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Outline

DNS Based Detection of Spam Bots and Host Search Activity

2008

Abstract

We carried out an entropy study on the DNS query traffic from the outside for a university campus network to the top domain DNS server in a university through April 1st, 2007 to July 31st, 2008. The following interesting results are given: (1) The random spam bots have been still alive and/or active in the campus network because we can observe that the unique source IP addresses-based DNS traffic entropy increases as well as the unique DNS query keywords-based one decreases frequently. (2) We have also observed a lot of the reverse name resolution access from the specific site on the campus IP address range. Therefore, it can be concluded that in the campus network, the random spam bots are still active and the campus network is also targeted by the attackers.

References (10)

  1. 1 Entropy Changes in the DNS Query Packets Traffic We performed entropy analysis on the PTR re- source record (RR) based DNS query packets traf- fic (reverse name resolution traffic) from the out- side for the campus network through April 1st, 2007 to July 31st, 2008 (Figure 4).
  2. In Figure 4, we can find interesting peaks of (1) April 3rd, (2) 29th, (3) May 20th, (4) 24th, (5) August 1st, (6) 23rd, (7) 27th, (8) October 9th, (9) 16th, (10) 24th, (11) November 1st, (12) 6th, (13) 26th, (14) December 11th, 2007, (15) January 17th, (16) 19th, (17) 20th, (18) 25th, (19) Febru- ary 14th, (20) 21st, (21) 25th, (22) March 3rd, (23) 12th, (24) 27th, (25) April 17th, (26) 25th, (27) May 4th, 5th, (28) 16th, (29) 20th, (30) 21st, (31) June 3rd, (32) 9th, (33) 22nd, (34) 24th, (35) 25th, (36) July 8th, (37) 9th, (38) 22nd, 2008. And these peaks are categorized into three types, as: {(1), (6), (7), (8), (9), (10), (11), (12), (14), (15), (16), (18), (19), (20), (21), (24), (25), (26), (28), (29), (31), (34), (36), (38)}, {(2), (3), (27)}, References and Notes
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