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,
19                                  'target=[^\&]*club-os.com/'
20          )
21  )
22  
23  // negate highly trusted sender domains unless they fail DMARC authentication
24  and (
25    (
26      sender.email.domain.root_domain in $high_trust_sender_root_domains
27      and not headers.auth_summary.dmarc.pass
28    )
29    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
30  )  
31attack_types:
32  - "Credential Phishing"
33  - "Malware/Ransomware"
34tactics_and_techniques:
35  - "Open redirect"
36detection_methods:
37  - "Sender analysis"
38  - "URL analysis"
39id: "c6286914-059d-5879-8f17-b923304cb628"