When Antivirus Fails, All Is Not Lost

Starting in late 2011, unknown attackers attempted to install malicious code on a computer belonging to a client of security firm Bit9. The attack, which occurred around 6 a.m. each day, failed because the company's whitelisting technology did not recognize the program as an approved application and blocked its installation.

Only recently was the attack given another name: Flame.

Although Bit9 and its client, which the company would not name but says is based in the Middle East, did not investigate the routine security incidents last year, recent events convinced Bit9 to search through its database of hashes to identify past executables that its technology had blocked. When it found a match, the company--with permission--performed forensics using the client's local database of security events. Bit9 found that a dropper had attempted to install at least two different files on the targeted system.

"Somebody had remotely targeted that system and compromised it enough to try to remotely drop executables on the computer, and we flagged them as unauthorized," says Harry Sverdlove, chief technology officer with Bit9. "It attempted to run. We said no, and that was the end of it."

Following Flame, the most recent targeted attack to hit the headlines, antivirus companies are facing a great deal of criticism for missing signs of the attack for more than four years. Even one of the industry's own, Mikko Hypponen of F-Secure, issued a mea culpa in Wired, saying that the company and its competitors could do better.

"All of us had missed detecting this malware for two years, or more," F-Secure's chief research officer wrote. "That's a spectacular failure for our company, and for the antivirus industry in general."

[ Microsoft issued an emergency patch for all versions of Windows after it discovered the attackers had abused one of its digital certificates to help spread the Flame infection from one machine to others within the targeted organization. See Flame Burns Microsoft With Digital Certificate Hack. ]

Historically, however, antivirus software's strength has been in detecting viruses, worms, and other mass attacks. More recent improvements, such as threat communities and cloud analysis, continue to shorten the delay between detection and the distribution of specific protections. Yet antivirus and anti-malware programs continue to be ill-suited to detect low-volume threats like targeted attacks.

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