In response to a media request on Facebook confirmed the fact of leakage. It was like this: back in 2019, someone took advantage of a vulnerability in the tool for finding friends, which itself raises doubts from the point of view of privacy. This feature uploaded the user’s phone book to the servers of the social network and invited him to add the people he found to his friends. As it turned out later, the tool made it possible to brute force through the entire array of phone numbers and upload data on a large number of users – approximately 20% of the total number of accounts on the social network.
In the same 2019, a similar problem found in Telegram: busting phone numbers helped to find out the user’s nickname, and through the database of mobile operators – to link the account in the messenger with a real person.
For obvious reasons, passwords did not leak from Facebook, but a lot of personal data got into the public domain: names, location, information about the employer, gender, date of registration. The base from 2019, apparently, was sold on the black market for some time, and in January of this year, a bot appeared on Telegram that sells data by phone number. Relatively few e-mail addresses associated with accounts have leaked: Troy Hunt added to the service database Haveibeenpwned only 2.5 million records.
The leak alone is unlikely to add new risks to the individual user. For a long time, a simple rule has been applied to social networks: if you transfer some data to them, consider it public, even if some privacy settings are applied.
This story brings up the topic of phone number security again – a key way of identifying a person. Changing a number is even more difficult than a postal address, its loss is fraught with direct financial damage, and there are many ways to intercept data transmitted via SMS. It is easy to imagine an attack scheme in which cybercriminals determine a user number after leaking such databases, and then, through social engineering or direct substitution of a SIM card, they gain access to a bank account. It is clear what to do with this, although these actions cause additional difficulties. For example, switch to other means of two-factor authentication or use different numbers for registering on public services and for accessing banking services. As usual, punctures from third-party services that freely handle user data bring problems to the users themselves.
What else happened
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Lockers, a computer attack from at least a decade ago, have become less common with the development of ransomware Trojans. In fresh research Kaspersky Lab experts remind that malicious programs that require a ransom for unlocking a computer have not gone anywhere. This article discusses blockers that work strictly in a web browser.
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