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  
21  // negate highly trusted sender domains unless they fail DMARC authentication
22  and (
23    (
24      sender.email.domain.root_domain in $high_trust_sender_root_domains
25      and not headers.auth_summary.dmarc.pass
26    )
27    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
28  )  
29attack_types:
30  - "Credential Phishing"
31  - "Malware/Ransomware"
32tactics_and_techniques:
33  - "Open redirect"
34detection_methods:
35  - "Sender analysis"
36  - "URL analysis"
37id: "c6286914-059d-5879-8f17-b923304cb628"