The release contained only the passwords of the users and not the associated email addresses, making the hack only slightly less worrying. The passwords were also hashed, seemingly with the SHA1 algorithm, but unsalted. The salting factor is generally what makes hashing more secure and without, many of the passwords were easily reversed back into plain text. The failure to properly use a salt during the hashing phase is deemed to be a major failure in basic password security.
It was the analysis of the hashed passwords that initially led to the news that the leaked passwords were in fact from the LinkedIn site. Several of the passwords used the words 'linkedin' or 'LinkedIn' within them. The hashed passwords were then posted onto a Russian on line forum where users were asked for help in the reverse hashing process. Whilst several of the passwords have allegedly been reversed into plain text, many argue that out of the 6.5 million, only a small percentage of the easiest passwords will be converted to plaintext.
Whilst the true risk could be relatively small, LinkedIn's response has been swift. An acknowledgement arrived saying data had been released and the accounts their believed to be impacted have had a password reset requirement flag set. The questions still arise: How did the hackers get access to the hash data? How long had they had access for? More importantly, if the entry method is still unknown, do LinkedIn know that they no longer have access?
A prompt to quickly reset all 6.5 million passwords, is futile if the hackers also have access to the new hash data... Another area of concern is that LinkedIn also offers a premium service that would require the credit card details to be used to pay for the subscription. Was this data compromised?
The main remediation steps seem to have been to forcefully reset the accounts of those known to be effected, whilst a blog entry by Linked In Director Vincente Silveira advises for everyone to reset their password on Linked In regularly and to not use the same password for multiple sites. The password, of course should be as long and complex as possible (whilst still being able to remember it..)
As many on line sites become more popular, it is inevitable a hacking incident or a breach will occur simply due to the complexity of the sites involved (huge data centres, many members of staff, contractors, integration points & 3rd party libraries) as well as the huge driver of being a hacker against large and well known brands.
Whilst many will argue that poor protection of the assets is to be blame, individuals will have a duty as well, for making sure passwords are secure and kept safe. Ultimately though, it's up to the service provider to keep information assets secure and develop trust between themselves and their community. Incidents like this, although potentially more newsworthy than truly impacting, serve to destroy that trust and image.