Instant messaging attacks leapt 162 percent in April according to security firm Akonix. The company tracked 21 new malicious code attacks over the month.

The jump accompanies a boom in take-up of enterprise unified communications systems (UC) over the past few months, a fact that is unlikely to be a mere coincidence, Akonix said.

UC systems are designed to bring together all a company's communications systems onto a common Internet protocol (IP) infrastructure, and often include an IM service.

Analysts Butler Group reassured enterprises in a report earlier this week that UC does not open up any new means of attack, but Akonix said the recent spike in IM attacks indicates just the reverse.

"Enterprises need to realise that implementing new communication and collaboration tools increases the risk of attack as each new application becomes a new vector for infection," said Akonix vice president of marketing Don Montgomery, in a statement.

Among the new IM worms were ArcServe, IMspread and QVOD, according to Akonix. The most common were IRCBot and Tiotua, with three variants each.

Attacks on P2P networks such as Kazaa and eDonkey increased 13 percent compared to March, with 18 attacks in total, Akonix said.

MessageLabs predicted a spike in attacks on IM systems for 2007, something it admitted in November had not occurred. The same firm predicted criminal attention to IM networks would arrive during 2008.