Over a million leaked and hacked credentials from the UK’s top law firms have been found on the Dark Web, leaving the firms vulnerable to phishing scams, and the possibility of significant data theft. The figures represent an average of 2,000 email addresses per company, with the largest firm having just over 30,000 email addresses on the Dark Web.

The email addresses, including nearly 80,000 from the legal industry’s Magic Circle, have been found by cybersecurity specialist RepKnighta s part of a campaign to raise awareness of the huge number of leaked and hacked credentials circulating on the Dark Web.

Almost all of the credentials were from third-party breaches, where a corporate email address had been used on a site like LinkedIn or Dropbox, and that site was subsequently compromised.  Worryingly, 80% of these email addresses featured in breaches which also contained passwords – often in plaintext.  Cybercriminals could potentially use these password to gain access to other private data, like employees’ online banking or social media, via ‘credential stuffing’ or spear phishing attacks, because more than 80% of people tend to re-use their password.

Using RepKnight’s Dark Web monitoring tool BreachAlert, RepKnight was able to uncover each of the exposed email domains across Dark Web, bin, dump and data breach sites, which feature almost 5 billion stolen, leaked or hacked credentials. Even where passwords aren’t present, each of these exposed email addresses represents a potential attack on a company’s network for criminals via phishing or other scams.

Patrick Martin, cybersecurity analyst at RepKnight said: “The truth is that no company in the world is safe from the threat of the Dark Web. The top 500 law firms RepKnight analysed almost certainly haven’t done anything wrong cybersecurity-wise, but all it takes for a breach to occur nowadays is for a single employee to accidentally fall for a phishing email or send sensitive data via email accidentally to the wrong person. It’s almost impossible to prevent.

“The data we found represents the easiest data to find– we just searched on the corporate email domain.  A far bigger issue for law firms is data breaches of highly sensitive information about client cases, customer contact information, or employee personal info such as home addresses, medical record and HR files.  That’s why – in addition to securing their networks – every firm should be deploying a Dark Web monitoring solution, so they can get alerted to leaks and breaches immediately.”

The research by RepKnight sheds light on the importance of breach detection as well as prevention. On average, European organisations take around 450 days to spot a security breach, which means that cybercriminals have a huge amount of time to access a corporate network, steal sensitive data, and leave before the organisation even realises they’ve been there.