The tool is intended for defensive purposes, but could also be used to facilitate password attacks
A security researcher has published a command-line tool that checks whether a password has been reused across a number of sites, in the wake of several large data breaches involving popular social media services.
The breaches, which exposed the passwords of more than 640 million accounts, led to a number of high-profile hacks, including one involving Facebook chief executive Mark Zuckerberg.
The tool, called Shard, is intended to help users ensure the password they use will not leave them exposed to attackers, said its developer Philip O’Keefe, an IT security researcher at Netsuite.
However, it could also be misused to automate the process of exploiting leaked passwords to hack accounts on sites where the same password was reused, industry observers said.
Shard checks passwords on Facebook, LinkedIn, Reddit, Twitter and Instagram, but it is easy to add more sites, O’Keefe said.
He said the tool found that a randomly generated password he had used on several websites was one of the 177 million LinkedIn passwords published online in May, leading him to begin using a password manager.
He said it would be difficult for sites to block traffic from the tool, since it is designed to imitate ordinary user behaviour.
Security experts recommend the use of a password manager, making it possible to use different complex passwords across multiple services, in order to guard against increasingly frequent password attacks.
Two-factor authentication can also be used with most online services, making them less vulnerable to a hack that only involves a password.
It is likely that hackers already use automated password tools similar to Shard, but the new tool is particularly easy to use, a factor that has increased the danger of hacking in other areas.
A recent study by IBM and KPMG concluded that businesses are in the midst of an “arms race” with increasingly sophisticated computer criminals who are often well-organised in groups that resemble corporations.
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