Need help!--TFTP Filename Buffer Overflow

[banlanc]

Hi All,

Would you please help me on these messages? Cause I keep getting those every day, I am wondering there is something happen, but I am not sure how. The source ip is our DNS server and destination ip from outside.

IN,OUT,3,4613,0,TCP/IP,source ip,destination ip,53,69,0.0.0.0,GET/PUT filename

IN,OUT,3,4613,0,TCP/IP,source ip,destination ip,53,69,0.0.0.0,GET/PUT filename

IN,OUT,3,4613,0,TCP/IP,source ip,destination ip,53,69,0.0.0.0,GET/PUT filename

IN,OUT,3,4613,0,TCP/IP,source ip,destination ip,53,69,0.0.0.0,GET/PUT filename

IN,OUT,3,4613,0,TCP/IP,source ip,destination ip,53,69,0.0.0.0,GET/PUT filename

IN,OUT,3,4613,0,TCP/IP,source ip,destination ip,53,69,0.0.0.0,GET/PUT filename

Thanks in advance.

Banlan

[mcerha]

This is a false positive. The DNS server is responding to a client that is using port 69 (the TFTP port). Because the traffic is UDP, the sensor is confusing the DNS traffic as TFTP activity. Something the DNS response matchs the regex for this signatures. Applying a filter for this alarm with the DNS server as a source will eliminate this problem.

[darin.marais]

I posted a similar occurance some time back. You may want to have a look at the thread. however I think cisco has already answered your question.

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.ee9fd64/0#selected_message