Cyber Criminals mimic any kind of business using multiple tricks. For example, fake invoices from Amazon or ricardo.ch, some security warning messages from PayPal, ebay or some customer service message from banks across the world.
In this case I'm going to talk about one interesting campaign currently happening against PayPal.
Initially a SCAM email like the one below is sent to the victim. The email contains an HTML file attached. If the enduser is lucky, the email will be detected as SPAM by the mail filters, but this has not been always the case. The HTML in all the cases were not detected as malicious by the AV. The HTML used in this post, which I have uploaded to VirusTotal, is only detected by 3 engines
Using some breakpoints I can extract the content of the variable BkozdlkPhvQy, which contains the final HTML that will be presented to the victim
This new HTML code can be extracted for further analysis.
There are several functions in the code which looks interesting. Moreover, I find referenced some URLs http://www.candidate7.net and https://www.paypal.com and some PHP code 9d681cd81c49939eb384d49051d7e272.php.
The first function referenced by var _0x3a657d is in charge of checking if the Credit Card number introduced is a valid one. If it it is not, it will redirect to www.paypal.com
Second function, Psumit() is in charge of sending the data through a POST request. All the data will be sent to the URL http://www.candidate7.net/9d681cd81c49939eb384d49051d7e272.php
Last function, _0x529953(), is in charge of performing more additional checks, it checks:
- that the address filled in the form is not empty
- that the month, year and CVV filled in the credit card details from the form is not empty and is not 0
- that the name filled is not empty
- if the country selected is US, the SSN and the Zip Code has the correct length
If all the conditions do not happen the browser is redirect to http://www.paypal.com. Otherwise, the data filled in the form is sent to http://www.candidate7.net/9d681cd81c49939eb384d49051d7e272.php. Below and example of the HTTP POST.
This is quite interesting as the criminals are taking care that they will only receive valid data thought the form so they do not need to check the data received.
After the data is sent through the POST, the PHP script redirects to http://www.paypal.com
As a test, I can request manually the resource directly with the IP and I'm redirected to PayPal as well.
Checking the domain candidate7.com I can see it has been created the day before the email was sent.
Whois Server Version 2.0
Domain names in the .com and .net domains can now be registered
with many different competing registrars. Go to http://www.internic.net
for detailed information.
Domain Name: CANDIDATE7.COM
Registrar: PDR LTD. D/B/A PUBLICDOMAINREGISTRY.COM
Sponsoring Registrar IANA ID: 303
Whois Server: whois.PublicDomainRegistry.com
Referral URL: http://www.publicdomainregistry.com
Name Server: NS1.DYNU.COM
Name Server: NS2.DYNU.COM
Name Server: NS3.DYNU.COM
Name Server: NS4.DYNU.COM
Name Server: NS5.DYNU.COM
Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Updated Date: 22-jul-2016
Creation Date: 20-jul-2016
Expiration Date: 20-jul-2017
>>> Last update of whois database: Sun, 24 Jul 2016 08:47:13 GMT <<<
The Registry database contains ONLY .COM, .NET, .EDU domains and
Domain Name: CANDIDATE7.COM
Registry Domain ID: 2044541489_DOMAIN_COM-VRSN
Registrar WHOIS Server: whois.publicdomainregistry.com
Registrar URL: www.publicdomainregistry.com
Updated Date: 2016-07-20T01:43:14Z
Creation Date: 2016-07-20T01:43:12Z
Registrar Registration Expiration Date: 2017-07-20T01:43:12Z
Registrar: PDR Ltd. d/b/a PublicDomainRegistry.com
Registrar IANA ID: 303
Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Registry Registrant ID:
Registrant Name: Alex Tankredi
Registrant Organization: N/A
Registrant Street: 289 rendang rd no 28b
Registrant City: kuala lumpur
Registrant State/Province: kl
Registrant Postal Code: 248195
Registrant Country: MY
Registrant Phone: +60.601848928124
Registrant Phone Ext:
Registrant Fax Ext:
Registrant Email: email@example.com
Registry Admin ID:
Admin Name: Alex Tankredi
Admin Organization: N/A
Admin Street: 289 rendang rd no 28b
Admin City: kuala lumpur
Admin State/Province: kl
Admin Postal Code: 248195
Admin Country: MY
Admin Phone: +60.601848928124
Admin Phone Ext:
Admin Fax Ext:
Admin Email: firstname.lastname@example.org
Registry Tech ID:
Tech Name: Alex Tankredi
Tech Organization: N/A
Tech Street: 289 rendang rd no 28b
Tech City: kuala lumpur
Tech State/Province: kl
Tech Postal Code: 248195
Tech Country: MY
Tech Phone: +60.601848928124
Tech Phone Ext:
Tech Fax Ext:
Tech Email: email@example.com
Under the same e-mail address, several other domains have been registered.
The domains used for this campaign candidate7.com, candidate7.net and candidate7.biz resolve to the same IP 220.127.116.11. The three off them have been registered around the same time. By the way, the IP 18.104.22.168 is a Tor node
And all the subdomains www.candidate7.com, www.candidate7.biz and www.candidate7.net resolve also to the same IP 22.214.171.124, which is the one that cyber threat actors are using to receive the data from the form.
This is what happens in essence:
- Cyber Threat Actors registered several domains across the same time. All of them with the same name resolving to the same IP.
- In a very short period of time after the registration of the new domains, all the SCAM emails are sent with an HTML attached. The HTML is obfuscated to avoid detection
- The HTML contains an HTTP form to steal the credit card data. This form only sends the data to the threat actors if the information is somehow valid and not faked.
- After the POST request, the user is redirected to the real PayPal website.
Once the domains are black listed, they again register new domains and proceed again from the step 1.
(More to come)