Recent Apache DOS advisory - problem applying the SetEnvIf/ RequestHeader workaround

Question

so one of the mitigations for this advisory was:

1) Use SetEnvIf or mod_rewrite to detect a large number of ranges and then either ignore the Range: header or reject the request.

Option 1: (Apache 2.0 and 2.2)

      # Drop the Range header when more than 5 ranges.
      # CVE-2011-3192
      SetEnvIf Range (,.*?){5,} bad-range=1
      RequestHeader unset Range env=bad-range

      # optional logging.

      CustomLog logs/range-CVE-2011-3192.log common env=bad-range

Now when I add this to my httpd.conf:

<IfModule mod_setenvif.c>
SetEnvIf Range (,.*?){5,} bad-range=1
RequestHeader unset Range env=bad-range

</IfModule>

I get this error when restarting Apache:

"Invalid command 'RequestHeader', perhaps misspelled or defined by a module not included in the server configuration"

The SetEvnIf module seems to be loaded.

What is wrong with that parameter?

Version is Apache/2.2.14 .

Link to the advisory is: http://mail-archives.apache.org/mod_mbox/httpd-announce/201108.mbox/browser

also, would Tomcat be vulnerable to this?

tia!

Answer 1

RequestHeader requires you to load mod_headers

Answer 2

as per DerfK's answer, you need to load mod_headers -- a la

LoadModule headers_module modules/mod_headers.so

in your conf file before the call to RequestHeader