""ET POLICY Outbound SMTP NTLM Authentication Observed""

SID: 2027152

Revision: 2

Class Type: policy-violation

Metadata: attack_target Client_and_Server, created_at 2019_04_04, deployment Perimeter, performance_impact Low, signature_severity Minor, updated_at 2019_04_04

Reference:

Protocol: tcp

Source Network: $HOME_NET

Source Port: any

Destination Network: $EXTERNAL_NET

Destination Port: [25,587]

Flow: established,to_server

Contents:

  • Value: "AUTH|20|ntlm|20|" Depth: 10

Within:

PCRE: "/^(?:[A-Z0-9+/]{4})*(?:[A-Z0-9+/]{2}==|[A-Z0-9+/]{3}=|[A-Z0-9+/]{4})$/Ri"

Special Options:

  • nocase

  • fast_pattern

source