SSL Certificates with Punycode
The following analytic detects SSL certificates with Punycode domains in the SSL issuer email domain, identified by the prefix "xn--". It leverages the Certificates Datamodel to flag these domains and uses CyberChef…
Description
The following analytic detects SSL certificates with Punycode domains in the SSL issuer email domain, identified by the prefix "xn--". It leverages the Certificates Datamodel to flag these domains and uses CyberChef for decoding. This activity is significant as Punycode can be used for domain spoofing and phishing attacks. If confirmed malicious, attackers could deceive users and systems, potentially leading to unauthorized access and data breaches.
Detection logic
Detection requirements
- Platform
- ESXiLinuxmacOSNetwork DevicesWindows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
Known benign triggers
- False positives may be present if the organization works with international businesses. Filter as needed.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| community.emergingthreats.net/t/out-of-band-ruleset-update-summary-2022-11-01/117 | 2 |
| github.com/corelight/CVE-2022-3602/tree/master/scripts | 2 |
| www.openssl.org/blog/blog/2022/11/01/email-address-overflows/ | 2 |
| www.splunk.com/en_us/blog/security/nothing-puny-about-cve-2022-3602.html | 2 |
From the source
- At source
- Open at source
- Upstream identifier
- 696694df-5706-495a-81f2-79501fa11b90
- Tagged by the source as
- OpenSSL CVE-2022-3602NetworknetworkSplunk CloudSplunk EnterpriseSplunk Enterprise Securitynetwork
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1