On Wed, Sep 2, 2020 at 3:17 PM Spike White <spikewhitetx(a)gmail.com> wrote:
What cybersecurity is reporting off of is a particular event number
on its AD controllers. which is showing a connection to a LDAP
port.
Is there another (better) event that it should be looking for
instead? I.e., it should be flagging a simple binding only to an
LDAP port.
Unfortunately, there is not. A DC will log this event:
The following client performed a SASL
(Negotiate/Kerberos/NTLM/Digest) LDAP bind without requesting
signing (integrity verification), or performed a simple bind over
a clear text (non-SSL/TLS-encrypted) LDAP connection.
…for both of these use cases:
1. An LDAP client uses GSSAPI (instead of GSS-SPNEGO), over a signed
and sealed connection. No passwords are transmitted in clear text.
2. An LDAP client performs a simple bind over clear text (without
sealing), which passes the bind password on the wire in clear text.
If the DCs are configured as per Microsoft’s recommendations to secure
LDAP traffic, use case #2 will break. But use case #1 will not.
(Others in the big long thread I referenced in my previous message
verified this.)
At least to my knowledge, no one has figured out a way to sift through
these events in the event log and determine which ones (if any) were
generated by LDAP clients performing simple binds over clear text
(which is undesirable) versus which ones were generated by LDAP
clients using GSSAPI (instead of GSS-SPNEGO) over a sealed connection.
Alas, Microsoft really should have used two different event types to
distinguish these cases.