A worm that spreads through low security networks, memory sticks, and PCs without the latest security updates is posing a growing threat to users. The malicious program, known as Conficker, Downadup, or Kido was first discovered in October 2008. Although Microsoft released a patch, it has gone on to infect 3.5m machines. Experts warn this figure could be far higher and say users should have up-to-date anti-virus software and install Microsoft's MS08-067 patch.