In June 2015, Trustwave issued an organisation-validated certificate for paypal-office.com, myaccount-paypal.com and paypal-sign.com that was used on a PayPal phishing site. The certificate was issued to an individual in India, Asha Shaikh, who may be the fraudster behind the phishing site, or perhaps one of the fraudster's victims. The phishing attack is now offline, but the certificate has yet to be revoked by Trustwave at the time of writing.

Rendered contents of phishing site found on www.paypal-office.com. The error message visible at the top of the page is a giveaway: the geo-location of the visitor's IP address failed, and it reveals the location of the files used to power the phishing site.

Certificate authorities typically sell certificates in three broad categories of assurance: domain-validated certificates simply validate control over a domain name; organisation-validated certificates include the identity of the organisation; and Extended Validation certificates increase the level of identity checking done to meet a recognised industry standard.

The difference between DV, OV, and EV certificates is sometimes subtle — many sources of consumer advice do not make the distinction between certificates that provide further identity information and those that only validate domain name ownership. For example, Google Chrome's help page states: "You can tell if a site is real if it has a valid TLS/SSL certificate".

Most certificates with deceptive domain names are domain-validated, though some appear to be organisation-validated. Many of the SSL certificates associated with CloudFlare's "Universal SSL" programme are ostensibly organisation-validated; however, the organisation being validated in this case is CloudFlare itself and not each individual customer.

An organisation-validated certificate for paypal-office.com shown in the Windows certificate viewer.

Rather than be processed automatically, as is possible with domain-validated certificates, most higher-assurance certificate requests will be reviewed by a human prior to issuance. This additional level of validation makes it all the more surprising that a request for a certificate containing "paypal" wasn't considered a high risk request, and consequently rejected after being subjected to increased scrutiny.

Trustwave offers a Relying Party warranty with its certificates, covering fraudulent credit card charges made by a Trustwave certificate holder. However, the warranty does not cover other types of fraud, meaning phishing for credentials or fraudulent payments using other payment methods are not covered. As a result, victims of this phishing attack will not be able to claim on this warranty, despite having their PayPal credentials stolen by a fraudster using a Trustwave certificate.

In just one month, certificate authorities have issued hundreds of SSL certificates for deceptive domain names used in phishing attacks. SSL certificates lend an additional air of authenticity to phishing sites, causing the victims' browsers to display a padlock icon to indicate a secure connection. Despite industry requirements for increased vetting of high-risk requests, many fraudsters slip through the net, obtaining SSL certificates for domain names such as banskfamerica.com (issued by Comodo), ssl-paypai-inc.com (issued by Symantec), and paypwil.com (issued by GoDaddy).

CloudFlare, a content delivery network that provides free "Universal SSL" to its customers, is a hotspot for deceptive certificates, accounting for 40% of SSL certificates used by phishing attacks with deceptive domain names during August 2015. CloudFlare's Universal SSL certificates are provided in partnership with Comodo, and CloudFlare also use GlobalSign certificates for some of its customers. CloudFlare's flexible SSL option also appeals to fraudsters, offering a padlock in victims' browsers without the need for attackers to set up SSL on their web servers.

A screenshot of a PayPal phishing site using a widely trusted SSL certificate valid for www.pay-pal.co.com. The certificate is a CloudFlare Universal SSL certificate issued by Comodo. The certificate has not been revoked; however, the phishing site is no longer available.

Websites that use TLS (the successor to SSL) are marketed as being trustworthy and operated by legitimate organisations. Consumers have been trained to "look for the padlock" in their browser before submitting sensitive information to websites, such as passwords and credit card numbers. While the reality is more nuanced, the data submitted to a phishing site using TLS is protected from eavesdroppers. However, a displayed padlock alone does not imply that a site using TLS can be trusted, or is operated by a legitimate organisation.

A screenshot of a NatWest phishing site using a widely trusted SSL certificate valid for natwestnwolb.co.uk. (nwolb stands for NatWest online banking. The legitimate NatWest online banking service is available at www.nwolb.com.)

A screenshot of a Bank of America phishing site using a widely trusted SSL certificate valid for banskfamerica.com.

The following table lists some examples of deceptive SSL certificates that have been used to conduct phishing attacks, along with their Domain Registration Risk scores:

* The certificates that CloudFlare issues to its customers are ostensibly organisation-validated, as they contain CloudFlare's company name and address. However, the customer domains themselves are only domain-validated.

The CA/Browser Forum's Baseline Requirements – a set of rules that publicly-trusted certificate authorities are expected to follow – require that high-risk domain names that may be used for fraud or phishing are subjected to additional verification:

High Risk Certificate Request: A Request that the CA flags for additional scrutiny by reference to internal criteria and databases maintained by the CA, which may include names at higher risk for phishing or other fraudulent usage.

The CA SHALL develop, maintain, and implement documented procedures that identify and require additional verification activity for High Risk Certificate Requests prior to the Certificate’s approval.

Despite this requirement, many major certificate authorities issue SSL certificates for deceptive domains used in phishing attacks. Notable exceptions include DigiCert and Entrust, neither of which issue domain-validated certificates.

A pie chart showing SSL certificates containing a deceptive domain name that were used in phishing attacks during August 2015, split by certificate authority. CloudFlare and non-CloudFlare certificates are shown separately.

Certificate authorities commonly provide SSL certificates at three different levels of assurance:

• Domain validated (DV)
  Certificate authorities only have to check that the certificate's applicant controls the domain name contained in a DV certificate. These certificates are typically the cheapest option, and can be had for free or be purchased for less than $10. Let's Encrypt is planning to offer free, automatically-issued DV certificates starting later in 2015.
• Organisation validated (OV)
  In addition to validating the domain name in the certificate, the identity of the person or organisation applying for an OV certificate is also verified by the certificate authority and included in the certificate. Most browsers do not treat OV certificates any differently to DV certificates.
• Extended validation (EV)
  Like OV certificates, the identity of the organisation applying for an EV certificate is verified by the certificate authority. However, the verification is more stringent. EV certificates also receive different treatment in major web browsers – the address bar is either partially or completely coloured green and the requesting organisation's name and country are displayed next to the padlock. The requirements for EV certificates in Chrome are changing, with many certificate authorities caught out by recent changes to require Certificate Transparency.

The requirement to perform additional verification of high risk certificate requests applies to all levels of assurance. However, DV certificates are often issued completely automatically within minutes, making it easy for fraudsters to obtain DV certificates for deceptive domain names.

Several certificate authorities offer free trial certificates with shorter validity periods. For example, Comodo offers free 90 day certificates, which have been used by a number of SSL phishing attacks. Symantec also offers free 30 day certificates through its GeoTrust brand. The short validity periods are ideal for fraudsters as phishing attacks themselves typically have short lifetimes.

Netcraft's Domain Registration Risk service automatically identifies deceptive domain names constructed using such tricks. The service calculates a risk score between 0 (low risk) and 10 (high risk) for each domain name, which represents the likelihood that the domain name will be used to carry out a phishing attack. Certificate authorities can make use of the service to determine if a domain name is likely to be used for fraudulent purposes before issuing the certificate.

The service can be provided as an API that mimics a Certificate Transparency log server for ease of integration with your existing certificate issuance process. The same API can also be used with Netcraft's certificate compliance checking service, which can identify certificates before they are issued that do not conform with the CA/B Forum's Baseline Requirements or its EV Guidelines.

Fraudsters are stealing eBay usernames and passwords using phishing pages hosted on eBay's own infrastructure. One of these pages, targeting German users, is shown below:

An eBay phishing form hosted on eBay's own infrastructure. The form contents are submitted to an external domain in Russia.

The convincing appearance of the spoof login form is bolstered by the fact that it is hosted on a genuine eBay domain, ebaydesc.com. This domain is ordinarily used to host descriptions for eBay listings which are displayed within iframes on eBay listing pages.

In this case, the corresponding eBay listing has already been deleted, although the phishing content within the listing's description can still be viewed by browsing directly to the relevant URL on vi.vipr.ebaydesc.com. Consequently, the attack is still live and capable of stealing credentials from eBay users.

The URL of the credential-stealing script is only momentarily visible in the address bar before the victim is redirected to the genuine eBay site.

When a victim enters his username and password into the form, both values are submitted to a PHP script hosted on a server in Russia. After stealing the credentials, this script then redirects the victim to the genuine ebay.de login page, which reports that the username or password was incorrect.

After the victim's credentials are stolen, he is redirected to the real eBay login page. Note that the username field has been automatically populated with the username stolen by the fraudster.

This error message might cause the victim to become suspicious enough to look at the browser's address bar, to check he is on the right website; but it will already be too late at this point – his credentials will have already been stolen, and because his browser will now be showing ebay.de in the address bar, he may not even realise that his credentials have just been sent to a web server in Russia. There is consequently little chance of the victim reacting by changing his password, allowing the fraudster to take full advantage of the stolen credentials at his leisure.

The website involved in collecting the stolen credentials has also been used to host other phishing attacks targeting German-speaking consumers, including sites impersonating PayPal, Apple, and mobile.de.

In an attempt to evade detection by eBay and others, the fraudster has obfuscated the HTML source of his eBay phishing form. This makes it impossible to find such a listing by searching for any of the words that appear in the description, yet the rendered results appear as normal when viewed in a web browser.

The obfuscated HTML source used by the phishing content hosted by eBay.

Allowing anyone to insert arbitrary HTML and malicious scripts into a listing's description gives plentiful opportunities to would-be fraudsters, particularly as this weakness has been exploited to carry out similar attacks against eBay users in the past. Last year, Netcraft reported on fraudsters injecting malicious JavaScript into eBay listings to set up man-in-the-middle attacks against car buyers, and similar JavaScript redirection techniques have continued to be exploited throughout 2015.

These phishing methods can be much more successful than traditional phishing attacks (where content is hosted solely on an unrelated domain). The techniques employed in these latest attacks are not permitted under eBay's HTML and JavaScript policy; however, a fraudster intent on stealing passwords is not going to be deterred by words alone.