A bot's daily routine
"What does a system infected with the Waledac bot actually do all day long?" ESET's virus specialists asked themselves that question and to find the answer analysed the network traffic on a deliberately infected lab system. The answer isn't really a surprise: "mainly sending spam!" The bot in the ESET lab did so quite regularly, averaging about 6,500 emails an hour, or two per second.
Theoretically, that would give a daily output of 150,000 emails, but observations showed that the bot herders seem to give their little lambs a rest from time to time – probably depending on their orders situation. If a comparatively small botnet, with say 20,000 infected systems, were to unleash its full force, it could send three billion spam emails every day.
ESET's observations indicate that users who have no virus scanner usually don't realize their systems are infected. After all, two emails per second shouldn't put a normal PC off its stroke, so normal operation won't be disturbed with lengthy program loading times, drop-outs or other problems.
But ESET thinks otherwise, saying that the numbers alone should make users realize why their systems run so slowly when infected. Everyone does at least agree that, regardless of whether operation is impaired, it's important to keep systems free from viruses. Hints on protection against viruses and worms can be found in the The H Security Internet Toolkit.