Flashback Malware Still Affecting over 100,000 Macs

While Apple has pushed out several software updates to detect the Flashback malware and remove it from infected systems, Symantec noted late yesterday that over 100,000 machines remain afflicted by the issue as detected by their sinkhole operation to redirect server traffic.

Symantec pegged the number at approximately 142,000 as of Monday, listing a rough estimate of "over 99,000" as yesterday's data was still coming in. Those numbers are down from a peak of over 600,000 machines two weeks ago, but a substantial number of machines are still infected by the malware.

The statistics from our sinkhole are showing declining numbers on a daily basis. However, we had originally believed that we would have seen a greater decline in infections at this point in time, but this has proven not to be the case. Currently, it appears that the number of infected computers has tapered off, but remains around the 140,000 mark.

As there have been tools released by Symantec and other vendors in the past few days concerning this threat, the infection numbers should have seen a dramatic decrease by now.

Symantec also takes a look at the domain name generator that allows infected machines to connect to their command-and-control servers to receive instructions. The generator uses a list of 14-character strings rotated each day, coupling each string with one of five top-level domains (.com, .net, .info, .in, or .kz) to find its instructions.

The report also claims that Flashback-infected systems can receive updated command-and-control server locations through Twitter, although no details on that process are provided. A similar claim was made for earlier versions of Flashback, although there has apparently been no demonstration of the Twitter delivery method actually being used.