[Snort-users] Where to configure/change rules for this one?

Neil Dickey neil at ...1633...
Thu May 3 13:22:58 EDT 2001

"Ed Greshko" <Edward.M.Greshko at ...1974...> wrote:

>[**] spp_http_decode: IIS Unicode attack detected [**]
>05/03-23:12:18.641497 129.179.xx.xx:1171 ->
>TCP TTL:127 TOS:0x0 ID:2039 IpLen:20 DgmLen:484 DF
>***AP*** Seq: 0x6D4A2C44  Ack: 0x34EF9A9F  Win: 0x2238  TcpLen: 20
>As far as I can tell this is normal surfing by someone running Win2K English
>version connecting to a site here in Taiwan and reading Chinese site in Hong
>The messages don't appear to be coming from the included rules.

They aren't.  Look for a line in your configuration file that looks like this:

  preprocessor http_decode: 80 8080

Those entries are coming from the preprocessor.  You need to turn off the
"unicode" capability by changing the line to look like this:

  preprocessor http_decode: 80 8080 -unicode

Then reset Snort to get it to re-read the configuration files.

Best regards,

Neil Dickey, Ph.D.
Research Associate/Sysop
Geology Department
Northern Illinois University
DeKalb, Illinois

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