Three new MyDoom variants have been found in the wild that contain not only malicious code but a plea for a job.

MyDoom U, V and W attempt to download a Trojan called Surila onto users' computers, which would allow hackers to take remote control and use the PC for spamming or distributed denial of service attacks.

And embedded in the virus code is the text: 'We searching 4 work in AV industry.'

But Graham Cluley, senior technology consultant at security company Sophos, said in a statement that this was the last way to land such a position.

"It's very simple: if you write a virus, we will never ever employ you," he said.

"Not only is it unethical to write malicious code, but it raises issues as to whether you could ever be trusted to develop the software which protects millions of users around the world from attack every day."

Antivirus developers have to ensure that their software works reliably, detecting over 90,000 viruses on a wide variety of operating systems and network configurations without causing problems, explained Cluley.

"Virus writers don't care if their code crashes or causes incompatibilities. You don't have to be a genius to write a virus," he said.

Antivirus companies also maintain that the skill sets involved in writing a virus and blocking one are very different.

Many antivirus companies perform background checks on employees working on such sensitive technology.

The latest MyDoom variants spread via email and require the user to click on an attachment to start the malicious code.

Infected emails come with a variety of basic social engineering techniques, including identifying the attachment as a virus report.