A single family of Trojans accounted for more than 60 per cent of malware infections in September, according to Fortinet.
The RogueSecurity Trojan and its variants accounted for 61.5 per cent of all malware attacks during the month, taking the top four positions in the security firm's malware list.
"Not since the start of this year when the notorious Storm virus made a continuous run of devastating attacks has any comparison been seen with this level of activity," said Fortinet.
"However, where the Rogue security applications excel is the accumulated volume, maintaining these extreme levels of activity for at least six days, not to mention the other variants."
The bulk of malware activity occurred in the second and third week of September, with the W32/Inject.GZW!tr.bdr Trojan peaking at nearly two million in the middle of the month.
RogueSecurity Trojan dominates September attacks
By Iain Thomson on Oct 2, 2008 10:02AM