How Google keeps your data safe

From hacking and phishing to malware, cybercriminals employ a variety of methods to hijack user accounts. Google's Stephan Micklitz and Tadek Pietraszek make sure that they don’t succeed.

Mr. Pietraszek, you and your team are responsible for keeping user accounts secure. How do you prevent hackers from gaining access?

Tadek Pietraszek, Principal Software Engineer for user account security: First of all, it’s important that we’re able to detect the initial attack. We use more than a hundred variables to identify suspicious activity. Suppose you live in Germany, very rarely travel abroad and someone tries to access your account from another country – that sets off alarm bells.

Stephan Micklitz, Director of Engineering on Google’s Privacy and Security team: That’s why we sometimes ask you to confirm the telephone number that you’ve given us, or other information that only you as the account holder would know.

How often do these sorts of attacks occur?

Pietraszek: Hundreds of thousands of cyberattacks are launched every day. Our biggest problem is that the Internet contains countless lists of usernames and passwords stolen from hacked websites. As a number of our users have the same password for different accounts, these lists also include Google Account login data.

Do these lists pose the biggest security threat?

Pietraszek: Yes, absolutely. That and the classic phishing attacks. Almost everyone has received emails from criminals trying to obtain account passwords. Naturally, we do our part to make sure that they don’t succeed. If we think an email destined for your Gmail inbox looks suspicious, we can mark it with a warning so that you can take a closer look or we can automatically filter it out. Our Chrome Browser also sends alerts when you try to visit a site that we know to be a phishing website.

Micklitz: There are two basic types of phishing. The mass emails, which perpetrators use to collect as much login data as possible, and what’s known as 'spear phishing', in which they target a specific person’s account. These can be quite sophisticated operations lasting several months, during which time the perpetrator examines the victim’s life in detail and launches a very targeted attack.

Could you tell us about a major cyberattack and how you reacted to that?

Pietraszek: One of these attacks occured in early 2017. Hackers had created a malicious program to gain access to the victims’ Google Accounts and send fake emails to the users’ contacts. In these emails, recipients were asked to grant access to a fake Google document. Those who did so involuntarily granted access to the malware and automatically sent the same fake emails to their own contacts. The virus spread rapidly. We have contingency plans for situations like these.

Micklitz: In this particular case, for example, we blocked the distribution of these emails in Gmail, revoked the access granted to the program and secured the accounts. Of course, we’ve also added systematic safeguards to make similar attacks more difficult in the future. Google Accounts are constantly under attack, and our automated systems offer the most effective protection. This depends, of course, on our being able to reach our users via means other than their Google Account; i.e. a second email address or a mobile phone number.

Photographs: Conny Mirbach