Safe Browsing is a core security feature of Google’s Chrome web browser. The technology is also used by other browsers, often indirectly to improve privacy.
Google revealed in a new post on the Chromium blog that it has optimized Safe Browsing checks in the Chrome web browser.
The changes bring a performance boost to Safe Browsing checks thanks to the use of asynchronous checks. Some checks are also reduced to reduce their impact on the page loading time.
Safe Browsing: Asynchronous checks
Safe Browsing checks block pages from loading. This is a security precaution to ensure that malicious content is blocked before it can be loaded by the Chrome browser.
This is usually not a problem for local checks according to Google. Checks on Internet websites, on the other hand, add latency to the loading of the page.
Google Chrome 122 enables asynchronous Safe Browsing checks. This allows sites to load content during checks. Google says that this will reduce page load times in Chrome and improve the overall user experience.
Chrome continues to show a warning page if Safe Browsing determines that a page or one of its resources is problematic.
There is also potential for improving new artificial intelligence and machine learning algorithms “to detect and block more phishing and social engineering attacks” according to Google. These experiments could affect the page loading time further in the past.
Risks associated with the change
Since pages may load while Safe Browsing checks take place, there is a chance of attacks.
Google says that it has evaluated two common attack types and concluded that sufficient mitigations are in place:
- Phishing and social engineering attacks — Phishing sites may load while checks are still ongoing. Google believes that it is unlikely that users will have the time to interact with the site in a way that would impact security. Selecting a password field and typing the password, for instance, should take longer than the Safe Browsing check.
- Browser exploits — Chrome has a local list of sites that attack using browser exploits. Checks continue to be made asynchronously and Google recommends keeping Chrome up to date to block most attacks from being effective.
Sub-resource and PDF checks
Two additional checks are listed by Google that are impacted by the optimizations.
- Sub-resource checks — attacks using sub-resources are declining, according to Google. New protections, including intelligence gathering, threat detection, and Safe Browsing APIs, protect users in real-time without specifically needing to check sub-resources. As a consequence, Google Chrome will no “longer check the URLs of sub-resources with Safe Browsing”.
- PDF download checks — Google reduced the frequency of PDF download checks. PDF documents were used for attacks in the past, but widespread attacks are rare thanks to improvements to Chrome’s PDF viewer. Google notes that most PDF files use links for attacks. These link may open in Chrome, which gives Safe Browsing a chance to block the attack.
Closing Words
Google benefits from the reduction in changes. PDF checks alone reduce Safe Browsing checks “billions of times” each week. The removal of checks may push certain forms of attacks again. Sub-resource attacks may see a revival as malicious actors find new ways to exploit the change.
Chrome users may check the browser’s Safe Browsing preferences under chrome://settings/security. There they find the two main options — standard and enhanced protection — as well as an option to turn off the security feature entirely.
