One in three technology workers have admitted to using special IT privileges to take a peek at confidential information, security experts have warned.

While you sit at your desk working away, little do you realise that a large number of IT work colleagues are apparently snooping through company systems, burrowing into confidential information such as private files, wage data, personal emails, and HR background, just by using the special administrative passwords that give them anonymous access to virtually any system.

The alleged scandal has been uncovered by Cyber-Ark Software, specialists in digital vaulting systems for securing administrative passwords.

Alarmingly, its survey also found that more than one-third of IT professionals admitted they could still access their company's network once they'd left their current job, with no one to stop them.

More than 200 IT professionals took part in the survey, with many revealing that although it wasn't corporate policy to allow IT workers to access systems after termination, still over one-quarter of respondents knew of another IT staff member who still had access to sensitive networks even though they'd left the company long ago. The Cyber-Ark experts also discovered that half of people still keep their passwords on a 'Post-It' note, in spite of all the education and reminders to do differently.

But surprisingly, that 50 per cent number now applies to IT professionals as well.

More than half of respondents admitted to using Post-It notes to store administrative passwords, the super-powerful codes pre-built into every system such the administrator ID on your local workstation.

As one IT administrator explained: "Sure, it's easy for an employee to update the personal password to their laptop, but to change the administrator password on that same machine? It would take days for IT to do them all by hand. In the end, we just pick one password for all the systems and write it down."

And where do they write it? A Post-It note. One-fifth of all organisations also admitted that they rarely changed their administrative passwords with seven per cent saying they never change administrative passwords.

This may explain why one-third of all people questioned would still have access to their network even if they'd left the company.

Eight per cent of IT professionals revealed that the manufacturer's default admin password on critical systems had never been changed, which remains the most common way for hackers to break into corporate networks.

Gary McKinnon - who has been named as the "most profligate military hacker of all time" and is still waiting to be extradited to the US for gaining entry to 90 computers at the US Department of Defense by scanning US military computer systems for blank administrator accounts - said: "The easiest way to infiltrate a company's network is to look for administrative passwords which are left blank, still have the manufacturer's default password or just use obvious names.

"Once you find these, which are unbelievably simple and common to find, you're into the system and have the highest level of authority - bingo, you've got control of the company's system."

The survey also showed that the majority of companies mismanage the storage of administrative passwords by keeping them in unsecured locations, hence not controlling access to these critical codes.

Some 57 per cent of companies store their administrative passwords manually, 18 per cent store them in an excel spreadsheet, which are notoriously insecure and easy to access, and 82 per cent of IT professionals store them in their heads - hindering security efforts, business continuity, as well as the auditing, controlling and managing of passwords.

Cyber-Ark warns that in the event that the keeper of these critical administrative passwords is unavailable or loses the location of the passwords, it can cause massive disruption and hours of lost productivity.

Fifteen per cent of companies interviewed had experienced insider sabotage, which is not surprising considering that over one-third of IT staff report using administrative passwords to snoop around corporate systems.

Even worse, such snooping can turn ugly when IT workers feel disgruntled, aggrieved and especially after they've been fired.

According to a recent study by Carnegie Mellon University, the most common insider attack is by a disgruntled IT employee using anonymous access from a privileged account.

Calum Macleod, European director for Cyber-Ark said: "It's surprising to find out how rife snooping is in the workplace.

"Gone are the days when you had to break into the filing cabinet in the personnel department to get at vital and highly confidential information.

"Now all you need to have is the administrative password and you can snoop around most places, and it appears that is exactly what's happening.

"Companies need to wake up to the fact that if they don't introduce layers of security, tighten up who has access to vital information, and manage and control privileged passwords, then snooping, sabotage and hacking will continue to be rife.