Security analysts at MicroWorld Technologies say that 'Win32.Detnat.a' is a network worm that infects uncompressed Portable Executable (PE) files. With its unique algorithm and polymorphic nature, the worm employs a different mode of encryption each time it infects a file, while keeping the file size unchanged, making it hard to detect.

Detnat.a spreads on shared network resources and file sharing programs. At the second level of attack, the worm goes ahead and downloads 'Infostealer.Lineage', a Trojan that steals usernames and passwords of popular online game 'Lineage' and passes it on to the remote attacker. With its dynamic nature, Detnat can invite any other Trojan as well, if the writer of the worm decides to.

One needs to be extremely careful while downloading executable attachments via e-mails or from the Internet, says Aneesh Paliwal, security analyst at MicroWorld Technologies. A single infection in a workstation can proliferate in shared networks in no time. People using file sharing programs are particularly vulnerable to this mode of data corruption and theft.

Individual users and subgroups can freely exchange files in the internal networks of most organisations. This makes it easier for the spreading routine of a worm like Detnat. If the worm stations itself in the start-up folder of the workstation connected to a network, then it will come back every time when that computer reboots, even if one cleans up the entire network. In a more targeted operation, an attacker hitting the server can ensure that every user logging on to that server gets infected, points out Paliwal.

A large number of new and emerging Viruses and worms are targeting enterprises and their external and internal networks, to carry out a whole lot of nefarious activities, observes Govind Rammurthy, CEO of MicroWorld Technologies. Often, malware creeps in through those vulnerabilities that we tend to overlook. One needs to safeguard the corporate e-mail system, intranet and total Internet access with great vigil as network infections can severely impact the business continuity of enterprises.