Craig contacted the Storm Center inquiring about an interesting scan he has seen on his server for the last several days.  The scan is at the same time everyday and only runs for a brief time, but it comes from random IPs and at a volume which almost cripples his web server for the duration of the scan.

Below are some sample logs:

209.19.138.103 - - [13/Aug/2012:06:12:53 -0500] "GET /usmle-step-2-ck%26sa%3DU%26ei%3DweAoUKXcGO7ciQLpqoHACQ%26ved%3D0CCAQFjAE%26usg%3DAFQjCNGLZeLateC1dfcmOI4HHHZ33eaFbQ HTTP/1.1" 404 27320
207.70.9.103 - - [13/Aug/2012:06:12:53 -0500] "GET /usmle-step-1/step1%26sa%3DU%26ei%3DweAoUKXcGO7ciQLpqoHACQ%26ved%3D0CDIQFjAN%26usg%3DAFQjCNE7gGV1WVr1oas2WycwK6HXMTDc9Q HTTP/1.1" 404 27323
209.19.152.71 - - [13/Aug/2012:06:12:55 -0500] "GET /comlex-level-1%26sa%3DU%26ei%3DweAoUKXcGO7ciQLpqoHACQ%26ved%3D0CCQQFjAG%26usg%3DAFQjCNE9KmW1x2RLSZwTtSFJQlaciBdtZQ HTTP/1.1" 404 27319
209.19.182.245 - - [13/Aug/2012:06:12:53 -0500] "GET /pharmacology/%26sa%3DU%26ei%3DweAoUKXcGO7ciQLpqoHACQ%26ved%3D0CBoQFjAB%26usg%3DAFQjCNGWpETjIQO-QezV9OEnvmPeKrlWDA HTTP/1.1" 404 27318
207.70.60.19 - - [13/Aug/2012:06:12:53 -0500] "GET /usmle-step-2-ck/coupons/2g35%26sa%3DU%26ei%3DweAoUKXcGO7ciQLpqoHACQ%26ved%3D0CDAQFjAM%26usg%3DAFQjCNEgHYVBqXDBUNuyVgwAjaAlyRl12A HTTP/1.1" 404 27333

They all appear to be a potentially valid URL followed by an encoded string and all the requests appear to be looking for content related to US medical certification exams. 

I haven't been able to find any further information on this scan.  If any of you has seen this, or can provide any insight we would appreciate a heads up, either through our comments section or our contact page.  I will summarize any information that comes in.

Update: Craig's site is a USMLE testing prep company.  The URLs are valid for his site, it is the encoded bit after the URL that is of interest.

-- Rick Wanner - rwanner at isc dot sans dot org - http://namedeplume.blogspot.com/ - Twitter:namedeplume (Protected)