It's been about a year since Conficker/Downadup hit in 2009, and although the threat didn't turn out to be as grave as it had the potential to be, the 6.5 million PCs that remain infected today represent what Symantec calls a "loaded gun, waiting to be fired".
In a blog post on Symantec's website on the anniversary of Conficker's 1 April "trigger date" an employee writes that those PCs that remain compromised are infected with either the A or B variant and are still very much vulnerable to further attack.
"Thus far, the machines still infected with Downadup/Conficker have not been utilised for any significant criminal activity, but with an army of nearly 6.5 million computers strong, the threat remains a viable one," wrote Vincent Weafer.
The C variant, which relied on a peer-to-peer method of spreading, is slowly being eliminated, going from 1.5 million infections to about 210,000, the post read.
Conficker is one of the biggest botnets ever assembled but somebody has yet to pull the trigger, said Brian O'Higgins, an Ottawa-based independent security consultant. "It's always been a threat and it's been there for a year or so," said O'Higgins.
But its sheer size renders an advantage to the security community because it means that researchers have monitored it to the degree that if anyone tried to use the botnet now, they would be detected very quickly, said O'Higgins.
"(The criminals are) in a risky area," said O'Higgins.
Although dormant, the botnet definitely presents a threat, but the circumstances are somewhat different now given the level of awareness Conficker has raised, said Warren Shiau, senior associate with Toronto-based research firm The Strategic Counsel.
"Whether or not (the threat is) actually realised is a different matter, because it's known and generally it's harder to take advantage of an infection when it's a known infection," said Shiau.
Major security problems most often occur at the outset of any new threat, said Shiau. "It's the immediate experience that is most threatening," he said.
Conficker trolled the web in the early months of 2009 seeking out the millions of PCs unprotected by security software, exploiting a security vulnerability in Windows 2000, Windows XP and Windows Server 2003 systems. Microsoft had already released a patch, MS08-067, to protect against this in October 2008.
In early 2009, one security vendor warned that the dormant worm may have only been undergoing a test run to be unleashed at a later date with an even greater vengeance. Jason Miller, manager of security and data at St. Paul, Minn.-based security technology vendor Shavlik Technologies LLC, at the time said that Conficker was not going away.
"Whoever wrote this virus has a lot of information tucked in their head," said Miller, referring to the sophisticated techniques employed by Conficker.
But as for the end user's perception of PC security a year later, Shiau doesn't think that Conficker's milder-than-anticipated damage has made users overconfident about securing their machines.
Shiau said the average end-user is not an IT professional who remains abreast of current security threats, so security knowledge is not based on specific threats. Rather, it's about changing behavioural patterns concerning security as a lifecycle, like maintaining an up-to-date antivirus software.
"Consumer overconfidence is rooted in much deeper behavioural issues," said Shiau.
On Symantec's blog, Weafer writes that we're not out of the woods just yet with Conficker and its army of 6.5 million infected PCs. Weafer cites another botnet, Rustock, that sends out 32.8 per cent of overall spam and sits on between 1.6 and 2.4 million machines.