As mentioned in our previous blog entry, most of the Trojan.Clampi features reside in separate modules that are sent by a remote server in response to clients’ queries. In this part of this blog series, we’ll have a look at one of the modules used by the malware to steal login credentials mostly from banking Web sites.
 
This module is codenamed LOGGER by the threat. After decryption, the beginning of the module’s raw data looks like this (compressed):

To avoid downloading the module each time Clampi runs, it is stored in the registry (in an encrypted form) in a value named “Mxx”, where “xx” is a zero-based number...

Trojan.Clampi is one of the hottest malware around, and as such, received a fair amount of media coverage, as well as technical reports describing some of its functionalities. As part of our ongoing blog series, we will be discussing interesting and rarely presented aspects of Clampi. Today, we’ll introduce an important aspect of Clampi: the network communication.

First of all, if you’re not familiar with this malware already, Clampi is a Trojan horse whose main purpose is to steal private information: user passwords, login credentials, software licenses, credit card numbers, bank account information, etc. Note that Clampi’s operations are performed by helper modules, downloaded by the main executable, and stored in the Windows registry.

Once the threat is installed on a computer, it connects to one of the gateway servers listed in the registry value “GatesList...

It is not very common for a file infector to do more than simply introduce trivial modifications to the files it infects. Virus authors usually avoid complex modifications to the files because of the possibility of corruption. W32.Xpaj.B is one of exceptions.

W32.Xpaj.B is an entry-point obscuring, polymorphic file infector. The virus is not completely new and shares some of its characteristics with its predecessor, W32.Xpaj, first seen in June 2008. What sets this creature apart is the amount of effort its authors have invested into hiding their malicious code in the files it infects.

W32.XPaj.B is more sophisticated than your average file infector. To make finding its malicious code difficult, the virus avoids putting any obvious signs in the infected files. Unlike most simple viruses, it doesn’t attempt to execute the virus code by hijacking control when the infected file is started. Instead, the virus overwrites some subroutines from the infected files with...

Have you ever noticed how movies tend to come in waves? A few years ago it seemed like every action movie had a space theme; then the following year the big new movies featured some kind of natural disaster. This past summer it seemed like every other movie was in 3-D. Technology, as we all know, has waves too, and the security industry is no different. For example, recently there has been a lot of talk about reputation-based security and suddenly it seems like every vendor is claiming to have some type of reputation technology. But, not all technologies are created equal, so I thought I’d take a few minutes to look at what makes Symantec’s reputation-based technology so very different.

Why is a new approach needed?

Two fairly recent trends have had a negative impact on the effectiveness of traditional approaches to security. First, many of today’s threats are highly polymorphic—they are able to easily hide because nearly every instance of...