200 html return to log4j exploit

Jay Caines-Gooby jay at gooby.org
Mon Dec 20 17:49:48 UTC 2021

The request is for your index page "GET / HTTP/1.1"; that's why your server
responded with 200 OK. The special characters are in the referer and
user-agent fields, as a log4j system would also try to interpolate these,
and thus be vulnerable to the exploit.

On Mon, 20 Dec 2021 at 04:02, lists at lazygranch.com <lists at lazygranch.com>

> I don't have any service using java so I don't believe I am subject to
> this exploit. Howerver I am confused why a returned a 200 for this
> request. The special characters in the URL are confusing.
> 200 - - [17/Dec/2021:02:58:02 +0000] "GET / HTTP/1.1" 706
> "${${lower:jndi}:${lower:rmi}://}"
> "${${lower:jndi}:${lower:rmi}://}" "-"
>     log_format  main  '$status $remote_addr - $remote_user
>     [$time_local] "$request" ' '$body_bytes_sent "$http_referer" '
>                       '"$http_user_agent" "$http_x_forwarded_for"';
> That is my log format from the nginx.conf.
> I now have a map to catch "jndi" in both url and agent. So far so good
> not that it matters much. I just like to gather IP addresses from
> hackers and block their host if it lacks eyeballs,
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Jay Caines-Gooby
jay at gooby.org
+44 (0)7956 182625
twitter, skype & aim: jaygooby
gtalk: jaygooby at gmail.com
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