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R__Clark_149098's avatar
R__Clark_149098
Icon for Altocumulus rankAltocumulus
Jan 23, 2019

LDAP Query for Attribute

I apologize if this has been covered in a different article, but I have not been able to find anything that I've had success with. In my environment, a user's DistinguishedName is totally unique, ...
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security
  • R__Clark_149098's avatar
    R__Clark_149098
    Feb 05, 2019

    I ultimately got this working by creating an LDAP Query action, I used the following as a SearchFilter:

    (SamAccountName=%{session.logon.last.username})

    I set DistinguishedName as a required attribute so that I was able to use it later. These are case sensitive when you try to use them in Variable Assigns, so make sure to check the session variables after a login attempt if things aren't working.

    The format of my LDAP users DN is CN=Bob\, Smith... or CN=Bob... so I had to cover both cases. The F5 adds an extra slash to the session variable to make it a literal slash in TCL (my guess). I had to create a variable assign to remove that extra slash so when it's sent to the LDAP server it understands it.

    This was the expression field of my variable assign:

    set dn "[mcget {session.ldap.last.attr.dn}]"
if {[string first "\\" $dn] != -1} {
    return [string map {\\\\ \\} $dn]
} else {
    return $dn
}

    Finally I created an LDAP auth action with the following in the UserDN. SearchDN and SearchFilter are empty.

    I had to open a case with F5 to figure out how to not send hex to my LDAP server. They key is the :noconv function. 

    %{dn:noconv}

    After this authentication worked!!

Niels_van_Sluis's avatar
Niels_van_Sluis
Icon for MVP rankMVP
Jan 24, 2019

I've used searchfilters like this:

(|(sAMAccountName=%{session.logon.last.username})(userPrincipalName=%{session.logon.last.username}))

Try ldapsearch from the command line to first check if the query is working:

ldapsearch -x -LLL -h 10.10.10.10 -D 'Administrator@example.com' -w S3cr3tP@ss -b 'dc=example,dc=com' -s sub "(|(sAMAccountName=bob@example.com)(userPrincipalName=bob.smith@example.com))" sAMAccountName

And try using the SearchDN: 

dc=example,dc=com