Fake email quarantine notification
Detects phishing messages implying that emails have been delayed or blocked, prompting users to view, release, or delete pending messages.
Sublime rule (View on GitHub)
1name: "Fake email quarantine notification"
2description: "Detects phishing messages implying that emails have been delayed or blocked, prompting users to view, release, or delete pending messages."
3type: "rule"
4severity: "high"
5source: |
6 type.inbound
7
8 and length(body.links) < 10
9 and (
10 any(ml.nlu_classifier(body.current_thread.text).intents,
11 .name == "cred_theft" and .confidence == "high"
12 )
13 or (
14 length(body.current_thread.text) < 250
15 and any(recipients.to,
16 strings.icontains(body.current_thread.text, .email.domain.sld)
17 or strings.icontains(body.current_thread.text, .email.local_part)
18 )
19 )
20 )
21 and (
22 3 of (
23 strings.ilike(body.current_thread.text, "*review*"),
24 strings.ilike(body.current_thread.text, "*release*"),
25 strings.ilike(body.current_thread.text, "*quaratine*"),
26 strings.ilike(body.current_thread.text, "*messages*"),
27 strings.ilike(body.current_thread.text, "*blocked*"),
28 strings.ilike(body.current_thread.text, "*notification*"),
29 strings.ilike(body.current_thread.text, "*kindly*"),
30 strings.ilike(body.current_thread.text, "*on hold*"),
31 strings.ilike(body.current_thread.text, "*pending*")
32 )
33 )
34 and (
35 any(body.links,
36 regex.icontains(.display_text, "view", "release", "messages", "delete")
37 )
38 or (
39 length(body.links) < 3
40 and any(body.links,
41 any(recipients.to,
42 .email.domain.root_domain == ..display_url.domain.root_domain
43 and ..mismatched
44 )
45 )
46 )
47 )
48 and not any(body.links,
49 regex.icontains(.display_text,
50 "view document",
51 "review (&|and) sign document"
52 )
53 )
54 and sender.email.domain.root_domain not in (
55 "bing.com",
56 "microsoft.com",
57 "microsoftonline.com",
58 "microsoftsupport.com",
59 "microsoft365.com",
60 "office.com",
61 "office365.com",
62 "onedrive.com",
63 "sharepointonline.com",
64 "yammer.com",
65 "ppops.net"
66 )
67
68 // negate org domains unless they fail DMARC authentication
69 and (
70 (
71 sender.email.domain.root_domain in $org_domains
72 and not headers.auth_summary.dmarc.pass
73 )
74 or sender.email.domain.root_domain not in $org_domains
75 )
76
77 // negate highly trusted sender domains unless they fail DMARC authentication
78 and (
79 (
80 sender.email.domain.root_domain in $high_trust_sender_root_domains
81 and not headers.auth_summary.dmarc.pass
82 )
83 or sender.email.domain.root_domain not in $high_trust_sender_root_domains
84 )
85 and not profile.by_sender().solicited
86 and not profile.by_sender().any_false_positives
87
88attack_types:
89 - "Credential Phishing"
90tactics_and_techniques:
91 - "Social engineering"
92detection_methods:
93 - "Content analysis"
94 - "Natural Language Understanding"
95 - "Sender analysis"
96id: "73f26a3d-b7a5-5b85-83e6-45f1b40f78fb"