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Re: nginx CVE-2013-0337 world-readable logs
From: Kurt Seifried <kseifried () redhat com>
Date: Sun, 24 Feb 2013 13:24:53 -0700

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On 02/24/2013 12:34 AM, gremlin () gremlin ru wrote:
On 22-Feb-2013 15:46:15 +0400, I wrote:

Some distros are affected.

Alas for them... But the solution is simple.

This is not just misconfiguration.

This issue isn't related to the nginx itself. However, I'd agree
that nginx could use restrictive mode for its' log files: +++
nginx-1.2.7/src/core/ngx_log.c @@ -325,7 +325,7 @@ -
NGX_FILE_DEFAULT_ACCESS); +  NGX_FILE_USR_GRP_ACCESS);

I've contacted the nginx team via their security-alert@ and got the
"won't fix" answer by Maxim Dounin:

We are fine with default permissions used for log files. If in a
particular configuration stricter permissions are required, this
may be done either by creating appropriate log files with needed
permissions, or by restricting access to a directory with log
files.

Although respecting the umask value could be a better solution (and
I'll try once again to convince the developers in that), the
developers' opinion is clear: pre-creating the logs is the expected
method to fix the ${subject}.



I somewhat disagree for the simple fact that web servers MUST log
sensitive information (e.g. GET strings) to be of any use. This goes
back to the discussion regarding programs such as gpg. Personally I
would rather see the log files (ALL log files for ALL programs
actually) created using a default permission that is safe (e.g. 0600
or 0660 if it writes to it with the group permissions), but can be
configured and easily overridden in a config file (e.g. nginx.conf) so
that people that have a legitimate need for world readable log files
can do so easily.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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