A list of credentials being posted to the dark web as part of a much larger compilation include email addresses and their corresponding passwords.

Criminals are attempting to repackage data from past data breaches as a method of monetising old credentials, highlighting the importance of separating passwords and keeping work credentials limited to official use.

During analysis of the credentials, it became clear that all of the credentials listed had been previously breached multiple times with the most recent being 2019.

The credentials will be less useful to threat actors where strong password management policies are in place.

One of the main sources of the identified list was a breach dubbed Collection#1. This was discovered in 2019 when a list of 773 million unique email addresses were found being traded around dark web forums for credential stuffing attacks.

A credential stuffing attack occurs when an email address and password combination are compromised on one site, and a threat actor attempts to 'stuff' the combination into other sites to gain access.

Two of the oldest sources were from a data breach in MySpace in 2008 which exposed around 360 million user accounts, appearing for sale in 2016.

The second was from LinkedIn in 2016 when over 164 million email addresses and their passwords were exposed, this data did not appear for sale until 2020.

One of the reasons that threat actors will wait a number of years to post data for sale is that using the data can be more profitable than selling the data. Using the exposed credentials to gain access to more valuable data is typically a priority.

This latest posting is an example of how threat actors will compile past data breaches and repackage them in an attempt to monetise old credential combinations.

Other reading

• Read previous blogs on password safety

Reporting

Report all Fraud and Cybercrime to Action Fraud by calling 0300 123 2040 or online. Forward suspicious emails to report@phishing.gov.uk. Report SMS scams by forwarding the original message to 7726 (spells SPAM on the keypad).