Cisco Cisco Email Security Appliance C160 Mode D'Emploi

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User Guide for AsyncOS 9.7 for Cisco Email Security Appliances
 
Chapter 9      Using Message Filters to Enforce Email Policies
  Message Filter Rules
The escaping rules for the 
signed-certificate
 rule’s regular expressions differ from the escaping rules 
defined in LDAP-UTF8 by limiting escaping to only the characters that require escaping. LDAP-UTF8 
allows optional escaping for characters that can be represented without escaping. For example, the 
following two strings are considered correct for “Example, Inc.” using the LDAP-UTF8 escaping rules:
Example\, Inc.
Example\,\ Inc\.
However, the 
signed-certificate 
rule only matches 
Example\, Inc.
 The regular expression does not 
allow escaping the space and period for matching because these characters do not require escaping, even 
though it is permitted in LDAP-UTF8. When creating a regular expression for the 
signed-certificate 
rule, do not escape a character if it can be represented without escaping.
$CertificateSigners Action Variable
The action variable 
$CertificateSigners
 is a comma separated list of signers obtained from the 
subjectAltName
 element of the signing certificate. Multiple email addresses of a single signer will be 
included in the list with duplicates removed.
For example, Alice signs a message with her two certificates. Bob signs the message with his single 
certificate. All certificates are issued by a single corporate authority. After the message passes the 
S/MIME scan, the extracted data contain three items:
The 
$CertificateSigners
 variable expands to:
[
  {
    'issuer': 'CN=Auth,O=Example\, Inc.',
    'signer': ['alice@example.com', 'al@private.example.com']
  },
  {
    'issuer': 'CN=Auth,O=Example\, Inc.',
    'signer': ['alice@example.com', 'al@private.example.com']
  },
  {
    'issuer': 'CN=Auth,O=Example\, Inc.',
    'signer': ['bob@example.com', 'bob@private.example.com']
  }
]
"alice@example.com, al@private.example.com, bob@example.com, bob@private.example.com"