url.domain.domain not in (
"outlook.office365.com",
"aka.ms",
"go.microsoft.com"
)
)
and not .href_url.domain.domain == sender.email.domain.domain
)
) == 0
and subject.subject == strings.replace_confusables(subject.subject)
)
// 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().solicited
or (
profile.by_sender().any_messages_malicious_or_spam
and not profile.by_sender().any_false_positives
)
)
and not profile.by_sender().any_false_positives
// exclude marketing jargon from ms partners
and not regex.icontains(body.current_thread.text,
'(schedul(e|ing)|set up).{0,20}(call|meeting|demo|zoom|conversation|time|tool|discussion)|book.{0,10}(meeting|demo|call|slot|time)|connect.{0,12}(with me|phone|email)|my.{0,10}(calendar|cal)|reserve.{0,10}s[pl]ot|break the ice|want to know more?|miss your chance|if you no longer wish|if you no longer want|if you wish to opt out|low-code (development|approach|solution|journey|platform)|(?:invite|virtual).{0,30}(webinar|presentation)'
)
Playground
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