Malware which threatens the global network of computers is so diverse that top-10 malicious programs only account for nearly 30% of the market. BitDefender has released a chart with the most "annoying" trojans and other types of software that affect users' machines. "Annoying" because the company itself admitted that threats are more difficult to identify and destroy than dangerous.

The top 10 most common threats in July and their percentage is indicated bellow:

1.Trojan.Clicker.CM - 6.63%
2.Trojan.Downloader.WMA.Wimad.N - 4.49%
3.Trojan.Downloader.Wimad.A - 2.91%
4.Trojan.Qhost.AKR - 2.57%
5.Exploit.SWF.Gen - 2.39%
6.Trojan.Swizzor.1 - 2.02%
7.Trojan.HTML.Zlob.W - 1.92%
8.Trojan.HTML.Zlob.AA1 - 73%
9.Trojan.Autorun.TE - 1.72%
10.Trojan.FakeAlert.PP - 1.65%
Others - 71.97%.

Nine out of ten most encountered threats are trojans, which can be easily covered by what seem to be legitimate applications. Once installed, trojans can lead to data erasure or corrupting or even enable a remote control over the computer, which are the basis of phishing attacks and botnet creation. The first trojan in the list, Trojan.Clicker.CM, displays several commercial pop-ups, which "eat" an important part of the bandwidth and, as a consequence, slow down the computer.

BitDefender indicates that these are not new threats, as only two of the most common ones in July are new entries. Trojan.Downloader.Wimad.A, which holds the third position in the chart, has a great mobility and can appear "in different locations on the Internet, in sharing networks or media download sites or even in spam". The second new entry is Trojan.Swizzor.1, designed as an "obfuscated" downloader (meaning that its name is written with different characters every time, to make it harder to detect, without changing the meaning) that acts as an intermediate entity between other types of malware and the victims' machines.

"We are seeing the beginnings of the Internet flu - instead of mega-killer pandemics, we have these recurring infections that are not very dangerous in and of itself, [sic] but pervasive, hard to identify and stamp out," said Sorin Dudea, Head of BitDefender AV Research.