Security
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Splunk LDAP authentication, wrong filter?

Engager

Hey there,

I have been trying to figure out why Splunk can't authenticate against my OpenLDAP server. Current configuration looks like this:


SSLEnabled = 1
anonymousreferrals = 0
bindDN = cn=admin,ou=meta,dc=my,dc=example,dc=com
bindDNpassword =
charset = utf8
groupBaseDN = ou=Group,dc=my,dc=example,dc=com
groupBaseFilter = (|(cn=GROUP1)(cn=GROUP2))
groupMappingAttribute = dn
groupMemberAttribute = memberuid
groupNameAttribute = cn
host = my.example.com
nestedGroups = 0
network
timeout = -1
port = 636
realNameAttribute = cn
sizelimit = 10000
timelimit = 29
userBaseDN = ou=People,dc=my,dc=example,dc=com
userBaseFilter = (objectClass=posixAccount)
userNameAttribute = uid

Groups are mapped correctly (GROUP1 and GROUP2), but the users within these groups cannot authenticate. I have been looking at the LDAP logs and I can see these filters:

This specific ones, successfully gets the user data.

conn=379662 op=1 SRCH base="ou=People,dc=my,dc=example,dc=com" scope=2 deref=0 filter="(&(uid=USERNAME)(objectClass=posixAccount)(cn=*))"

Now this one is generated to look for the groups that this specific user is a member of:

conn=379662 op=2 SRCH base="ou=Group,dc=my,dc=example,dc=com" scope=2 deref=0 filter="(&(memberUid=uid=USERNAME,ou=people,dc=my,dc=example,dc=com)(|(cn=GROUP1)(cn=GROUP2))(cn=*))"

But it returns nothing, so user is not logged in, so essentially the filter does not work.

However this filter works:

(&(memberUid=lkamenov)(|(cn=GROUP1)(cn=GROUP2))(cn=*))

Anyone have an idea what could be going wrong exactly? Would appreciate any help!

Thank you
Lou

Tags (2)
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Re: Splunk LDAP authentication, wrong filter?

SplunkTrust
SplunkTrust

Within your group definitions, does memberUid refer to a WHOLE DN, or just the 'short name'?

Your examples suggest that the members of groups are referred to by just the uid=lkamenov attribute and not the entire uid=lkamenov,ou=people,dc=my,dc=example,dc=com.

Based on your examples, I would suggest setting

groupMappingAttribute = uid

In your authentication.conf. This (should) make Splunk use the "simple" uid attribute instead of the whole DN for purposes of group matching.

Note, however, that this makes group memebership ambiguous when the same uid exists in multiple OU's. ( Meaning uid=lkamenov,ou=people,dc=my,dc=domain,dc=com and uid=lkamenov,ou=otherpeople,dc=my,dc=domain,dc=com would both match the group membership attribute of uid=lkamenov)

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Re: Splunk LDAP authentication, wrong filter?

SplunkTrust
SplunkTrust

Did this solve your issue? An update would be appreciated.

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Re: Splunk LDAP authentication, wrong filter?

Engager

I used the full DN and that worked nicely. Thanks for the help!

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