Protocols passing authentication in cleartext
The following analytic identifies the use of cleartext protocols that risk leaking sensitive information. It detects network traffic on legacy protocols such as Telnet (port 23), POP3 (port 110), IMAP (port 143), and…
Description
The following analytic identifies the use of cleartext protocols that risk leaking sensitive information. It detects network traffic on legacy protocols such as Telnet (port 23), POP3 (port 110), IMAP (port 143), and non-anonymous FTP (port 21). The detection leverages the Network_Traffic data model to identify TCP traffic on these ports. Monitoring this activity is crucial as it can expose credentials and other sensitive data to interception. If confirmed malicious, attackers could capture authentication details, leading to unauthorized access and potential data breaches.
Detection logic
Detection requirements
- Log source category
- cisco_secure_firewall_threat_defense_connection_event
Known benign triggers
- Some networks may use leverage clear text protocols such as kerberos, FTP or telnet servers. Apply the necessary exclusions where needed.
MITRE ATT&CK mappings
Not mapped to ATT&CK.
References
| Reference | Cited by |
|---|---|
| www.infosecmatter.com/capture-passwords-using-wireshark/ | Only this detection cites it |
| www.rackaid.com/blog/secure-your-email-and-file-transfers/ | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 6923cd64-17a0-453c-b945-81ac2d8c6db9
- Tagged by the source as
- Cisco Secure Firewall Threat Defense AnalyticsScattered Lapsus$ HuntersUse of Cleartext ProtocolsEndpointnetworkSplunk 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