Core. Files ? Part Of Full Page Caching Or ?

Just curious, checked my root folder of the webstore and found a few core.** files.

I opened them in Sublime Text Editor and all it shows are hexadecimals

00d0 7a15 0000 0000 0060 1b12 db7f 0000
0000 0000 0000 0000 0010 0000 0000 0000
00c0 0100 0000 0000 0010 0000 0000 0000
0100 0000 0000 0000 00e0 7a15 0000 0000
0020 1d12 db7f 0000 0000 0000 0000 0000
0000 0000 0000 0000 00f0 1f00 0000 0000
0010 0000 0000 0000 0100 0000 0600 0000
00e0 7a15 0000 0000 0010 3d12 db7f 0000
0000 0000 0000 0000 0060 0000 0000 0000
0060 0000 0000 0000 0010 0000 0000 0000
0100 0000 0500 0000 0040 7b15 0000 0000
0070 3d12 db7f 0000 0000 0000 0000 0000
0010 0000 0000 0000 00a0 0000 0000 0000
0010 0000 0000 0000 0100 0000 0000 0000
0050 7b15 0000 0000 0010 3e12 db7f 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 2000 0000 0000 0010 0000 0000 0000
0100 0000 0600 0000 0050 7b15 0000 0000
0010 5e12 db7f 0000 0000 0000 0000 0000
0020 0000 0000 0000 0020 0000 0000 0000
0010 0000 0000 0000 0100 0000 0500 0000
0070 7b15 0000 0000 0030 5e12 db7f 0000
0000 0000 0000 0000 0010 0000 0000 0000

You may want to post file names as well.

Just curious, checked my root folder of the webstore and found a few core.** files.

I opened them in Sublime Text Editor and all it shows are hexadecimals

00d0 7a15 0000 0000 0060 1b12 db7f 0000
0000 0000 0000 0000 0010 0000 0000 0000
00c0 0100 0000 0000 0010 0000 0000 0000
0100 0000 0000 0000 00e0 7a15 0000 0000
0020 1d12 db7f 0000 0000 0000 0000 0000
0000 0000 0000 0000 00f0 1f00 0000 0000
0010 0000 0000 0000 0100 0000 0600 0000
00e0 7a15 0000 0000 0010 3d12 db7f 0000
0000 0000 0000 0000 0060 0000 0000 0000
0060 0000 0000 0000 0010 0000 0000 0000
0100 0000 0500 0000 0040 7b15 0000 0000
0070 3d12 db7f 0000 0000 0000 0000 0000
0010 0000 0000 0000 00a0 0000 0000 0000
0010 0000 0000 0000 0100 0000 0000 0000
0050 7b15 0000 0000 0010 3e12 db7f 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 2000 0000 0000 0010 0000 0000 0000
0100 0000 0600 0000 0050 7b15 0000 0000
0010 5e12 db7f 0000 0000 0000 0000 0000
0020 0000 0000 0000 0020 0000 0000 0000
0010 0000 0000 0000 0100 0000 0500 0000
0070 7b15 0000 0000 0030 5e12 db7f 0000
0000 0000 0000 0000 0010 0000 0000 0000

I has the same structure as a bitmap file, yet I would have no idea what it is D:. Maybe schemas for structure files? Or PHP encoded files?

You may want to post file names as well.

I downloaded them all and removed them from the root but it is core.

Have not seen them since I last purged xVarnish.

UPDATE

those corefiles are dumpfiles from the server put out by xVarnish. Nothing serious like hack attempt as I mistakenly thought they were.