Detection rules › Sublime MQL
Link: QuickBooks image lure with suspicious link
This rule detects messages with image attachments containing QuickBooks logo containing exactly 1 link to a suspicious URL.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Credential Phishing |
| Tactics and techniques | Impersonation: Brand, Social engineering |
Event coverage
Rule body MQL
type.inbound
and length(attachments) < 3
and any(attachments,
.file_type in $file_types_images
and any(ml.logo_detect(.).brands, .name == "Quickbooks")
)
and length(body.links) == 1
and (
// body text is very short
(
0 <= (length(body.current_thread.text)) < 10
or body.current_thread.text is null
)
or (
length(body.current_thread.text) < 1500
// or body is most likely all warning banner (text contains the sender and common warning banner language)
and (
regex.icontains(body.current_thread.text,
'caution|confidentiality notice|warning|disclaimer|permission'
)
)
)
)
// 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 .href_url.domain.domain in $social_landing_hosts
or
// mass mailer link, masks the actual URL
.href_url.domain.root_domain in (
"hubspotlinks.com",
"mandrillapp.com",
"sendgrid.net",
"naylorcampaigns.com",
"rs6.net"
)
)
// 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",
"intuit.com",
"turbotax.com",
"intuit.ca"
)
or any(body.links, .href_url.domain.domain in $free_file_hosts)
)
and .href_url.domain.root_domain not in $org_domains
)
and sender.email.domain.root_domain not in~ (
'intuit.com',
'turbotax.com',
'intuit.ca'
)
// 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
)
Detection logic
Scope: inbound message.
This rule detects messages with image attachments containing QuickBooks logo containing exactly 1 link to a suspicious URL.
- inbound message
- length(attachments) < 3
any of
attachmentswhere all hold:- .file_type in $file_types_images
any of
ml.logo_detect(.).brandswhere:- .name is 'Quickbooks'
- length(body.links) is 1
any of:
any of:
all of:
- length(body.current_thread.text) ≥ 0
- length(body.current_thread.text) < 10
- body.current_thread.text is missing
all of:
- length(body.current_thread.text) < 1500
- body.current_thread.text matches 'caution|confidentiality notice|warning|disclaimer|permission'
any of
body.linkswhere all hold:any of:
- .href_url.domain.root_domain not in $tranco_1m
- .href_url.domain.domain in $free_file_hosts
- .href_url.domain.root_domain in $free_file_hosts
- .href_url.domain.root_domain in $free_subdomain_hosts
- .href_url.domain.domain in $url_shorteners
- .href_url.domain.domain in $social_landing_hosts
- .href_url.domain.root_domain in ('hubspotlinks.com', 'mandrillapp.com', 'sendgrid.net', 'naylorcampaigns.com', 'rs6.net')
any of:
- .href_url.domain.root_domain not in ('svc.ms', 'sharepoint.com', '1drv.ms', 'microsoft.com', 'aka.ms', 'msftauthimages.net', 'intuit.com', 'turbotax.com', 'intuit.ca')
any of
body.linkswhere:- .href_url.domain.domain in $free_file_hosts
- .href_url.domain.root_domain not in $org_domains
- sender.email.domain.root_domain not in ('intuit.com', 'turbotax.com', 'intuit.ca')
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
Inspects: attachments[].file_type, body.current_thread.text, body.links, body.links[].href_url.domain.domain, body.links[].href_url.domain.root_domain, headers.auth_summary.dmarc.pass, sender.email.domain.root_domain, type.inbound. Sensors: ml.logo_detect, regex.icontains. Reference lists: $file_types_images, $free_file_hosts, $free_subdomain_hosts, $high_trust_sender_root_domains, $org_domains, $social_landing_hosts, $tranco_1m, $url_shorteners.
Indicators matched (19)
| Field | Match | Value |
|---|---|---|
ml.logo_detect(attachments[]).brands[].name | equals | Quickbooks |
regex.icontains | regex | caution|confidentiality notice|warning|disclaimer|permission |
body.links[].href_url.domain.root_domain | member | hubspotlinks.com |
body.links[].href_url.domain.root_domain | member | mandrillapp.com |
body.links[].href_url.domain.root_domain | member | sendgrid.net |
body.links[].href_url.domain.root_domain | member | naylorcampaigns.com |
body.links[].href_url.domain.root_domain | member | rs6.net |
body.links[].href_url.domain.root_domain | member | svc.ms |
body.links[].href_url.domain.root_domain | member | sharepoint.com |
body.links[].href_url.domain.root_domain | member | 1drv.ms |
body.links[].href_url.domain.root_domain | member | microsoft.com |
body.links[].href_url.domain.root_domain | member | aka.ms |
7 more
body.links[].href_url.domain.root_domain | member | msftauthimages.net |
body.links[].href_url.domain.root_domain | member | intuit.com |
body.links[].href_url.domain.root_domain | member | turbotax.com |
body.links[].href_url.domain.root_domain | member | intuit.ca |
sender.email.domain.root_domain | member | intuit.com |
sender.email.domain.root_domain | member | turbotax.com |
sender.email.domain.root_domain | member | intuit.ca |