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MS Exchange LDAP Vulnerability

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5 replies

by travisf

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I noticed that our Exhchange server still had LDAP enable for annon. users.

I connected to TCP port 389 with telnet but was unable to do anything with it except to connect. How would someone be able to use this type of connection to gather e.mail addresses? What would you type? ...etc.

I set my terminal to Local Echo, but cannot type any commands. Anyone?

5 replies

by philanderson

are able type anything atall at the command line once connected?
you should try and connect at port23 instead of 389.
remember LDAP is a DIRECTORY SERVICE it is not a true FTP type app.
I use port23 and have no problem type HELP at the command prompt if you can .

by travisf

I understand that LDAP is only a service, but I was just wondering how by leaving that port open to annon. access, would some gain access or get information from my Exchange server? Does that make sense?

by travisf

I understand that LDAP is only a service, but I was just wondering how by leaving that port open to annon. access, would some gain access or get information from my Exchange server? Does that make sense?

by philanderson

if you leave the anonymous LDAP enabled, savvy users can anonymously retrieve the Internet addresses of all of your organization's recipients and use the addresses to send unsolicited commercial e-mail or inappropriate messages.

the most common TCP ports for Exchange
Server are below. For a complete discussion, see Microsoft Support Online
article Q176466
(http://support.microsoft.com/support/kb/articles/Q176/4/66.ASP?LNG=ENG&SA=PER).

- RPC: 135 & 137
- POP3: 110
- IMAP: 143 (Secure IMAP: 993)
- SMTP: 25
- LDAP: 389 (Secure LDAP: 636)
- NNTP: 119

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