Free internet-calling service Skype is being used by hackers to distribute a ‘worm’ that infects users Windows PCs.
On clicking an instant message saying “lol is this your new profile pic?” users are unwittingly downloading a file containing a Trojan horse malware file.
This opens a backdoor allowing hackers to hijack infected PCs and recruit them into a “botnet army”.
Users can be locked out of their machines and held to ransom, according to reports.
Skype said in a statement that they ‘are aware of this malicious activity and are working quickly to mitigate its impact.’
“We strongly recommend upgrading to the newest Skype version and applying updated security features on your computer,” the firm said in a statement.
“Additionally, following links – even when from your contacts – that look strange or are unexpected is not advisable,” it added.