Fake EV certificates used in Steam trade phishing attacks

An extremely convincing phishing attack that impersonates a multi-game skin trade bot appears to be using a fake Extended Validation TLS certificate to steal Steam accounts.

A fake Extended Validation certificate indicator.

The phishing site displaying a fake Extended Validation certificate indicator.

The ongoing phishing attack impersonates TradeIt.gg, which facilitates the trading of skins, weapons and other in-game commodities within popular games like CS:GO, TF2 and DOTA.

When a victim attempts to sign in through Steam to view their inventory on the spoof trading site, Steam's OpenID login form opens in a new window, clearly displaying its use of an Extended Validation certificate issued to Valve Corp...

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... or does it?

Extended Validation (EV) certificates offer the highest level of assurance that a website is being operated by a bona fide legal entity, which is why phishers like to make use of them whenever they can. EV certificates typically cost more than both domain and organisation validated certificates, as the issuance process involves a more stringent vetting process.

However, in this case, the fraudster has bypassed all of the expenses and vetting requirements by simply presenting a fake — yet very convincing — EV certificate indicator next to the address bar.

Closer inspection reveals that the Steam login page is also a spoof form, and it is not actually being displayed in a new browser window at all – it is being shown in an interactive, movable iframe that behaves like a window, allowing the fraudster to dress the "window" up however he likes. The tell-tale feature to look out for here is that the fake window cannot be maximized or moved beyond the boundaries of the spoof trading website.

Needless to say, when a victim submits their Steam credentials into this fake window, they will be stolen by a PHP script on the phishing site. The phisher can then monetize the compromised Steam account by selling it directly or by trading the victim's valuable in-game commodities.

Fraudsters have a long history of exploiting user interface redressing vulnerabilities to make better phishing attacks. More than 14 years ago, Netcraft's anti-phishing toolbar community discovered a particularly fiendish set of examples that exploited a vulnerability in Microsoft Internet Explorer, which allowed part of the webpage to be placed on top of the browser's own address bar.

An extremely convincing PayPal phishing attack that took place back in 2005. A bug in IE made it possible for page elements to be placed outside of the browser's viewport, allowing the attacker to place a fake paypal.com address on top of the browser's real address bar, thus hiding the true location of the fraudulent website.

An extremely convincing PayPal phishing attack that took place back in 2005. A bug in IE made it possible for page elements to be placed outside of the browser's viewport, allowing the attacker to place a fake paypal.com address on top of the browser's real address bar, thus hiding the true location of the fraudulent website.

There are often resurgences in these types of attack, but the certificate and address spoofing techniques are usually forced to change as browser security improves and becomes more restrictive. No doubt there will be more attacks like these in the future, as phishing site developers continue to evolve new tricks.

Netcraft has been protecting consumers against phishing attacks for 15 years. You can enjoy the best protection against the latest attacks, including this Steam trading attack, by installing the desktop Netcraft Extension and Netcraft app for Android.

Manufacturing.gov and White House security suffer under U.S. shutdown

Dozens more U.S. government websites have become inaccessible since last week, when Netcraft highlighted the impact of security certificates expiring during the federal shutdown.

As of today, more than 130 TLS certificates used by U.S. government websites have expired without being renewed. Some of these sites are now completely inaccessible in modern browsers due to their strict transport security policies.

The latest sites to be affected include some particularly prominent examples.

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Take https://manufacturing.gov, for instance. While Trump is keen to highlight the performance of U.S. manufacturing during his administration, the shutdown has meant that nobody was available to renew the site's TLS certificate when it expired on 14 January 2019. Consequently, https://manufacturing.gov is dead in the water, along with https://manufacturingusa.com which shares the same certificate.

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Furthermore, as https://manufacturing.gov appears in Chromium's HSTS preload list, visitors are unable to bypass the browser's security warnings, rendering the site unreachable.

manufacturing.gov appears in Chromium's HSTS preload list, which ensures that the website's strict transport policy will always be enforced, even when a browser has never visited the site before.

manufacturing.gov appears in Chromium's HSTS preload list, which ensures that the website's strict transport policy will always be enforced, even when a browser has never visited the site before. www.manufacturing.gov uses a different certificate, which is currently valid.

A White House subdomain at https://pages.mail.whitehouse.gov has also become unreachable. The certificate used by this site expired on 15 January 2019 and has not been renewed. This site is also covered by an effective preloaded HSTS policy.

White House security warnings in Mozilla Firefox.

White House security warnings in Mozilla Firefox.

Other notable websites to have been affected by expired certificates over the past five days include two FAA (Federal Aviation Authority) websites, a National Archives customer portal, the FFIEC (Federal Financial Institutions Examination Council) Anti-Money Laundering Infobase, several Department of Agriculture sites, and several governmental remote access services.

When the federal government restarts, the White House will need to renew its certificate for pages.mail.whitehouse.gov. The list price for a replacement DigiCert organisation validated certificate — similar to the expired one — could be up to $399 per year, or about 70 Big Macs.

.gov security falters during U.S. shutdown

Dozens of U.S. government websites have been rendered either insecure or inaccessible during the ongoing U.S. federal shutdown. These sites include sensitive government payment portals and remote access services, affecting the likes of NASA, the U.S. Department of Justice, and the Court of Appeals.

The DigiCert certificate used by this U.S. Court of Appeals website expired on 5 January 2019 and has not yet been renewed. The site provides links to a document filing system and PACER (Public Access to Court Electronic Records).

The DigiCert certificate used by this U.S. Court of Appeals website expired on 5 January 2019 and has not yet been renewed. The site provides links to a document filing system and PACER (Public Access to Court Electronic Records).

With around 400,000 federal employees currently furloughed, more than 80 TLS certificates used by .gov websites have so far expired without being renewed. To compound the situation, some of these abandoned websites can no longer be accessed due to strict security measures that were implemented long before the shutdown started.

One such example is https://ows2.usdoj.gov, a U.S. Department of Justice website which uses a certificate that expired in the week leading up the shutdown. The certificate has been signed by a trusted certificate authority, GoDaddy, but it has not been renewed since it expired on 17 December 2018.

All U.S. Department of Justice subdomains are covered by an HSTS policy. Combined with an expired TLS certificate, this currently makes it difficult for regular users to ignore the warnings and use the website.

All U.S. Department of Justice subdomains are covered by an HSTS policy. Combined with an expired TLS certificate, this currently makes it difficult for regular users to ignore the warnings and use the website.

In a twist of fate, the usdoj.gov domain — and all of its subdomains — are included in Chromium's HSTS preload list. This is a prudent security measure which forces modern browsers to only use secure, encrypted protocols when accessing the U.S. DoJ websites; however, it will also prevent users from visiting the HTTPS sites when an expired certificate is encountered. In these cases, modern browsers like Google Chrome and Mozilla Firefox deliberately hide the advanced option that would let the user bypass the warning and continue through to the site.

While this behaviour is bound to frustrate some users, in this case, security is arguably better than usability when you can't have both. If users were to ignore such warnings, they would be vulnerable to the type of man-in-the-middle attacks that TLS certificates were intended to combat.

However, only a few of the affected .gov sites implement correctly-functioning HSTS policies. Just a handful of the sites appear in the HSTS preload list, and only a small proportion of the rest attempt to set a policy via the Strict-Transport-Security HTTP header – but the latter policies will not be obeyed when they are served alongside an expired certificate, and so will only be effective if the user has already visited the sites before.

Consequently, most of the affected sites will display an interstitial security warning that the user will be able to bypass. This introduces some realistic security concerns, as task-oriented users are more likely to ignore these security warnings, and will therefore render themselves vulnerable to man-in-the-middle attacks.

For example, https://rockettest.nasa.gov/ is not included in the HSTS preload list, and its certificate expired on 5 January 2019. This causes browsers to display an interstitial security warning that users can ignore.

This NASA website is still using an expired certificate, but the domain does not appear on the HSTS preload list.  Users can therefore ignore the browser's warnings and proceed to the site.

This NASA website is still using an expired certificate, but the domain does not appear on the HSTS preload list. Users can therefore ignore the browser's warnings and proceed to the site.

The following example clearly demonstrates the potential dangers of ignoring browser security warnings. The certificate used by this Berkeley Lab .gov website at https://d2l.lbl.gov expired on 8 January 2019 (although Berkeley Lab was not affected by the shutdown) and has not yet been replaced. As there is no effective HSTS policy, users can ignore the browser's warnings and proceed to the login form.

Encouraging users to ignore browser warnings could make them more susceptible to man-in-the-middle attacks.

Encouraging users to ignore browser warnings could make them more susceptible to man-in-the-middle attacks. In this example, clicking next to the browser's address bar will explicitly advise the user not to enter any sensitive information, such as passwords – but anyone who really needs to use the site may foolishly end up doing so anyway.

With Donald Trump seemingly unwilling to compromise on his demands for a wall along the border with Mexico, and Democrats refusing to approve a budget containing $5.7bn for the wall, the hundreds of thousands of unpaid federal employees might not be the only ones hurting. As more and more certificates used by government websites inevitably expire over the following days, weeks — or maybe even months — there could be some realistic opportunities to undermine the security of all U.S. citizens.

The hidden “well-known” phishing sites

Thousands of phishing sites have been finding homes in special hidden directories on compromised web servers.

In the past month alone, over 400 new phishing sites were found hosted within directories named /.well-known/; but rather than being created by fraudsters, these special directories are already present on millions of websites.

A Microsoft Excel Online phishing site hosted in the /.well-known/ directory on a compromised web server. The phishing site piggybacks on the trust instilled by the compromised site's existing SSL certificate, which has not been revoked.

A Microsoft Excel Online phishing site hosted in the /.well-known/ directory on a compromised web server. The phishing site piggybacks on the trust instilled by the compromised site's existing SSL certificate, which has not been revoked.

The /.well-known/ directory acts as a URI path prefix for "well-known locations", as defined by IETF RFC 5785, and provides a way for both humans and automated processes to discover a website's policies and other information.

One of the most common legitimate uses of the /.well-known/ directory is to prove control over a domain. When a secure website uses the Automatic Certificate Management Environment (ACME) protocol to manage its SSL certificate, the issuer will verify ownership by checking for a unique token in /.well-known/acme-challenge/ or /.well-known/pki-validation/. Consequently, most of the phishing attacks that make use of the /.well-known/ directory have been deployed on sites that support HTTPS, using certificates issued by ACME-driven certificate authorities like Let's Encrypt and cPanel.

Due to the success of Let's Encrypt and ACME, millions of websites now have a /.well-known/ directory in their web root, although many website administrators may be oblivious to its presence – particularly if they did not create the directory themselves. The directory can also easily be overlooked, as a bare ls command will treat files or directories that start with a "." as hidden. These factors make /.well-known/ an ideal place to smuggle phish onto a compromised web server.

Around 3% of these phishing sites are mistakenly deployed in a /well-known/ directory, without a leading "." character. This mistake could stem from file system name limitations if the phishing kit was created on a Windows computer. This screenshot shows a phishing kit that would be installed in a /well-known/ directory when unzipped.

Around 3% of these phishing sites are mistakenly deployed in a /well-known/ directory, without a leading "." character. This mistake could stem from file system name limitations if the phishing kit was created on a Windows computer. This screenshot shows a Bank of America phishing kit that would be installed in a /well-known/ directory when unzipped.

Shared hosting platforms are particularly vulnerable to misuse if the file system permissions on the /.well-known/ directories are overly permissive, allowing one website to place content on another customer's website. Some of the individual servers involved in these attacks were hosting "well-known" phishing sites for multiple hostnames, which lends weight to this hypothesis.

Other well-known URIs

In addition to pki-validation and acme-challenge, there are 30 other widely recognised well-known URI suffixes defined by the IETF, W3C and others. For example, the EFF came up with the dnt-policy.txt suffix, which allows websites to announce their compliance with user opt-outs from tracking. The EFF's own Do Not Track Compliance Policy can be viewed at https://www.eff.org/.well-known/dnt-policy.txt.

Where multiple resources may be required, the well-known URI suffix is a directory rather than a file. For example, the IETF's Enrollment over Secure Transport RFC defines a set of resources that can be found under the /.well-known/est/ path.

Despite there being several other well-known URI directory suffixes, only pki-validation and acme-challenge have been used to host recent phishing sites. In fact, more than half of the phishing sites found under the /.well-known/ directory were planted within the subdirectories created by ACME clients (i.e. /.well-known/pki-validation/ and /.well-known/acme-challenge/), possibly making them even less likely to be noticed by the website administrators.

An Alibaba phishing site. More than half of all "well-known" phishing sites are installed in the directories used by ACME clients.

An Alibaba phishing site. More than half of all "well-known" phishing sites are installed in the directories used by ACME clients, although this does not necessarily mean the ACME clients are to blame.

The possible route of compromise is not always apparent in the aforementioned cases, but if there are any glaring security misconfigurations, a proposed new well-known URI suffix, security.txt, could come in handy. By placing contact details and disclosure policies in /.well-known/security.txt, website administrators can make it safer and easier for security researchers to reach out and report any problems they find.

Brazilian government providing warm waters for shoals of phish

Security holes in Brazilian government websites are still rife, with no fewer than eight different gov.br sites being compromised within the past week to host phishing attacks and hacking scripts. The situation does not seem to have improved much since two years ago, when we noticed a similar spate of phishing sites and malware hosted on gov.br domains, with evidence of some sites suffering repeated security compromises.

In one of this week's attacks, a gov.br domain was compromised to such an extent that the fraudsters were able to set up their own custom hostname, which was also configured to use HTTPS. The website, at account-verification-redirect-center.[redacted].gov.br, was then used to host a PayPal phishing site, which is still present at the time of writing.

Despite its rather dubious hostname, Let's Encrypt automatically issued an SSL certificate to account-verification-redirect-center.[redacted].gov.br earlier this week. Such foreseeable misuse evidently still does not prevent certificates being issued to phishing sites; but worse still, the fraudulent certificate has not yet been revoked.

The PayPal phishing site makes use of a ready-made phishing kit provided by SHADOW Z118. It includes several comprehensive "antibots" PHP scripts to avoid detection by search engines and enforcement agencies.

The PayPal phishing site makes use of a ready-made phishing kit provided by SHADOW Z118. It includes several comprehensive "antibots" PHP scripts to avoid detection by search engines and enforcement agencies.

To make matters worse, Netcraft found PHP shells on a few of the recently compromised gov.br sites. These backdoors provide fraudsters with almost complete access to the compromised web servers and make it easy for malware and phishing content to be uploaded at any time.

If the PHP shells are not removed, additional phishing sites are likely to appear on the affected sites, or they could even become infested with other PHP shells that will make the clean-up job much harder: If just one shell is overlooked, it can be used to replace all phishing content, malware and backdoors that the web server administrators had already deleted.

PayPal is still the most commonly targeted organisation in the latest attacks hosted by the Brazilian government, but other targets include Microsoft, Naver, Dropbox and the online dating site Match.com.

This OneDrive phishing site can steal Google, Outlook, AOL, Yahoo, Office 365, and other email credentials. The next form will steal the victim's phone number and backup email address.

This OneDrive phishing site can steal Google, Outlook, AOL, Yahoo, Office 365, and other email credentials. A second form steals the victim's phone number and backup email address.

Some of the phishing sites impersonate Microsoft's OneDrive service, using it as a convenient excuse to target Google, Outlook, AOL, Yahoo and other types of accounts from just a single attack. This particular attack could be rather harmful to businesses, as it gives victims the opportunity to log in with an Organizational Google Apps Account, which could result in the fraudster gaining access to sensitive company secrets.

Ironically, after the victim has been phished, he will be redirected to a PDF file on Google Drive entitled "The Business Owner's Guide to Wealth Management".

Ironically, after the victim has been phished, he will be redirected to a PDF file on Google Drive entitled "The Business Owner's Guide to Wealth Management".

All of the aforementioned phishing attacks were added to Netcraft's Phishing Site Feed, which is used by major web browsers and many leading anti-virus, content-filtering and web hosting companies.

LinkedIn certificate blunder leaves users LockedOut!

Many LinkedIn users were unable to access the professional networking website today after its administrators failed to renew a TLS certificate before it expired.

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The certificate in question was used by various country-specific LinkedIn websites such as https://uk.linkedin.com and https://de.linkedin.com. It expired at midday today, immediately preventing users from accessing the site via these hostnames.

The expired certificate was issued to us.linkedin.com, but was also valid for – and used by – dozens of other country-specific LinkedIn hostnames. The main site at www.linkedin.com was not affected.

The expired certificate was issued to us.linkedin.com, but was also valid for – and used by – dozens of other country-specific LinkedIn hostnames. The main site at www.linkedin.com was not affected.

The sites were still inaccessible a few hours after the problem manifested itself.

The sites were still inaccessible a few hours after the problem manifested itself.

Ironically, LinkedIn's better-than-average security made the expired certificate even more problematic. Most browsers will allow users to ignore certificate validation warnings — however unwise that may be — but the warnings cannot be ignored on these LinkedIn sites.

LinkedIn is in a minority of sites that make use of a security feature called HTTP Strict Transport Security. This feature protects HTTPS sites against trivial man-in-the-middle attacks, but unfortunately in this case, the additional security made the site completely unreachable for regular users.

Good security requires great care: Strict Transport Security is a good idea, but when a certificate expires, users cannot visit the site because browsers will not allow the warnings to be ignored.

Good security requires great care: Strict Transport Security is a good idea, but when a certificate expires, users cannot visit the site because browsers will not allow the warnings to be ignored when an active HSTS policy is in place.

Many modern browsers, such as Firefox and Chrome, simply do not allow users to add an exception when a site has an HSTS policy in place. LinkedIn's HSTS policy has a validity period of 30 days, which means that anyone who has visited the site within the past month would have been unable to add a certificate exception, and would therefore not be able to visit the site until LinkedIn renewed the certificate.

LinkedIn's expired certificate was renewed shortly before this article was published.