Full Disclosure mailing list archives
Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192)
From: bodik <bodik () civ zcu cz>
Date: Fri, 26 Aug 2011 13:26:52 +0200
Option 2: (Pre 2.2 and 1.3) # Reject request when more than 5 ranges in the Range: header. # CVE-2011-3192 # RewriteEngine on RewriteCond %{HTTP:range} !(bytes=[^,]+(,[^,]+){0,4}$|^$) # RewriteCond %{HTTP:request-range} !(bytes=[^,]+(?:,[^,]+){0,4}$|^$) RewriteRule .* - [F]^^ Better use this: RewriteEngine on RewriteCond %{HTTP:range} !(^bytes=[^,]+(,[^,]+){0,4}$|^$) [NC,OR] RewriteCond %{HTTP:request-range} !(^bytes=[^,]+(,[^,]+){0,4}$|^$) [NC] RewriteRule .* - [F] Because if you don't specify the [OR] apache will combine the rules making an AND (and you don't want this!). Also use NC=(nocase) to prevent the attacker upper casing "bytes=" (don't know if it will work.. but just to prevent)
in any case, i found very wierd behavior on some of our webservers. as we applied the first version of workaround, something about 15% of our webpages seems to be broken, but the rest of virtual hosts were working fine. I really dunno why, since LiveHeaders didn't show !any! ranges http header from my browser but still i was getting "Forbidden" response :( I'll digg in deeper (also to rewrite debug log) in the night because I can't reproduce it on other places ;( bodik _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Dirk-Willem van Gulik (Aug 25)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Anestis Bechtsoudis (Aug 26)
- <Possible follow-ups>
- Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Dirk-Willem van Gulik (Aug 26)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Carlos Alberto Lopez Perez (Aug 26)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) bodik (Aug 26)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) bodik (Aug 26)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Nikolay Kichukov (Aug 27)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Andrew Farmer (Aug 29)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Carlos Alberto Lopez Perez (Aug 26)
- Re: Advisory: Range header DoS vulnerability Apache HTTPD 1.3/2.x (CVE-2011-3192) Dirk-Willem van Gulik (Aug 26)