We are hopeful that no one will encounter this error, since public CAs must stop issuing SHA-1 certificates in 2016 per the Baseline Requirements for SSL.
In addition, a later version of Chrome in 2016 may extend these criteria in order to help guard against SHA-1 collision attacks on older devices, by displaying a certificate error for sites with certificate chains that:
contain an intermediate or leaf certificate signed with a SHA-1-based signature
contain an intermediate or leaf certificate issued on or after January 1, 2016
chain to a public CA
(Note that the first two criteria can match different certificates.)
Note that sites using new SHA-1 certificates that chain to local trust anchors (rather than public CAs) will continue to work without a certificate error. However, they will still be subject to the UI downgrade specified in our original announcement.
Step 2: Blocking all SHA-1 certificates
Starting January 1, 2017 at the latest, Chrome will completely stop supporting SHA-1 certificates. At this point, sites that have a SHA-1-based signature as part of the certificate chain (not including the self-signature on the root certificate) will trigger a fatal network error. This includes certificate chains that end in a local trust anchor as well as those that end at a public CA.
In line with Microsoft Edge and Mozilla Firefox, the target date for this step is January 1, 2017, but we are considering moving it earlier to July 1, 2016 in light of ongoing research. We therefore urge sites to replace any remaining SHA-1 certificates as soon as possible.
Note that Chrome uses the certificate trust settings of the host OS where possible, and that an update such as Microsoft’s planned change will cause a fatal network error in Chrome, regardless of Chrome’s intended target date.
Keeping your site safe and compatible
As individual TLS features are found to be too weak, browsers need to drop support for those features to keep users safe. Unfortunately, SHA-1 certificates are not the only feature that browsers will remove in the near future.
As we announced on our security-dev mailing list, Chrome 48 will also stop supporting RC4 cipher suites for TLS connections. This aligns with timelines for Microsoft Edge and Mozilla Firefox.
For security and interoperability in the face of upcoming browser changes, site operators should ensure that their servers use SHA-2 certificates, support non-RC4 cipher suites, and follow TLS best practices. In particular, we recommend that most sites support TLS 1.2 and prioritize the ECDHE_RSA_WITH_AES_128_GCM cipher suite. We also encourage site operators to use tools like the SSL Labs server test and Mozilla's SSL Configuration Generator.
Although our systems prefer the HTTPS version by default, you can also make this clearer for other search engines by redirecting your HTTP site to your HTTPS version and by implementing the HSTS header on your server.
We’re excited about taking another step forward in making the web more secure. By showing users HTTPS pages in our search results, we’re hoping to decrease the risk for users to browse a website over an insecure connection and making themselves vulnerable to content injection attacks. As usual, if you have any questions or comments, please let us know in the comments section below or in our webmaster help forums.
Next, we had to better understand how UwS is being disseminated.
This varies quite a bit, but time and again, deception is at the heart of these tactics. Common UwS distribution tactics include: unwanted ad injection, misleading ads such as “trick-to-click”, ads disguised as ‘download’ or ‘play’ buttons, bad software downloader practices, misleading or missing disclosures about what the software does, hijacked browser default settings, annoying system pop-up messages, and more.
Here are a few specific examples:
Deceptive ads leading to UwS downloads
Ads from unwanted ads injector taking over a New York Times page and sending the user to phone scams
Unwanted ad injector inserts ads on the Google search results page
New tab page is overridden by UwS
UwS hijacks Chrome navigations and directs users to a scam tech support website
One year of progress
Because UwS touches so many different parts of people’s online experiences, we’ve worked to fight it on many different fronts. Weaving UwS detection into Safe Browsing has been critical to this work, and we’ve pursued other efforts as well—here’s an overview:
We now include UwS in Safe Browsing and its API, enabling people who use Chrome and other browsers to see warnings before they go to sites that contain UwS. The red warning below appears in Chrome.
We launched the Chrome Cleanup Tool, a one-shot UwS removal tool that has helped clean more than 40 million devices. We shed more light on a common symptom of UwS—unwanted ad injectors. We outlined how they make money and launched a new filter in DoubleClick Bid Manager that removes impressions generated by unwanted ad injectors before bids are made.
We started using UwS as a signal in search to reduce the likelihood that sites with UwS would appear in search results.
We started disabling Google ads that lead to sites with UwS downloads.
It’s still early, but these changes have already begun to move the needle.
UwS-related Chrome user complaints have fallen. Last year, before we rolled-out our new policies, these were 40% of total complaints and now they’re 20%.
We’re now showing more than 5 million Safe Browsing warnings per day on Chrome related to UwS to ensure users are aware of a site’s potential risks.
We helped more than 14 million users remove over 190 deceptive Chrome extensions from their devices.
We reduced the number of UwS warnings that users see via AdWords by 95%, compared to last year. Even prior to last year, less than 1% of UwS downloads were due to AdWords.
However, there is still a long way to go. 20% of all feedback from Chrome users is related to UwS and we believe 1 in 10 Chrome users have hijacked settings or unwanted ad injectors on their machines. We expect users of other browsers continue to suffer from similar issues; there is lots of work still to be done.
Looking ahead: broad industry participation is essential
Given the complexity of the UwS ecosystem, the involvement of players across the industry is key to making meaningful progress in this fight. This chain is only as strong as its weakest links: everyone must work to develop and enforce strict, clear policies related to major sources of UwS.
If we’re able, as an industry, to enforce these policies, then everyone will be able to provide better experiences for their users. With this in mind, we’re very pleased to see that the FTC recently warned consumers about UwS and characterizes UwS as a form of malware. This is an important step toward uniting the online community and focusing good actors on the common goal of eliminating UwS.
We’re still in the earliest stages of the fight against UwS, but we’re moving in the right direction. We’ll continue our efforts to protect users from UwS and work across the industry to eliminate these bad practices.
The new Authenticator also comes with a developer preview of support for NFC Security Key, based on the FIDO Universal 2nd Factor (U2F) protocol via NFC. Play Store will prompt for the NFC permission before you install this version of Authenticator.
Developers who want to learn more about U2F can refer to FIDO's specifications. Additionally, you can try it out at https://u2fdemo.appspot.com. Note that you'll need an Android device running the latest versions of Google Chrome and Authenticator and also a Security Key with NFC support.
Social engineering—and phishing in particular—requires different protection; we need to keep an up-to-date list of bad sites on the device to make sure we can warn people before they browse into a trap. Providing this protection on a mobile device is much more difficult than on a desktop system, in no small part because we have to make sure that list doesn’t get stale, yet:
Mobile data costs money for most users around the world. Data size matters a lot.
Mobile data speeds are slower than Wi-Fi in much of the world. Data size matters a lot.
Cellular connectivity quality is much more uneven, so getting the right data to the device quickly is critically important. Data size matters a lot.
Maximum Protection Per Bit
Bytes are big: our mantra is that every single bit that Safe Browsing sends a mobile device must improve protection. Network bandwidth and battery are the scarcest resources on a mobile device, so we had to carefully rethink how to best protect mobile users. Some social engineering attacks only happen in certain parts of the world, so we only send information that protects devices in the geographic regions they’re in.
We also make sure that we send information about the riskiest sites first: if we can only get a very short update through, as is often the case on lower-speed networks in emerging economies, the update really has to count. We also worked with Google’s compression team to make the little data that we do send as small as possible.
Together with the Android Security team, we made the software on the device extra stingy with memory and processor use, and careful about minimizing network traffic. All of these details matter to us; we must not waste our users’ data plans, or a single moment of their battery life.
More Mobile
We hunt badness on the Internet so that you don’t discover it the hard way, and our protection should never be an undue burden on your networking costs or your device’s battery. As more of the world relies on the mobile web, we want to make sure you’re as safe as can be, as efficiently as possible.
