A new large-scale malware outbreak is currently believed to have infected at least 50 of America’s Fortune 100 companies.

Over 70 variants of the malware, known as Mariposa, have been identified, with complex methods of action including email address harvesting, injecting code into known system processes, and downloading further malware onto corporate computers and networks. 

Like Conficker, this new malware can spread by multiple mechanisms, including running automatically from USB flash drives, via an Internet-based update module, and across the MSN Messenger chat network.

Also like Conficker, the exact motivation or the people behind the threat are not known.  But it’s worth checking your AV signatures are fully updated – and we would recommend the use of secure USB drives with onboard anti-malware protection, too.

As you may have seen in the last week or so, the latest version of Apple’s Macintosh OS, known as Snow Leopard, includes for the first time features to detect and warn users about some types of malware.

However, a number of external parties have tested these features, and found that they will only detect the specific malware if it’s encountered via a Web browser.  The features will not detect malware if it is carried and inserted into the machine via a removable drive, such as a USB flash drive.

Although Apple has said for many years that Mac users don’t really need to worry about malware, the threat landscape is constantly changing.  So Mac users should be careful about possible infections from any source, whether on the web or by removable media.

With around 250 data breaches publicly reported in the United States between Jan. 1 and Jun. 12 this year, rogue employees and hackers were the major causes according to figures released this week by the Identity Theft Resource Center.

Theft by employees and hacking were each responsible for 18% of all incidents, an increase of around 10% compared with the same period in 2008.

The Center also found that 14% of breaches so far this year were due to data contained on lost or stolen digital media, such as a laptop or USB thumb drives.  That’s still a significant number – and all the more reason to consider using a secure USB flash drive solution, such as our Cruzer Enterprise range.