[squid-users] NULL characters

[Amos Jeffries]

On 27/05/2016 2:30 a.m., joe wrote:
> 2016/05/26 06:41:28 kid1| ctx: enter level  0:
> 'http://js.advert.mirtesen.ru/data/js/82090.js'
> 2016/05/26 06:41:28 kid1| WARNING: HTTP header contains NULL characters
> {Server: nginx
> Date: Thu, 26 May 2016 03:46:52 GMT
> Content-Type: application/javascript;charset=utf-8
> Transfer-Encoding: chunked
> Connection: close
> Vary: Accept-Encoding
...
> X-ShmCnt: 3
> Set-Cookie: nid}
> NULL
> {Server: nginx
> Date: Thu, 26 May 2016 03:46:52 GMT
...
> 2016/05/26 06:41:28 kid1| ctx: exit level  0
> 
> is it bad ?????
> 

It is both okay and bad.

The server is producing at least one null / 0x00 character where it
should not. The log shows it to be in the middle of a Set-Cookie header
and strangely have a whole other set of response headers following the
null. That is a sign of very broken server or server scripts. Normally
we see less broken scripts outputting null instead of end-of-line
characters. This one is nasty.


It is okay, because Squid is detecting the problem and is able to
prevent it causing damage.

It is still sort of bad because requests to this server or URL will
result in an error page being delivered to the user and nothing they or
you can do to fix it. Only the admin or webmaster of the server
producing that response can do anything.

Amos