Dref and Stratio top December malware list

Dref and Stratio were the big hitters in December

The Dref and Stratio malware were the big hitters when it came to threats in December, according to figures from antivirus companies.

Sophos said that Dref, which disguised itself as a new year email greeting, was so prevalent in the last few days of 2006 that it pushed Stratio off the top of the malware chart.

Dref was only discovered on 30 December but had accounted for 93.7 per cent of infected emails by the following day, with Stratio falling to fourth place with just 7.8 per cent of the total.

"Having spread for only two days during the entire month, it is astonishing that Dref has secured the top position for the most widespread piece of malicious code," said Carole Theriault, senior security consultant at Sophos.

"Dref has been spammed out far and wide in the past few days, and there's a danger that, in the rush to get through the backlog of holiday emails, people might return to work and accidentally launch the malicious attachment."

However, Kaspersky's monitoring found that Stratio, which the antivirus company calls Warezov, held the top three spots in December 2006. 

"In December Warezov variants took the three top positions in the rankings, while the traditional change of leader turned into a family affair with Warezov.fb replacing Warezov.gj," said a statement from Kaspersky.

"We had expected and predicted this change. In December the former leader's ranking declined sharply as it yielded position to its newer brethren."

Old favourite Netsky was the next most prevalent threat in fourth and fifth spots, according to Kaspersky's figures, accounting for 14.28 per cent of malware.

However, despite the return of old threats, Sophos found that the proportion of infected email continued to remain low, at just one in 337 or 0.3 per cent.

Sophos identified 6,251 new threats in December, bringing the total number of malware it protects against to 207,684.