Open Redirect: Club-OS

 1name: "Open Redirect: Club-OS"
 2description: |
 3    Message contains use of the Club-OS open redirect. This has been exploited in the wild.
 4type: "rule"
 5severity: "medium"
 6source: |
 7  type.inbound
 8  and any(body.links,
 9      .href_url.domain.root_domain == "club-os.com"
10      and strings.icontains(.href_url.path, 'click')
11      and strings.icontains(.href_url.query_params, 'target=')
12      // negate hash lookup targets (not actor controlled)
13      and not (
14        regex.icontains(.href_url.query_params, 'target=[a-f0-9]{40}(?:$|&)')
15        and strings.icontains(.href_url.query_params, '&hashLookup=true')
16      )
17      // negate urls that go back to club-os
18      and not regex.icontains(.href_url.query_params, 'target=[^\&]*club-os.com/')   
19  )
20  and (
21    not profile.by_sender().solicited
22    or (
23      profile.by_sender().any_messages_malicious_or_spam
24      and not profile.by_sender().any_false_positives
25    )
26  )
27  
28  // negate highly trusted sender domains unless they fail DMARC authentication
29  and (
30    (
31      sender.email.domain.root_domain in $high_trust_sender_root_domains
32      and not headers.auth_summary.dmarc.pass
33    )
34    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
35  )  
36attack_types:
37  - "Credential Phishing"
38  - "Malware/Ransomware"
39tactics_and_techniques:
40  - "Open redirect"
41detection_methods:
42  - "Sender analysis"
43  - "URL analysis"
44id: "c6286914-059d-5879-8f17-b923304cb628"