lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Date: Tue, 25 Feb 2014 17:21:39 -0400
From: Pedro Luis Karrasquillo <peter_toyota@...mail.com>
To: "full-disclosure@...ts.grok.org.uk" <full-disclosure@...ts.grok.org.uk>
Subject: Microsoft DNS server unwitting DDoS contributor

...not sure how the first message got included in the freepbx thread, so I am trying again:

Microsoft has responded to my report to secure@...rosoft.com and I can now disclose what I found. Microsoft determined this is all by design, so no changes to the server functionality is planned.

There is a minor bug on the MS Server 2008 DNS service that responds with the list of all root servers when queried for non-authoritative domains, EVEN when recursion is set to OFF. This allows a malicious party to spoof the source ip on a udp DNS request to any MS Server 2008 DNS and elicit a 533 byte response to a victim, making the server a contributor to coordinated Distributed Denial of Service attacks. The response contains the default list of root DNS servers.
Version tested: MS DNS on MS Server 2008 R2 version 6.1.7601.17514

Server is Authoritative to only one .com domain.

Config Parameters:

    DNS Recursion set to "disable"
    Enable Round Robin
    Enable Netmask Ordering
    Secure Cache against pollution 

And My Mitigation steps:

    Remove all root DNS servers listed on the "Root Hints" tab. 

This will not negatively affect the DNS functionality of the server when deployed only as an authoritative server for a specific domain.


Although RFC1034 on page 21 does allow the DNS to reply with the list of root servers (if configured) as a response option, ultimately it is preferable for it to mimic the behavior of BIND and not respond at all under these test conditions, to discourage abuse from malicious entities.


More details with images and packet captures and the Microsoft responses, in my web file http://pe.l├║ka.com/


Pedro
CCNP, CCDA, CCNA-Security, SANS GPEN
...But mostly a curious guy.
 		 	   		  
Content of type "text/html" skipped

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

Powered by blists - more mailing lists