Earlier this month researchers at Red Canary squashed an attempt by malicious actors to place and execute malware on Ask.com's toolbar.
The attempt involved a number of Windows processes associated with Portable Executable files having abnormal extensions, and even though this can appear legitimate Red Canary said in its blog that in this case the behavior was picked up because it was suspicious in the context of the application being targeted. The attack was not noticed or defended by the anti-virus software.
If it had been successful the attack would have co-opted Ask.com enabling it to distribute malware including banking trojans and online fraud code. A successful attack on such a site could lead to thousands or millions of computers being quickly infected, said Keith McCammon, Red Canary's CSO, in the blog.
Red Canary warned Ask.com and that company quickly issued an update blocking such attacks.