Bagle shoots ahead of Rustock in spam-pumping triumph

The Bagle botnet has replaced Rustock as the single biggest source of email spam since the start of January.

The miscreants behind Rustock took a break from sending out pharmaceutical spam over the festive season before returning earlier this month. Since its return on 10 January, Rustock made up for lost time and sent 17.5 per cent of all spam blocked by MessageLabs this month. Bagle, however, has kept its nose out front with the distribution of one in five spam messages polluting the interwebs.

Rustock alone was responsible for 47.5 percent of all spam, approximately 44.1 billion junk mail messages every day, at its peak. But now the global nuisance has been beaten by Bagle, something of a comeback kid in the spam distribution scene.

"Bagle has been around before, but was not very active in 2010," Paul Wood, MessageLabs Intelligence Senior Analyst at Symantec explained. "It was in the top three in 2009 and sends only pharma spam."

Spam accounted for 78.6 percent of all email traffic in the first three weeks of 2011, the lowest rate since March 2009. By comparison, 83.9 per cent of all email traffic was spam in January 2010.

A temporary respite from the spam-sending activities of three botnets – Rustock, Lethic and Xarvester – along with upheavals among pharmaceutical spam-sending gangs saw junk mail volumes halved over two weeks between 25 December and early January.

Spam volumes dropped from 80.2 billion spam emails per day to 33.5 billion spam emails each day during this period, when Rustock switched to click fraud scams. The spam deluge respite was short-lived and is sadly unlikely to be repeated, Wood explains.

"The closure of spam affiliate, Spamit, was partially responsible for the disruption to spam output. However, there are likely other factors at work, such as consolidation and restructuring of pharmaceutical spam operations which has led to instability in the market likely to be exploited as a business opportunity by other spam gangs.

"We expect to see more pharmaceutical spam in 2011 as new pharmaceutical spam brands emerge and botnets compete for their business."

More details on the latest in the spam-sending scene can be found in the January 2011 MessageLabs Intelligence Report here. ®