Actually as I recall, I have heard of this from another colleage few years ago in another company, it turned out a client-pc infected with a virus accessing a sql server..
I found the email.. but no link, so here is a thread of the information.. although it indicates tcp but there may be another using udp.. check in Symantec for any info.
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The CERT/CC is receiving reports of widespread activity related to a
new piece of malicious code known as W32/Blaster. This worm appears to
exploit known vulnerabilities in the Microsoft Remote Procedure Call
(RPC) Interface.
I. Description
The W32/Blaster worm exploits a vulnerability in Microsoft's DCOM RPC
interface as described in VU#568148 and CA-2003-16. Upon successful
execution, the worm attempts to retrieve a copy of the file
msblast.exe from the compromising host. Once this file is retrieved,
the compromised system then runs it and begins scanning for other
vulnerable systems to compromise in the same manner. In the course of
propagation, a TCP session to port 135 is used to execute the attack.
However, access to TCP ports 139 and 445 may also provide attack
vectors and should be considered when applying mitigation strategies.
Microsoft has published information about this vulnerability in
Microsoft Security Bulletin MS03-026.
Lab testing has confirmed that the worm includes the ability to launch
a TCP SYN flood denial-of-service attack against windowsupdate.com. We
are investigating the conditions under which this attack might
manifest itself. Unusual or unexpected traffic to windowsupdate.com
may indicate an infection on your network, so you may wish to monitor
network traffic.
Sites that do not use windowsupdate.com to manage patches may wish to
block outbound traffic to windowsupdate.com. In practice, this may be
difficult to achieve, since windowsupdate.com may not resolve to the
same address every time. Correctly blocking traffic to
windowsupdate.com will require detailed understanding of your network
routing architecture, system management needs, and name resolution
environment. You should not block traffic to windowsupdate.com without
a thorough understanding of your operational needs.
We have been in contact with Microsoft regarding this possibility of
this denial-of-service attack.
II. Impact
A remote attacker could exploit these vulnerabilities to execute
arbitrary code with Local System privileges or to cause a
denial-of-service condition.
Jorge Rodriguez
