I have hit coming to my site (a large one) that contain strings of zeroes and upper case "Ds" in the user agent strings. They appear to come from varying IP addys and they don't exhibit "crawler behavior" ... in fact, apart from the strangeness in the UA strings they seem to be "real human surfers".

Are these the result of "anonymizer" software of some sort? or something else? (samples with hit counts below for a random day)

ADVthanksANCE for any insights!
=Gneen

Also some listed at:
[botsvsbrowsers.com...]

 230 Mozilla/5.0+(000000000;+0;+00000+000+00+0+000000;+00000)+DDDDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDDDD+DDDDDDDDDDDDDDD 
 154 Mozilla/5.0+(000000000;+0;+00000+000+00+0+0000;+00000;+00000000000)+DDDDDDDDDDDDDDDD+DDDDDDDDDDDDDD 
 132 Mozilla/5.0+(000000000;+0;+00000+000+00+0+000000;+00000)+00000000000000000000+0000000+0000+000000+0000000000000+000000000000000 
 110 Mozilla/5.0+(000000000;+0;+000+000+00+0+0000000;+00)+DDDDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDDDD+DDDDDDDDDDDDDDD 
 72 Mozilla/5.0+(000000000;+0;+000+000+00+0+0000;+00000;+00000000000)+DDDDDDDDDDDDDDDD+DDDDDDDDDDDDDD 
 68 Mozilla/5.0+(000000000;+0;+00000+000+00+0+000000;+00000)+DDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDD+DDDDDDDDDDDDD 
 58 Mozilla/5.0+(000000000;+0;+00000+000+00+0+000000;+00000)+DDDDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDD+DDDDDDDDDDDDD 
 22 Mozilla/5.0+(000000000;+0;+00000+000+00+0+0000000;+00)+DDDDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDDDD+DDDDDDDDDDDDDDD 
 18 Mozilla/5.0+(000000000;+0;+00000+000+00+0+0000;+00000;+0000000000)+DDDDDDDDDDDDDDDD+DDDDDDDDDDDDD 
 18 Mozilla/5.0+(000000000;+0;+000+000+00+0+0000000;+00)+00000000000000000000+0000000+0000+000000+0000000000000+000000000000000 
 12 Mozilla/5.0+(000000000;+0;+00000+000+00+0;+00000)+DDDDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDDDD+DDDDDDDDDDDDD 
 10 Mozilla/5.0+(000000000;+0;+000+000+00+0+000000;+00000)+DDDDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDDDD+DDDDDDDDDDDDDDD 
 6 Mozilla/5.0+(000000000;+0;+00000+000+00+0+000000;+00000)+000000000000000000+0000000+0000+000000+00000000000+0000000000000 
 3 Mozilla/5.0+(000000000;+0;+000+000+00+0+0000;+00000;+00000000000)+0000000000000000+00000000000000 
 2 Mozilla/5.0+(000000000;+0;+00000+000+00+0+0000;+00000;+00000000000)+0000000000000000+00000000000000 
 2 Mozilla/5.0+(000000000;+0;+00000+000+00+0+0000000;+00)+00000000000000000000+0000000+0000+000000+0000000000000+000000000000000 
 2 Mozilla/5.0+(000000000;+0;+000+000+00+0+000000;+00000;+00000000000)+00000000000000+0000000000000000 
 2 Mozilla/5.0+(000000000;+0;+000+000+00+0+000000;+00000)+DDDDDDDDDDDDDDDDDD+DDDDDDD+DDDD+DDDDDD+DDDDDDDDDDD+DDDDDDDDDDDDD 
 2 Mozilla/5.0+(000000000;+0;+000+000+00+0+0000000;+00)+00000000000000000000+0000000+0000+000000+0000000000000+0000000005.27.1