"It has been reported that variants of a new banking Trojan dubbed as 'Dyreza' are spreading. The malware mainly targets the customers of well-known financial institutions running Microsoft Windows operating system.
"It propagates by using social engineering techniques or by means of spam messages pretending to be genuine mail received from financial institution containing either a Zip or PDF as an email attachment exploiting the vulnerability in unpatched versions of Adobe Reader to download the malware.
"The ZIP contains a self executing malware which installs itself on the target system on being extracted," the Computer Emergency Response Team of India (CERT-In) said in its latest advisory to users of online banking system.
The CERT-In is the nodal agency to combat hacking, phishing and to fortify security-related defences of the Indian Internet domain.
The agency said the malware is capable to wreak havoc into a secure system in a number of ways.
The 'Trojan' virus, an unauthorised programme which passively gains control over another system by representing itself as an authorised programme, steals infected bank customers' online banking credentials, can bypass secure protection settings using browser hijacking, can capture keystrokes, perform man-in-the-middle attack to intercept network traffic and communicate with command and control server, the agency said.
Once the spam mail is received by a bank customer, the agency said, it "entices" the user to download and extract the Zip file which then begins its destructive and stealing action.
The virus is categorised as "deadly" as it can acquire as many as ten aliases to evade anti-virus updates.