Brand impersonation: Punchbowl

 1name: "Brand impersonation: Punchbowl"
 2description: "Detects messages impersonating Punchbowl invitations not originating from legitimate Punchbowl domain."
 3type: "rule"
 4severity: "medium"
 5source: |
 6  type.inbound
 7  // Looking for Punchbowl phrasing in all body threads
 8  and (
 9    strings.icontains(body.current_thread.text, "punchbowl")
10    // Look for alt text in HTML for standardized Punchbowl formatting if string is not avail.
11    or strings.icontains(body.html.raw, 'alt="Punchbowl"')
12    // image sourced from punchbowl
13    or any(html.xpath(body.html, '//img/@src').nodes,
14           strings.parse_url(.raw).domain.domain == "static.punchbowl.com"
15           and strings.icontains(strings.parse_url(.raw).path, '/invitation')
16    )
17  )
18  // Phrasing is typically "You're invited"
19  and (
20    strings.icontains(body.current_thread.text, "you're invited")
21    //
22    // This rule makes use of a beta feature and is subject to change without notice
23    // using the beta feature in custom rules is not suggested until it has been formally released
24    //
25    or (
26      strings.icontains(beta.ocr(file.message_screenshot()).text,
27                        "you're invited",
28                        "open me",
29                        "manage invitation"
30      )
31      and regex.icontains(body.current_thread.text, 'don.t want .{1,40}\?')
32    )
33    or any([
34             html.xpath(body.html,
35                        '//a//img[contains(@src, "btn_open_invitation")]'
36             ).nodes,
37             html.xpath(body.html,
38                        '//a//img[contains(@src, "btn_open_save_the_date")]'
39             ).nodes,
40           ],
41           any(.,
42               regex.icontains(.inner_text,
43                               '(?:open|save).{0,10}(?:invitation|the date)'
44               )
45           )
46    )
47  )
48  // Legitimate sender will be from punchbowl, negating known non-associated domains.
49  and not sender.email.domain.root_domain in ("punchbowl.com", "punchbowl.news")
50  // Capping length to limit FP's
51  and length(body.current_thread.text) < 1500  
52attack_types:
53  - "Credential Phishing"
54tactics_and_techniques:
55  - "Impersonation: Brand"
56  - "Social engineering"
57detection_methods:
58  - "Content analysis"
59  - "Sender analysis"
60id: "58937ba0-6966-559a-bd4f-759ee8b2979e"