According to Daniel Zatz, security director for Computer Associates Australia, Bagle-A carries an expiry date, possibly indicating more robust versions of the worm could be slated for release soon.
According to Zatz, while Bagle-A is already successful, responsible for an alarming 80 percent jump in queries to CA's help desk and in virus submissions to rival computer security company Sophos, the current version of the worm contains bugs.
Comparing Bagle to the infamous Sobig virus which flooded global e-mail networks last year, Zatz fears that a more virulent version of new worm could appear soon.
"One of our biggest concern is that if we look back a year ago at the Sobig variants, they all had drop-dead dates, and every time one hit that drop dead date a new variant came out; a new and improved variant of it," said Zatz.
Bagle-A is due to expire on the 28th of January, suggesting tuned variations of the worm could appear as early next week.
Bagle-A's creators, like authors of many previous successful worms, have relied on the ignorance and curiosity of e-mail users for the worm's success.
The worm arrives in e-mail inboxes as a message containing few lines of text suggesting the e-mail may be from system administrator, as well as an executable attachment. When the attachment is activated by its receiver the worm then installs a program on the recipient computer that allows the worm to be e-mailed on to other users in the system's local address book.
The worm also attempts to install a backdoor or Trojan on infected machines, listening for activity on port 6777.
Sean Richmond, support manager with anti-virus software vendor Sophos Australia and New Zealand, said the company was still examining the Trojan to see what else it was capable of.
Given that most corporate email servers block transmission of executable attachments, CA's Zatz believes that home and medium-sized enterprise users are responsible for spreading the new worm.
Zatz could give no other explanation for the worm's apparent success than "pure curiosity" on the users' part.
Another possible factor in the worm's success, Zatz said, was the fact the worm's creators programmed the worm to e-mail itself to handful of popular domains to evade swift detection by dominant Web enterprises such as Hotmail, MSN and a large Russian computer security agency.
Richmond said favourable timing may help contain the Bagle. According to Richmond, Bagle's appearance in the Asia-Pacific region should give anti-virus companies adequate time to prepare software and procedures for US and European companies before they open for trading.
Users who suspect their computers may be infected with the virus should look for a file called bbeagle.exe in their Windows System directory. The file disguises itself with Microsoft's familiar calculator icon.