Bangladesh government exporting live phish

Bangladesh is one of the world's largest producers of fish; but lately, its government has also become an inadvertent exporter of phish.

Over the past week, several phishing sites have popped up on Bangladeshi government websites, under the .gov.bd second-level domain. These fraudulent sites have been used in phishing attacks against customers of Wells Fargo bank, Google, AOL, and other email providers.

One of the phishing sites currently using a .gov.bd domain is hosted on a website belonging to the Bandarban Technical Training Center in Bangladesh. This site imitates Google Docs in an attempt to steal victims' email credentials, whichever mail providers they use.

One of the phishing sites currently using a .gov.bd domain is hosted on a website belonging to the Bandarban Technical Training Center in Bangladesh. The fraudulent content imitates Google Docs in an attempt to steal victims' email credentials, whichever mail providers they use.

Domain name registrations under .gov.bd are restricted to government-related entities in Bangladesh, although it is unlikely that the government is directly responsible for these attacks. As with most phishing sites, the fraudulent content has probably been placed on these government sites by remote hackers; nonetheless, this would make the Bangladesh government at least responsible for poor security.

The vast majority of websites under .gov.bd are hosted within Bangladesh, but the apparently-compromised server involved in these attacks is one of a few that are hosted in the United Kingdom, on a static IP address used by the hosting company Nibs Solutions. No Bangladeshi servers are currently serving phishing sites from .gov.bd domains.

After more than a week since this spate of phishing attacks started appearing on UK-hosted .gov.bd sites, none of the fraudulent content has been removed. The presence of multiple live phishing sites on the affected server, and the fact that the previous compromises have not yet been cleaned up, suggests that whatever security vulnerabilities might have affected the server are yet to be resolved.

Detected just over a week ago, the oldest phishing site in this spate of attacks targets Wells Fargo customers and remains accessible today on the Jessore Technical Training Center website at jessorettc.gov.bd. This training center was established by the Government of the People's Republic of Bangladesh in 2004, hence its eligibility to use the .gov.bd domain.

Detected just over a week ago, the oldest phishing site in this spate of attacks targets Wells Fargo customers and remains accessible today on the Jessore Technical Training Center website at jessorettc.gov.bd. This training center was established by the Government of the People's Republic of Bangladesh in 2004, hence its eligibility to use the .gov.bd domain.

Bangladesh has a relatively small presence on the web, with just over 30,000 websites making use of the entire .bd country code top-level domain. However, the ratio of phishing incidents to sites is quite high at roughly 1 in 100.

Users of the Netcraft anti-phishing extension are already protected from these attacks, including the examples shown above, even though the fraudulent content has not yet been removed by the sites' administrators.

Most Reliable Hosting Company Sites in April 2016

Rank Performance Graph OS Outage
hh:mm:ss
Failed
Req%
DNS Connect First
byte
Total
1 Datapipe Linux 0:00:00 0.000 0.160 0.012 0.024 0.031
2 Qube Managed Services Linux 0:00:00 0.000 0.153 0.058 0.117 0.117
3 CWCS Linux 0:00:00 0.000 0.189 0.070 0.142 0.143
4 Pair Networks FreeBSD 0:00:00 0.004 0.246 0.070 0.143 0.143
5 GoDaddy.com Inc Linux 0:00:00 0.009 0.257 0.010 0.024 0.025
6 XILO Communications Ltd. Linux 0:00:00 0.009 0.222 0.063 0.127 0.127
7 Kattare Internet Services Citrix Netscaler 0:00:00 0.009 0.517 0.114 0.228 0.228
8 LeaseWeb Linux 0:00:00 0.013 0.351 0.029 0.055 0.055
9 Hyve Managed Hosting Linux 0:00:00 0.013 0.222 0.060 0.120 0.120
10 Aspserveur Linux 0:00:00 0.013 0.343 0.077 0.326 0.471

See full table

Datapipe had the most reliable hosting company site in April, responding to all of Netcraft's requests. Datapipe's performance has seen it appear in the top ten every month so far in 2016, continuing a streak which has placed the company in the top ten 11 times in the past 12 months. Datapipe provides hosting services out of a number of data centres in Europe, Asia and North America. In April, Datapipe announced that it would be partnering with Singapore's largest electronics retailer to ensure the scalability of the latter's online infrastructure.

Qube had the second most reliable hosting company site. As with Datapipe, Qube's site responded to all of Netcraft's requests, but was fractionally slower to do so. Qube's performance is also consistent: the company has appeared in the top ten 9 times over the last 12 months.

CWCS achieved third place in April, also with a 100% response rate, albeit with an average connect time that was marginally slower than both Datapipe and Qube's. CWCS provides shared and managed hosting solutions, with data centre facilities in England and North America, and counts organisations such as KPMG and the University of York amongst its clients.

Linux is once again the most popular choice of operating system with hosting companies: eight out of the top ten companies in April hosted their websites on Linux machines. Kattare Internet Services and Pair Networks were the only two exceptions, using a Citrix Netscaler device and FreeBSD respectively.

Netcraft measures and makes available the response times of around forty leading hosting providers' sites. The performance measurements are made at fifteen minute intervals from separate points around the internet, and averages are calculated over the immediately preceding 24 hour period.

From a customer's point of view, the percentage of failed requests is more pertinent than outages on hosting companies' own sites, as this gives a pointer to reliability of routing, and this is why we choose to rank our table by fewest failed requests, rather than shortest periods of outage. In the event the number of failed requests are equal then sites are ranked by average connection times.

Information on the measurement process and current measurements is available.

Hook, like and sinker: Facebook serves up its own phish

Fraudsters are abusing Facebook's app platform to carry out some remarkably convincing phishing attacks against Facebook users.

A phishing site displayed on the real Facebook website.

A phishing site displayed on the real Facebook website.

Masquerading as a Facebook Page Verification form, this phishing attack leverages Facebook's own trusted TLS certificate that is valid for all facebook.com subdomains. This makes the page appear legitimate, even to many seasoned internet users; however, the verification form is actually served via an iframe from an external site hosted by HostGator. The external website also uses HTTPS to serve the fraudulent content, so no warnings are displayed by the browser.

The phishing attack does not require the victim to be already logged in.

The phishing attack does not require the victim to be already logged in.

This phishing attack works regardless of whether the victim is already logged in, so there is little chance of a victim being suspicious of being asked to log in twice in immediate succession.

The source code of the phishing content reveals that it sends the stolen credentials directly to the fraudster's website.

The source code of the phishing content reveals that it sends the stolen credentials directly to the fraudster's website.

To win over anyone who remains slightly suspicious, the phishing site always pretends that the first set of submitted credentials were incorrect. A suspicious user might deliberately submit an incorrect username and password in order to test whether the form is legitimate, and the following error message could make them believe that the credentials really are being checked by Facebook.

The phishing site always pretends the first submitted credentials are incorrect.

The phishing site always pretends the first submitted credentials are incorrect. Note that it now also asks for the victim's date of birth.

Those who were slightly suspicious might then believe it is safe to enter their real username and password. Anyone else who had already entered the correct credentials would probably just think they had made a mistake and try again. After the second attempt, the phishing site will act as if the correct credentials had been submitted:

On the second attempt, the phishing site will ask the victim to wait up to 24 hours.

On the second attempt, the phishing site will ask the victim to wait up to 24 hours.

The final response indicates that the victim will have to wait up to 24 hours for their submission to be approved. Without instant access to the content they were trying to view, the victim will probably carry on doing something else until they receive the promised email notification.

But of course, this email will never arrive. By this point, the fraudster already has the victim's credentials and is just using this tactic to buy himself some time. He can either use the stolen Facebook credentials himself, or sell them to others who might monetize them by posting spam or trying to trick victims' friends into helping them out of trouble by transferring money. If more victims are required, then the compromised accounts could also be used to propagate the attack to thousands of other Facebook users.

Some of Facebook's security settings.

Some of Facebook's security settings.

However, Facebook does provide some features that could make these attacks harder to pull off. For example, if login alerts are enabled, the victim will be notified that their account has been logged into from a different location – this might at least make the victim aware that something untoward is going on. Although not enabled by default, users can completely thwart this particular attack by activating Facebook's login approvals feature, which requires a security code to be entered when logging in from unknown browsers. Only the victim will know this code, and so the fraudster will not be able to log in.

April 2016 Web Server Survey

In the April 2016 survey we received responses from 1,083,252,900 sites and 5,800,222 web-facing computers. This reflects a gain of nearly 80 million sites and 18,100 computers.

This is the largest number of sites the survey has ever seen, beating the previous maximum of 1,028,932,208 in October 2014. The number of web-facing computers is also at its largest, although this total has generally risen much more steadily than the number of sites.

Microsoft was the only major vendor to gain sites this month, and so it was solely responsible for this month's total reaching its highest value ever. Apache lost 33 million sites, while nginx and Google suffered much smaller losses. Many of the 124 million additional sites using Microsoft IIS are aimed at a Chinese audience. Several million are served from just a handful of IP addresses, using either IIS 6.0 or 7.5.

However, this proliferation of new Microsoft-powered websites is largely driven by automated processes. Many are "spam" sites that use link farming techniques to attract traffic. Although Microsoft's website count grew by a remarkable 38.9% in April, it lost 12,100 web-facing computers. High quality websites that attract genuine repeat traffic tend to have a very low number of sites per computer compared with the computers that are involved in link farming, which sometimes host millions of automatically-generated sites each. Corroborating this further, Microsoft suffered a loss of 341,000 active sites this month, taking its total down by 2.0%.

Meanwhile, nginx continued its relentless growth. It gained 19,500 web-facing computers this month (+2.4%), was the only major vendor to increase its active sites count, and increased its share within the top-million websites by 0.49 percentage points.

nginx is particularly prominent at Amazon and DigitalOcean, with the two hosting companies accounting for more than 25% of all nginx computers. In particular, nginx is the most commonly used server at DigitalOcean, being used by just under half of its web-facing droplets. At Amazon, despite its large share of all nginx computers, Apache is more than twice as common, with nginx only used on a quarter of EC2 instances.

Total number of websites

Web server market share

DeveloperMarch 2016PercentApril 2016PercentChange
Microsoft317,761,31831.65%441,470,89440.75%9.10
Apache325,285,18532.40%292,043,54826.96%-5.44
nginx143,464,29314.29%143,349,43913.23%-1.06
Google20,790,7672.07%20,597,6051.90%-0.17
Continue reading

Most Reliable Hosting Company Sites in March 2016

Rank Performance Graph OS Outage
hh:mm:ss
Failed
Req%
DNS Connect First
byte
Total
1 Qube Managed Services Linux 0:00:00 0.000 0.148 0.058 0.118 0.118
2 Netcetera Linux 0:00:00 0.000 0.078 0.082 0.166 0.166
3 Datapipe Linux 0:00:00 0.008 0.158 0.012 0.024 0.031
4 Kattare Internet Services Citrix Netscaler 0:00:00 0.008 0.518 0.116 0.231 0.231
5 GoDaddy.com Inc Linux 0:00:00 0.013 0.244 0.006 0.018 0.018
6 ServerStack Linux 0:00:00 0.013 0.130 0.066 0.132 0.132
7 www.dinahosting.com Linux 0:00:00 0.013 0.267 0.081 0.163 0.163
8 Hyve Managed Hosting Linux 0:00:00 0.017 0.230 0.059 0.118 0.119
9 Pair Networks FreeBSD 0:00:00 0.017 0.239 0.070 0.142 0.142
10 Anexia Linux 0:00:00 0.017 0.197 0.085 0.181 0.181

See full table

Qube had the most reliable hosting company site in March, responding to all of Netcraft's requests. This continues Qube's strong performance from last year, where it placed in the top ten in eight months of 2015, and both January and February of 2016. Qube is based in London and offers a range of managed services, including private cloud hosting, from data centres in London, New York and Zurich.

In a very close second place, Netcetera also responded to every Netcraft request, but with a slightly longer average connection time. Netcetera owns and operates a carbon neutral data centre on the Isle of Man, and recently celebrated its 20th birthday, having been in the hosting business since 1996.

Datapipe takes third place in March, with two failed requests. Datapipe has an exceptionally consistent record for reliability, with its site maintaining 100% uptime over 10 years, and appearing in the top ten list on 42 occasions over the last 48 months.

Linux remains the most common choice of operating system amongst the most reliable hosting company sites, powering eight out of the top ten. Citrix Netscaler and FreeBSD also make an appearance, being employed by Kattare Internet Services and Pair Networks respectively.

Netcraft measures and makes available the response times of around forty leading hosting providers' sites. The performance measurements are made at fifteen minute intervals from separate points around the internet, and averages are calculated over the immediately preceding 24 hour period.

From a customer's point of view, the percentage of failed requests is more pertinent than outages on hosting companies' own sites, as this gives a pointer to reliability of routing, and this is why we choose to rank our table by fewest failed requests, rather than shortest periods of outage. In the event the number of failed requests are equal then sites are ranked by average connection times.

Information on the measurement process and current measurements is available.

HTTP Public Key Pinning: You’re doing it wrong!

HTTP Public Key Pinning (HPKP) is a security feature that can prevent fraudulently issued TLS certificates from being used to impersonate existing secure websites.

Our previous article detailed how this technology works, and looked at some of the sites that have dared to use this powerful but risky feature. Notably, very few sites are making use of HPKP: Only 0.09% of the certificates in Netcraft's March 2016 SSL Survey are served with HPKP headers, which equates to fewer than 4,100 certificates in total.

But more surprisingly, around a third of these sites are using the HPKP header incorrectly, which effectively disables HPKP. Consequently, the total number of certificates that are actually using HPKP is effectively less than 3,000.

Firefox's developer console reveals that this site has failed to include a backup pin, and so its HPKP policy is ignored by the browser.Failing to include a backup pin is the most common type of mistake made by sites that try to use HPKP.

Firefox's developer console reveals that this site has failed to include a backup pin, and so its HPKP policy is ignored by the browser.
Failing to include a backup pin is the most common type of mistake made by sites that try to use HPKP.

HPKP is the best way of protecting a site from being impersonated by mis-issued certificates, but it is easy for this protection to backfire with severe consequences. Fortunately, most misconfigurations simply mean that a site's HPKP policy will be ignored by browsers. The site's administrators might not realise it, but this situation is essentially the same as not using HPKP at all.

How can it go wrong?

Our previous article demonstrated a few high-profile websites that were using HPKP to varying degrees. However, plenty of other sites have bungled HPKP to the extent that it simply does not work.

Zero max-age

Every HPKP policy must specify a max-age directive, which suggests how long a browser should regard the website as a "Known Pinned Host". The most commonly used max-age value is 5184000 seconds (60 days). Nearly 1,200 servers use this value, while around 900 use 2592000 seconds (30 days).

But around 70 sites feature pointlessly short max-age values, such as 5 or 10 seconds. These durations are far too short to be effective, as a victim's browser would rapidly forget about these known pinned hosts.

Additionally, a few sites explicitly specify a max-age of zero along with their public key pins. These sites are therefore not protected by HPKP, and are in some cases needlessly sending this header to every client request. It is possible that they are desperately trying to remove a previously set HPKP policy, but this approach obviously cannot be relied upon to remove cached pins from browsers that do not visit the site in the meantime. These sites would therefore have to continue using a certificate chain that conforms to their previous HPKP policy, or run the risk of locking out a few stragglers.

One of the sites that sets a zero max-age is https://vodsmarket.com. Even if this max-age were to be increased, HPKP would still not be enabled because there is only one pinned public key:

Public-Key-Pins: pin-sha256="sbKjNAOqGTDfcyW1mBsy9IOtS2XS4AE+RJsm+LcR+mU="; max-age=0;

Another example can be seen on https://wondershift.biz, which pins two certificates' public keys. Again, even if the max-age were to be increased, this policy would still not take effect because there are no backup pins specified (both of the pinned keys appear in the site's certificate chain):

Public-Key-Pins: pin-sha256="L7mpy8M0VvQcWm7Yyx1LFK/+Ao280UZkz5U38Qk5G5g=";
    pin-sha256="EohwrK1N7rr3bRQphPj4j2cel+B2d0NNbM9PWHNDXpM=";
    includeSubDomains;
    max-age=0;
    report-uri="https://yahvehyireh.com/incoming/hpkp/index.php"

Wrong pin directives

Each pinned public key must be specified via a separate pin-sha256 directive, and each value must be a SHA256 hash; but more than 1% of servers that try to use HPKP fail to specify these pins correctly.

For example, the Department of Technology at Aichi University of Education exhibits the following header on https://www.auetech.aichi-edu.ac.jp:

Public-Key-Pins: YEnyhAxjrMAeVokI+23XQv1lzV3IBb3zs+BA2EUeLFI=";
    max-age=5184000;
    includeSubDomains

This header appears to include a single public key hash, but it omits the pin-sha256 directive entirely. No browser will make any sense of this attempted policy.

In another example, the Fast Forward Imaging Customer Interface at https://endor.ffwimaging.com does something very peculiar. It uses a pin-sha512 directive, which is not supported by the RFC – but in any case, the value it is set to is clearly not a SHA512 hash:

Public-Key-Pins: pin-sha512="base64+info1="; max-age=31536000; includeSubDomains

Some sites try to use SHA1 public key hashes, which are also unsupported:

Public-Key-Pins: pin-sha1='ewWxG0o6PsfOgu9uOCmZ0znd8h4='; max-age=2592000; includeSubdomains

This one uses pin-sha instead of pin-sha256:

Public-Key-Pins: pin-sha="xZ4wUjthUJ0YMBsdGg/bXHUjpEec5s+tHDNnNtdkwq8=";
    max-age=5184000; includeSubDomains

And this one refers to the algorithm "SHA245", which does not exist:

Public-Key-Pins: pin-sha245="pyCA+ftfVu/P+92tEhZWnVJ4BGO78XWwNhyynshV9C4=";
    max-age=31536000; includeSubDomains

The above example was most likely a typo, as is the following example, which specifies a ping-sha256 value:

Public-Key-Pins: ping-sha256="5C8kvU039KouVrl52D0eZSGf4Onjo4Khs8tmyTlV3nU=";
    max-age=2592000; includeSubDomains

These are careless mistakes, but it is notable that these types of mistake alone account for more than 1% of all certificates that set the Public-Key-Pins header. The net effect of these mistakes is that HPKP is not enabled on these sites.

Only one pinned public key

As we emphasised in our previous article, it is essential that a secure site should specify at least two public key pins when deploying HPKP. At least one of these should be a backup pin, so that the website can recover from losing control of its deployed certificate. If the website owner still possesses the private key for one of the backup certificates, the site can revert to using one of the other pinned public keys without any browsers refusing to connect.

But 25% of servers that use HPKP specify only one public key pin. This means that HPKP will not be enabled on the sites that use these certificates.

To prevent sites from inadvertently locking out all of their visitors, and to force the use of backup pins, browsers should only cache a site's pinned public keys if the Public-Key-Pins header contains two or more hashes. At least one of these must correspond to a certificate that is in the site's certificate chain, and at least one must be a backup pin (if a hash cannot be found in the certificate chain, then the browser will assume it is a backup pin without verifying its existence).

https://xcloud.zone is an example of a site that only sets one public key pin:

Public-Key-Pins: pin-sha256="DKvbzsurIZ5t5PvMaiEGfGF8dD2MA7aTUH9dbVtTN28=";
    max-age=2592000; includeSubDomains

This single pin corresponds to the subscriber certificate issued to xcloud.zone. Despite the 30-day max-age value, this lonely public key hash will never be cached by a browser. Consequently, HPKP is not enabled on this site, and the header might as well be missing entirely.

No pins at all

As well as the 1,000+ servers that only have one pinned public key, some HPKP headers neglect to specify any pins at all, and a few try to set values that are not actually hashes (which has the same effect as not setting any pins at all). For example, the Hide My Ass! forum at https://forum.hidemyass.com sets the following:

Public-Key-Pins: pin-sha256="<Subject Public Key Information (SPKI)>";
    max-age=2592000; includeSubDomains

The ProPublica SecureDrop site at https://securedrop.propublica.org also made a subtle mistake last month by forgetting to enclose its pinned public key hashes in double-quotes:

Public-Key-Pins: max-age=86400;
    pin-sha256=rhdxr9/utGWqudj8bNbG3sEcyMYn5wspiI5mZWkHE8A=
    pin-sha256=lT09gPUeQfbYrlxRtpsHrjDblj9Rpz+u7ajfCrg4qDM=

The HPKP RFC mandates that the Base64-encoded public key hashes must be quoted strings, so the above policy would not have worked. ProPublica has since fixed this problem, as well as adding a third pin to the header.

ProPublica is an independent newsroom that produces investigative journalism in the public interest. It provides a SecureDrop site to allow tips or documents to be submitted securely; however, until recently the HPKP policy on this site was ineffectual.

ProPublica is an independent newsroom that produces investigative journalism in the public interest. It provides a SecureDrop site to allow tips or documents to be submitted securely; however, until recently the HPKP policy on this site was ineffectual.

If companies that specialise in online privacy and secure anonymous filesharing are making these kinds of mistake on their own websites, it's not surprising that so many other websites are also getting it wrong.

At least two pins, but no backup pins

A valid HPKP policy must specify at least two pins, and at least one of these must be a backup pin. A browser will assume that a pin corresponds to a backup certificate if none of the certificates in the site's certificate chain correspond to that pin.

The Samba mailing list website fails to include any backup pins. Consequently, its HPKP policy is not enforced.

The Samba mailing list website fails to include any backup pins. Consequently, its HPKP policy is not enforced.

The Samba mailing lists site at https://lists.samba.org specifies two pinned public key hashes, but both of these appear in its certificate chain. Consequently, a browser will not apply this policy because there is no evidence of a backup pin. HPKP is effectively disabled on this site.

Incidentally, the Let's Encrypt Authority X1 cross-signed intermediate certificate has the most commonly pinned public key in our survey. More than 9% feature this in their set of pins, although it should never be pinned exclusively because Let's Encrypt is not guaranteed to always use their X1 certificate. Topically, just a few days ago, Let's Encrypt started to issue all certificates via its new Let's Encrypt Authority X3 intermediate certificate in order to be compatible with older Windows XP clients; but fortunately, the new X3 certificate uses the same keys as the X1 certificate, and so any site that had pinned the public key of the X1 certificate will continue to be accessible when it renews its subscriber certificate, without having to change its current HPKP policy.

The next most common pin belongs to the COMODO RSA Domain Validation Secure Server CA certificate. This pin is used by more than 6% of servers in our survey, all of which – despite the use of HPKP – could be vulnerable to man-in-the-middle attacks if Comodo were to be hacked again.

Pinning only the public keys of subscriber certificates would offer the best security against these kinds of attack, but it is fairly common to also pin the keys of root and intermediate certificates to reduce the risk of "bricking" a website in the event of a key loss. This approach is very common among Let's Encrypt customers, as the default letsencrypt client software generates a new key pair each time a certificate is renewed. If the public key of the subscriber certificate were to be pinned, the pinning would no longer be valid when it is renewed.

Setting HPKP policies over HTTP

Some sites set HPKP headers over unencrypted HTTP connections, which is also ineffectual. For example, the Internet Storm Center website at www.dshield.org sets the following header on its HTTP site:

Public-Key-Pins: pin-sha256="oBPvhtvElQwtqQAFCzmHX7iaOgvmPfYDRPEMP5zVMBQ=";
    pin-sha256="Ofki57ad70COg0ke3x80cbJ62Tt3c/f3skTimJdpnTw=";
    max-age=2592000; report-uri="https://isc.sans.org/badkey.html"

The Public Key Pinning Extension for HTTP RFC states that browsers must ignore HPKP headers that are received over non-secure transport, and so the above header has no effect other than to consume additional bandwidth.

2.2.2.  HTTP Request Type
  Pinned Hosts SHOULD NOT include the PKP header field in HTTP
  responses conveyed over non-secure transport.  UAs MUST ignore any
  PKP header received in an HTTP response conveyed over non-secure
  transport.

One very good reason for ignoring HPKP policies that are set over unencrypted connections is to prevent "hostile pinning" by man-in-the-middle attackers. If an attacker were to inject a set of pins that the site owner does not control—and if the browser were to blindly cache these values—he would be able to create a junk policy on behalf of that website. This would prevent clients from accessing the site for a long period, without the attacker having to maintain his position as a man-in-the-middle.

If a visitor instead browses to https://www.dshield.org (using HTTPS), an HSTS policy is applied which forces future requests to use HTTPS. The HTTPS site also sets an HPKP header which is then accepted and cached by compatible browsers. However, as the HTTP site does not automatically redirect to the HTTPS site, it is likely that many visitors will never benefit from these HSTS or HPKP polices, even though they are correctly implemented on the HTTPS site.

In another bizarre example, HPKP headers are set by the HTTP site at http://www.msvmgroup.com, even though there is no corresponding HTTPS website (it does accept connections on port 443, but does not present a subscriber certificate that is valid for this hostname).

Not quite got round to it yet...

A few sites that use the Public-Key-Pins header have not quite got around to implementing it yet, such as https://justamagic.ru, which sets the following value:

Public-Key-Pins: TODO

Using HPKP headers to broadcast skepticism

One security company's website – https://websec-test.com – uses the Public-Key-Pins header to express its own skepticisms over the usefulness of HPKP:

Public-Key-Pins: This is like the most useless header I have ever seen.
    Preventing MITM, c'mon, whoever can't trust his own network shouldn't
    enter sensitive data anywhere.

Violation reports that will never be received

The Public-Key-Pins header supports an optional report-uri directive. In the event of a pin validation failure, the user's browser should send a report to this address, in addition to blocking access to the site. These reports are obviously valuable, as they will usually be the first indication that something is wrong.

However, if the report-uri address uses HTTPS, and is also known pinned host, the browser must also carry out pinning checks on this address when the report is sent. This makes it foolish to specify a report-uri that uses the same hostname as the site that is using HPKP.

An example of this configuration blunder can be seen on https://yahvehyireh.com, which sets the following Public-Key-Pins header:

Public-Key-Pins: pin-sha256="y+PfuAS+Dx0OspfM9POCW/HRIqMqsa83jeXaOECu1Ns=";
    pin-sha256="klO23nT2ehFDXCfx3eHTDRESMz3asj1muO+4aIdjiuY=";
    pin-sha256="EohwrK1N7rr3bRQphPj4j2cel+B2d0NNbM9PWHNDXpM=";
    includeSubDomains; max-age=0;
     report-uri="https://yahvehyireh.com/incoming/hpkp/index.php"

This header instructs the browser to send pinning validation failure reports to https://yahvehyireh.com/incoming/hpkp/index.php. However, if there were to be a pinning validation failure on yahvehyireh.com, then the browser would be unable to send any reports because the report-uri itself would also fail the pinning checks by virtue of using the same hostname.

Incidentally, Chrome 46 introduced support for a newer header, Public-Key-Pins-Report-Only, which instructs the browser to perform identical pinning checks to those specified by the Public-Key-Pins header, but it will never block a request when no pinned keys are encountered; instead, the browser will send a report to a URL specified by a report-uri parameter, and the user will be allowed to continue browsing the site. This mechanism would make it safe for site administrators to test the deployment of HPKP on their sites, without inadvertently introducing a denial of service.

Summary

The proportion of secure servers that use HPKP headers is woefully low at only 0.09%, but to make matters worse, many of these few HPKP policies have been implemented incorrectly and do not work as intended.

Without delving into developer settings, browsers offer no visible indications that a site has an invalid HPKP policy, and so it is likely that many website administrators have no idea that their attempts at implementing HPKP have failed. Around a third of the sites that attempt to set an HPKP policy have got it wrong, and consequently behave as if there was no HPKP policy at all. Every response from these servers will include the unnecessary overhead of a header containing a policy that will ultimately be ignored by all browsers.

But there is still hope for the masses: A more viable alternative to HPKP might arise from an Internet-Draft entitled TLS Server Identity Pinning with Tickets. It proposes to extend TLS with opaque tickets, similar to those being used for TLS session resumption, as a way to pin a server's identity. This feature would allow a client to ensure that it is connecting to the right server, even in the presence of a fraudulently issued certificate, but has a significant advantage over HPKP in that no manual management actions would be required. If this draft comes to fruition, and is subsequently implemented by browsers and servers, this ticket-based approach to pinning could potentially see a greater uptake than HPKP has.

Netcraft offers a range of services that can be used to detect and defeat large-scale pharming attacks, and security testing services that identify man-in-the-middle vulnerabilities in web application and mobile apps. Contact security-sales@netcraft.com for more information.