---+ Security Alert: Denial-of-Service vulnerability in MAKETEXT macro
This advisory alerts you of a potential security issue with your Foswiki installation. A vulnerability has been reported against the Foswiki %MAKETEXT{}% macro, which Foswiki uses to provide translations. Because of this vulnerability it may be possible for a user to exhaust the server of memory and swap space using a crafted %MAKETEXT% macro. If your wiki allows commenting by users without first logging in, then it may be possible for such an anonymous user to exploit this vulnerability.
---++ Severity Level
1
The severity level was assigned by the Foswiki Community.SecurityTaskTeam as documented in Development.SecurityAlertProcess
---++ Vulnerable Software Versions
---++ MITRE Name for this Vulnerability
The Common Vulnerabilities and Exposures project has assigned the name CVE-2012-6330 to this vulnerability, see http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-6330
---++ Attack Vectors
Editing wiki pages and HTTP POST requests towards a Foswiki server with enabled localization (typically port 80/TCP). Typically, prior authentication is necessary.
A crafted %MAKETEXT{}% macro can consume all memory leading to a possible system crash. Any user with the authority to edit a topic, comment on a topic, or execute the Foswiki rendering code (eg. The RenderPlugin) can take advantage of the vulnerability.
---++ Impact
Exhaustion of system swap space and memory, leading to Denial of Service
A critical remote code execution vulnerability ([[SecurityAlert-CVE-2012-6329]]) is also addressed by the patches in this alert. Refer to that alert for further information.
---++ Details
A crafted %MAKETEXT{}% macro can cause multiple issues:
* Execute arbitrary code on the server by passing unsanitized strings to Locale::Maketext. (CVE-2012-6329)
* Consume memory and swap space resulting in potential lockup or crash due to %<nop>MAKETEXT{}% not validating the parameter numbers supplied in the =[_nnn]= tokens. (CVE-2012-6330)
* Cause an exception within Foswiki, also due to invalid parameters in =[_nnn]= tokens
---++ Countermeasures
One of the following should be done as soon as possible.
* Manually Apply hotfix (see patch below). __or__
* Apply the [[Extensions.PatchItem12285Contrib][http://foswiki.org/Extensions/PatchItem12285Contrib]] to your Foswiki 1.1.x system (Does not apply to Foswiki 1.0.x) __or__
* The foswiki debian package has already been updated with the hotfix - use your preferred package management tool to update to foswiki 1.1.6-2
Note that Disable ={UserInerfaceInternationalization}= in your LocalSite.cfg will avoid the code execution vulnerability reported as [[SecurityAlert-CVE-2012-6329]] but this other issue will still remain.
Upgrade to the latest patched production Download.FoswikiRelease01x01x07 once released
*The Foswiki patch fixes other issues with the =%MAKETEXT%= macro beyond the out of memory issue. Even with this patch installed, we recommend that a new Locale::Maketext is also upgraded to 1.23 or later*
---++ Hotfix for Foswiki Release 1.1.0 - 1.1.6
Install [[Extensions.PatchItem12285Contrib]], and verify that the patch has been applied to lib/Foswiki/Macros/MAKETEXT.pm. The extension will attempt to apply two patches, and should report that 1 file was patched. Only one of the patches will match your system. This patch fixes both [[SecurityAlert-CVE-2012-6329]] and [[SecurityAlert-CVE-2012-6330]].
Running Post-install exit for PatchItem12285Contrib...
Processing /var/www/data/Foswiki-1.1.1/working/configure/patch/Item12285-001.patch
...
MD5 Matched - applying patch version Foswiki 1.1.0 - 1.1.2.
Update successful for /var/www/data/Foswiki-1.1.0/lib/Foswiki/Macros/MAKETEXT.pm
.
1 file patched
...
Processing /var/www/data/Foswiki-1.1.1/working/configure/patch/Item12285-002.patch
...
No files matched patch signatures
On a properly patched system, =%MAKETEXT{" [_101] "}%= should return an error. Excessive parameter number 101, MAKETEXT rejected.
Note that this Contrib will also install the Extensions.PatchFoswikiContrib as a prerequisite. !PatchFoswikiContrib patches the Extensions installer to accept the new style version strings used for modules released as of 1.1.6.
---++ Hotfix for Foswiki Archived Release 1.0.0-1.0.10
This patch fixes both [[SecurityAlert-CVE-2012-6329]] and [[SecurityAlert-CVE-2012-6330]].
This release should be manually patched. In =Foswiki.pm=, in the =sub MAKETEXT=
--- Foswiki.pm 2010-01-17 09:16:20.000000000 -0500
+++ Foswiki.pm.new 2012-12-10 10:06:37.389129654 -0500
@@ -4200,6 +4200,9 @@
$str =~
s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ $max = $2 if ($2 > $max); "[$1]"/ge;
+ return "Illegal parameter number" if ($max > 100);
+ $str =~ s#\\#\\\\#g;
+
# get the args to be interpolated.
my $argsStr = $params->{args} || "";
---++ Manual patch for Foswiki Release 1.1.0 -> 1.1.2
Installing the Extensions.PatchItem12285Contrib is the best way to patch your system - you can however see the patch we apply here. This patch fixes both [[SecurityAlert-CVE-2012-6329]] and [[SecurityAlert-CVE-2012-6330]]:
~~~PATCH 72c86f0c71519caf6d26efbe174739f6 lib/Foswiki/Macros/MAKETEXT.pm (Foswiki 1.1.0 - 1.1.2)
--- /home/gac/Foswiki/Foswiki-1.1.0/lib/Foswiki/Macros/MAKETEXT.pm 2010-10-04 11:26:34.000000000 -0400
+++ lib/Foswiki/Macros/MAKETEXT.pm 2012-12-11 11:26:04.034507184 -0500
@@ -4,9 +4,19 @@
use strict;
use warnings;
+use Locale::Maketext;
+my $escape =
+ ( $Foswiki::cfg{UserInterfaceInternationalisation}
+ && $Locale::Maketext::VERSION
+ && $Locale::Maketext::VERSION < 1.23 );
+
sub MAKETEXT {
my ( $this, $params ) = @_;
+ my $max;
+ my $min;
+ my $param_error;
+
my $str = $params->{_DEFAULT} || $params->{string} || "";
return "" unless $str;
@@ -18,15 +28,22 @@
$str =~ s/~~\[/~[/g;
$str =~ s/~~\]/~]/g;
+ $max = 0;
+ $min = 1;
+ $param_error = 0;
+
# unescape parameters and calculate highest parameter number:
- my $max = 0;
- $str =~ s/~\[(\_(\d+))~\]/ $max = $2 if ($2 > $max); "[$1]"/ge;
+ $str =~ s/~\[(\_(\d+))~\]/_validate($1, $2, $max, $min, $param_error)/ge;
$str =~
-s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ $max = $2 if ($2 > $max); "[$1]"/ge;
+s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ _validate($1, $2, $max, $min, $param_error)/ge;
+ return $str if ($param_error);
# get the args to be interpolated.
my $argsStr = $params->{args} || "";
+ # Escape any escapes.
+ $str =~ s#\\#\\\\#g if ($escape); # escape any escapes
+
my @args = split( /\s*,\s*/, $argsStr );
# fill omitted args with zeros
@@ -47,6 +64,26 @@
return $result;
}
+sub _validate {
+
+ #my ( $contents, $number, $max, $min, $param_error ) = @_
+
+ $_[2] = $_[1] if ( $_[1] > $_[2] ); # Record maximum param number
+ $_[3] = $_[1] if ( $_[1] < $_[3] ); # Record minimum param number
+
+ if ( $_[1] > 100 ) {
+ $_[4] = 1; # Set error flag
+ return
+"<span class=\"foswikiAlert\">Excessive parameter number $_[2], MAKETEXT rejected.</span>";
+ }
+ if ( $_[1] < 1 ) {
+ $_[4] = 1; # Set error flag
+ return
+"<span class=\"foswikiAlert\">Invalid parameter <code>\"$_[0]\"</code>, MAKETEXT rejected.</span>";
+ }
+ return "[$_[0]]"; # Return the complete bracket parameter without escapes
+}
+
1;
__END__
Foswiki - The Free and Open Source Wiki, http://foswiki.org/
---++ Manual patch for Foswiki Release 1.1.3 -> 1.1.6
Installing the Extensions.PatchItem12285Contrib is the best way to patch your system - you can however see the patch we apply here This patch fixes both [[SecurityAlert-CVE-2012-6329]] and [[SecurityAlert-CVE-2012-6330]]:
~~~PATCH 160f04fc478c5f9b81d2ef6c9e614074 lib/Foswiki/Macros/MAKETEXT.pm (Foswiki 1.1.3 - Foswiki 1.1.6)
--- lib/Foswiki/Macros/MAKETEXT.pm 2012-12-11 10:51:12.959268829 -0500
+++ lib/Foswiki/Macros/MAKETEXT.pm.new 2012-12-11 10:37:31.674486503 -0500
@@ -4,9 +4,19 @@
use strict;
use warnings;
+use Locale::Maketext;
+my $escape =
+ ( $Foswiki::cfg{UserInterfaceInternationalisation}
+ && $Locale::Maketext::VERSION
+ && $Locale::Maketext::VERSION < 1.23 );
+
sub MAKETEXT {
my ( $this, $params ) = @_;
+ my $max;
+ my $min;
+ my $param_error;
+
my $str = $params->{_DEFAULT} || $params->{string} || "";
return "" unless $str;
@@ -18,15 +28,22 @@
$str =~ s/~~\[/~[/g;
$str =~ s/~~\]/~]/g;
+ $max = 0;
+ $min = 1;
+ $param_error = 0;
+
# unescape parameters and calculate highest parameter number:
- my $max = 0;
- $str =~ s/~\[(\_(\d+))~\]/ $max = $2 if ($2 > $max); "[$1]"/ge;
+ $str =~ s/~\[(\_(\d+))~\]/_validate($1, $2, $max, $min, $param_error)/ge;
$str =~
-s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ $max = $2 if ($2 > $max); "[$1]"/ge;
+s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ _validate($1, $2, $max, $min, $param_error)/ge;
+ return $str if ($param_error);
# get the args to be interpolated.
my $argsStr = $params->{args} || "";
+ # Escape any escapes.
+ $str =~ s#\\#\\\\#g if ($escape); # escape any escapes
+
my @args = split( /\s*,\s*/, $argsStr );
# fill omitted args with empty strings
@@ -47,6 +64,26 @@
return $result;
}
+sub _validate {
+
+ #my ( $contents, $number, $max, $min, $param_error ) = @_
+
+ $_[2] = $_[1] if ( $_[1] > $_[2] ); # Record maximum param number
+ $_[3] = $_[1] if ( $_[1] < $_[3] ); # Record minimum param number
+
+ if ( $_[1] > 100 ) {
+ $_[4] = 1; # Set error flag
+ return
+"<span class=\"foswikiAlert\">Excessive parameter number $_[2], MAKETEXT rejected.</span>";
+ }
+ if ( $_[1] < 1 ) {
+ $_[4] = 1; # Set error flag
+ return
+"<span class=\"foswikiAlert\">Invalid parameter <code>\"$_[0]\"</code>, MAKETEXT rejected.</span>";
+ }
+ return "[$_[0]]"; # Return the complete bracket parameter without escapes
+}
+
1;
__END__
Foswiki - The Free and Open Source Wiki, http://foswiki.org/
---++ Action Plan with Timeline
* 2012-12-05 - The Locale::Maketext vulnerability was discussed on the !Perl5Porters email list, triggered review of Foswiki code.
* 2012-12-05 - Patched version (1.23) of Locale::Maketext is released.
* 2012-12-08 - The [_999999] !DoS issue identified and sent to foswiki security list.
* 2012-12-09 - The "remote execution" vulnerability in Locale::Maketext was confirmed on Foswiki.
* 2012-12-09 - Requested the CVE from MITRE.
* 2012-12-09 - !TWiki notified of the Vulnerability.
* 2012-12-10 - Developer fixes code (George Clark) and security team validates the fixes.
* 2012-12-10 - [[Extensions.PatchItem12285Contrib]] released for Foswiki 1.1.x
* 2012-12-10 - Security team creates advisory with hotfix. Announcement delayed for coordination with TWiki (George Clark)
* 2012-12-12 - Updated Debian packages released (Sven Dowideit)
* 2012-12-12 - Send alert to foswiki-announce and foswiki-discuss mailing lists ( )
* 2012-12-14 - Publish advisory in Support web and update all related topics ( )
* 2012-12-14 - Reference to public advisory on Download page and Known Issues ( )
* 2012-xx-xx - Release Manager builds patch release ( )
* 2012-xx-xx - Issue a public security advisory ([email protected], [email protected], [email protected], [email protected], [email protected]) ( )
* Set ALLOWTOPICCHANGE = Main.SecurityGroup