SMTP on Port 26/TCP
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About the rule
Rule Type
Standard
Rule Description
This rule detects events that may indicate use of SMTP on TCP port 26. This port is commonly used by several popular mail transfer agents to deconflict with the default SMTP port 25. This port has also been used by a malware family called BadPatch for command and control of Windows systems.
Severity
Trouble
Rule Requirement
Criteria
Action1: actionname = "DETECTION_ACTION_NETWORK_NETWORK_TRAFFIC" AND (PROTOCOL_TR = "tcp" AND DEST_PORT = 26) AND (APPLICATION = "smtp" OR COMPONENT = "smtp" OR EVENT_TYPE = "smtp") select Action1.HOSTNAME,Action1.SOURCE_IP,Action1.SOURCE_PORT,Action1.SOURCE_MAC,Action1.SOURCE_INTERFACE,Action1.DEST_NAME,Action1.DESTINATIONHOST,Action1.DEST_IP,Action1.DEST_PORT,Action1.DEST_MAC,Action1.DEST_INTERFACE,Action1.PROTOCOL_APP,Action1.PROTOCOL_TR,Action1.DIRECTION,Action1.DIRECTION_TR,Action1.FW_DIRECTION,Action1.URL_SITE,Action1.URL_ARG,Action1.APPLICATION,Action1.MESSAGE
Detection
Execution Mode
realtime
Log Sources
Network
