Curious HTTP GET commands ...

[jc at trillian.mit.edu (John Chambers)]

My apache access_log shows a number of requests starting 19 July, all
from different IP addresses, that look like:

"GET /default.ida?NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN%u9090%u6858%ucbd3%u7801%u9090%u6858%ucbd3%u7801%u9090%u6858%ucbd3%u7801%u9090%u9090%u8190%u00c3%u0003%u8b00%u531b%u53ff%u0078%u0000%u00=a  HTTP/1.0"

It's fairly obvious that  something  out  there  is  trying  to  take
advantage  of some soft of buffer overflow, though it doesn't seem to
be working.  It just gets  a  "Client  sent  malformed  Host  header"
message in the errlog. This doesn't seem to be nearly enough bytes to
overflow a buffer, anyway, since I've seen valid URLs (with  lots  of
form  params) that are much longer than this.  And it doesn't seem to
have any effect at all on the apache 1.3.17 that  I'm  running.   But
maybe  it  works with some servers.  Anyone have any idea what attack
this might be?  What is "default.ida"?

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