Kaspersky Labs has hit upon a novel way of keeping its users’ computers free of viruses and malware, simply by preventing them from being able to connect to the web at all.

Millions of Kaspersky antivirus users were left bemused at being unable to get online following a buggy update issued by the security firm this week, which caused computers running Windows XP to disconnect from the internet. After some confusion, dozens of users quickly worked out what the cause of the problem must be, taking to the official Kaspersky forums to express their annoyance at the vendor and its lack of communication.

Sometime after the disaster began, a number of IT admins posted on the forum to say that they’d manage to restore connectivity by disabling the anti-virus component or shutting down certain ports, but these were only temporary fixes.

Later, Kaspersky finally stepped up to acknowledge that it was the cause of the blackout, announcing that it had issued a fix to the broken update. Unfortunately, because most people had been forced offline, they were unable to auto-install the fix from the net, and instead had to perform several tricky tasks beforehand:

To get XP users Internet connectivity (temporarily), please disable the Web AV component of your protection policy for your managed computers. After doing so;

In Security Center (or Admin Kit):

1) Go to the Repositories section >> (Right click) Updates >> All Tasks >> Clear updates repository.

2) Go to the Repositories section >> (Right click) Updates >> Download Updates

After taking this step, please run your group update task for Managed Computers. After the update has been pushed to your workstations, please re-enable your Web AV component in your protection policy. This should resolve the issue.

Unfortunately, some users found Kaspersky’s ‘advice’ rather hard to follow, with dozens of users complaining on Wednesday that they still hadn’t managed to fix the problem, despite having engaged Kaspersky staff in online chats. Meanwhile, others complained that the fix for the update was incredibly slows to download, taking up to 24 hours in some cases. Unsurprisingly, several users had harsh words for the security firm:

“I just wanted to thank the good folks at Kaspersky for insuring that my hospital has either crippled or no AntiVirus,” said one user. “The workaround of disabling A/V is outright stupid.”

Kaspersky was also criticized for failing to respond to the legion of complaints posted on its forum:

“I can’t believe that Kaspersky is not responding to any of these forums,” said one frustrated users. “That is horrible. One more reason why we will be switching to a different antivirus vendor after the contract is done.”

Kaspersky later issued a statement apologizing for the inconvenience it had caused its customers, adding that it had taken action to ensure this kind of incident does not occur in the future.

Surprisingly, considering that one would think internet security companies would have a better handle on things than everyone else, bad antivirus updates are not all that uncommon. Pretty much every antivirus firm has goofed up in the past, although most are minor. Others are not so fortunate however, such as when Avira’s update last year caused the software start deleting critical system files that prevented Windows from booting up.