You expect Trojans to show us technical innovation and maliciousness, not theological mentoring.

That was until the Yusufali-A Trojan (so named by security vendor Sophos), picked up in recent days by anti-virus companies. Once it has infected a user’s PC, the malware monitors subsequent web surfing until it notices any one of a number of English nouns.

If an offending word is detected in a visited site, the following Koranic message is displayed in English and Arabic.

“Yusufali: Know, therefore, that there is no god but Allah, and ask forgiveness for they fault, and for the men and women who believe: for Allah knows how ye move about and how ye dwell in your homes".

Anyone continuing to view the site, is then presented with a further message, and the option to shut down, log off or restart their PC. Any one of these buttons is actually a script to shut down the PC.

No matter that non-pornographic websites will fall foul of it as much as pornographic ones, this has to be the first Trojan that claims to be infecting users for a moral rather than profit-making purpose.

Whether or not it was written as a prank (and there have been plenty of viruses with such an outlook), this still gets you thinking: why not infect PCs for political purposes? Why should profit or marketing messages be the only ones we ever encounter? All in all, it’s amazing this doesn’t happen more regularly given that politics has become one of the Internet’s growth areas.

According to Sophos, it is unlikely that anyone will come across Yusufali-a Trojan because it is not easy to catch. It is also very easy to detect, anathema for any Trojan with designs on making mischief, or worse.

Information-stealing Trojans, by contrast, do the opposite because stealth is a necessary property of their design. Eventually someone will combine stealthiness – which aids spread – with in-your-face tendentiousness. There’s no end to the Internet’s hidden powers.