vSkymmer botnet, a financial malware appears in the underground

Pierluigi Paganini March 29, 2013

The principal reports proposed by various security firm demonstrate a sustained growth of cyber criminal activities fueled by increased offer of underground.

In the underground it is practically possible to acquire/sell any kind of product and services to realize illegal activities.

The offer is complete and include programming and hacking services, bulletproof-hosting services, cyber attacks on demand (e.g. DDoS, Spear phishing) and of course any kind of malicious code especially for the creation of powerful botnets.

Despite the number of state-sponsored attacks is increasing in impressive way, underground is mainly referred by cyber criminals that have as primary goal the monetization of fraud scheme.

Botnet products and related services are most requested items in this tumultuous market, in particular cyber criminals demonstrate an increasing interest to banking and payments sectors.

In the past malicious code such as Zeus and SpyEye create serious problems to financial sector causing substantial losses, in these days a new botnet, named vSkimmer, has been  found in the underground and once again it is the menacing payment world.

The security expert Chintan Shah at  McAfee security firm wrote in a blog post that during the analysis of some of Russian underground forums found a discussion about a Trojan for sale that is able to steal credit card information from for financial transactions and credit card payments.

vSkimmer agent works on Windows machine, it detects card readers on the victim’s machine and gather all the information from pc sending it to a remote control server encrypting it (Base64).

The malware collects the following information from the infected machine and sends it to the control server:

  • Machine GUID from the Registry
  • Locale info
  • Username
  • Hostname
  • OS version



Security community indicates vSkimmer as the successor of the popular Dexter, a popular malware that targeted Point-of-Sale systems to gather card data as it is transmitted during sales flow. The case is not isolated, Dexter is responsible for the loss of nearly 80,000 credit card records and data breach of payment card data of Subway restaurants in 2012 meanwhile several days ago, Group-IB has found a new type of POS malware, «DUMP MEMORY GRABBER by Ree[4]”, written on pure C++ without use of any additional libraries. It supports all Microsoft Windows versions including x64 versions and use mmon.exe for RAM memory scanning on tracks and credit card data.

According to security experts at McAfee vSkimemr is circulating in the underground forums since February and it could an ongoing project, vSkimmer is very complex but despite it appears more sophisticated of Dexter it is easier to use.

Exactly as its predecessor Dexter, vSkimmer is completely undetectable on the compromised host, it operates silently waiting for a named USB device to be attached to the compromised machine and once detected it the malware dumps the collected data to the removable device.

vSkimmer can also grab the Track 2 data stored on the magnetic strip of the credit cards. This track stores all the card information including the card number.”

Following an extract from McAfee post:

VSkimmer maintains the whitelisted process, which it skips while enumerating the running processes on the infected machine.Once vSkimmer finds any running process not in the whitelist, it runs OpenProcess and ReadProcessMemory to read the memory pages of the process and invokes the pattern-matching algorithm to match the regular expression “?[3-9]{1}[0-9]{12,19}[D=\\u0061][0-9]{10,30}\\??”)” and extract the card info read by the payment devices. This is done recursively for every process running in the infected machine and not on the whitelist.”

another example of how financial fraud is actively evolving and how financial Trojans are developed and passed around in the underground community.”

The malware represents, according to the security community, one of the first examples of malicious code that directly targets card-payment terminals running on Windows machines,  the offer of similar agents in the underground is increasing and their sale systems appear very efficient and able to respond to user’s needs.

A new generation of malware will attract more and more, hordes of criminals looking to profit … is important to continue to monitor the supply in the black market.

 Pierluigi Paganini

(Security Affairs – Botnet)

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