I assume these are some sort of bots, but would like to know what are they trying to do to my server.
The logs in questions are below and the IP address has been changed from the original.
12.34.56.78 - - [18/Oct/2012:16:48:20 +0100] "\x86L\xED\x0C\xB0\x01|\x80Z\xBF\x7F\xBE\xBE" 400 172 "-" "-"
12.34.56.78 - - [18/Oct/2012:16:50:28 +0100] "\x84K\x1D#Z\x99\xA0\xFA0\xDC\xC8_\xF3\xAB1\xE2\x86%4xZ\x04\xA3)\xBCN\x92r*\xAAN\x5CF\x94S\xE3\xAF\x96r]j\xAA\xC1Y_\xAE\xF0p\xE5\xBAQiz\x14\x9F\x92\x0C\xCC\x8Ed\x17N\x08\x05" 400 172 "-" "-"
12.34.56.78 - - [18/Oct/2012:16:58:32 +0100] "g\x82-\x9A\xB8\xF0\xFA\xF4\xAD8\xBA\x8FP\xAD\x0B0\xD3\xB2\xD2\x1D\xFF=\xAB\xDEC\xD5\xCB\x0B*Z^\x187\x9C\xB6\xA6V\xB8-D_\xFE" 400 172 "-" "-"
12.34.56.78 - - [18/Oct/2012:17:06:59 +0100] "\xA61[\xB5\x02*\xCA\xB6\xC6\xDB\x92#o.\xF4Kj'H\xFD>\x0E\x15\x0E\x90\xDF\xD0R>'\xB8A\xAF\xA3\x13\xB3c\xACI\xA0\xAA\xA7\x9C\xCE\xA3\x92\x85\xDA\xAD1\x08\x07\xFC\xBB\x0B\x95\xA8Z\xCA\xA1\xE0\x88\xAEP" 400 172 "-" "-"
12.34.56.78 - - [18/Oct/2012:17:13:53 +0100] "b\xC4\xA24Z\xA2\x95\xEFc\xAF\xF1\x93\xE8\x81\xFD\xB4\xDEo\x92\xC0v\x1Fe\xD8W\x85\xC7O\x9D\x8C\x89<" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:09:56:39 +0100] "\x93d\xD8\x85\xD3f\x182\x94\x10\xE6y\x06\x7F\xE5\x97\xA8S\x8AfZ\x84\x0C\x0F\xFD\x19d*+\x09%\xEC3EG\xDD:Tn\xDA" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:10:07:10 +0100] ">\x92\xD7\x85\xC2\x5C\xDA\x8CJX\xBE\x87\x01\xBA\x09\xADj\xEDT.\x02z\x0B\xCA\x00\xAC\xDC[_;q\xC15\x17\xE9\x0B\x9F\xDA;\xEC\xDA)\xB8\x91\xA2\xB5P\xE9\x81\xF2\xD5\xD3\xC4\xD3" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:10:09:53 +0100] "\x12\x9E>\xFC\xF4\x07,\x9A\xF5G\xB4\xD0\xD4\xF1\xCB9\x9FRl\xB0\xDB\x84a\x90\x7F{\xB1\xA3\xD9-5\xF8\x94~\xCEm\x87\xEC\xB4\xE2s\xBD\xDB@" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:10:24:49 +0100] "\x98\xCA\xD3\x95|&t\x1Cp\x02\xF7\x88m\x08T\xE7tm\x9E\x04\xFB\x85\xB7\x08\xB3\xA0-Z\x03\xD5O\x98\xC6\x0EK|\xA1" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:10:27:58 +0100] "\x11\xE8.^\x0E\x8B}\x81\xAD\xA3^\x9E\xDFg2?@\xCB\x1Ej\xC7h\xB00\xF0\xDC\x92\x9B@\xFD\xBChB\xBF7tF\x17+W\xFFV\x8F" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:10:40:43 +0100] "Ou\xB3\x89\x8DiB\x82\x9D\xE8?wshxLF'\x0F\xB2o\xF6\xCD\xFC\xC2\x82ck\xC4\xF7\x0F\x01\xBC\x8B\xDA\x93|\xEAL\x81\xED`Rbr\x0F\xC1\xC8T\xDE\x07\x91\xF5|J\x5C\xBD70\x22\xD5\xA5p\xF4\xF4\xAA\xC2\xF2a\x19\xFE" 400 172 "-" "-"
12.34.56.78 - - [19/Oct/2012:10:41:29 +0100] "[8]\xCC\x7F\x1E\xA9\xE6f\xD7<\xA9\x18\xD9\xC0\xD0j~O\x90C\x8D]hVz\x84\x94y]\x95{.\x13m_];W1\x16\xEF\xD6\xE2" 400 172 "-" "-"
The above is from the same IP address over a period of time. Any insight into this is appreciated.