Apple Changes Security Playbook With Flashback Response

Responding to malware spread by the huge Flashback botnet, Apple has for the first time come clean about a threat before it's readied a fix. Is it a new security day in Cupertino?

Mathew J. Schwartz, Contributor

April 12, 2012

4 Min Read

Stunned by the revelation that 1% of all OS X Macs may have been hijacked by a Java botnet named Flashback, in the largest Apple malware outbreak in history? For Mac security watchers, that's nothing compared with the first-time revelation from Apple--wait for it--that it's still coding a fix for a security issue.

"Apple has--apparently for the very first time!--talked about a security problem before it had all its threat response ducks in a row," blogged Paul Ducklin, head of technology for Sophos in the Asia Pacific region.

Indeed, in a security bulletin titled "About Flashback malware" released Tuesday, Apple said that it's taking direct aim at the malware in two ways: "Apple is developing software that will detect and remove the Flashback malware. In addition to the Java vulnerability, the Flashback malware relies on computer servers hosted by the malware authors to perform many of its critical functions. Apple is working with ISPs worldwide to disable this command and control network."

[ Apple rejects iOS apps that use unique identifier numbers over privacy concerns. Read more at Apple Rejects Apps Over Privacy Concerns. ]

Apple has historically downplayed any security issues affecting Mac OS X, detailing them only in the release notes for operating system updates. Exceptions--such as last year's outbreak involving fake security software known as MacDefender--are rare. In that case, Apple offered detailed guidance for avoiding the malware, while also acknowledging that it was hard-coding blocking tools into Apple OS X.

So what's behind the more recent security information disclosure shift? For starters, there's the scale of the outbreak. Kaspersky Lab said that last week it saw 670,000 active machines infected with Flashback (aka Flashfake). While that number had dropped to 237,103 by Sunday, the company warned that the botnet remains active. "The decrease in infected bots does not mean the botnet is rapidly shrinking. The statistics represent the number of active bots connected to Flashfake during the past few days--it is not the equivalent of the exact number of infected machines," read a statement released by Kapersky.

But the Flashback eradication campaign was also personal: at least 274 infected Macs were located in Cupertino.

Here's where the fixes stand: Last week, Apple pushed an update for Mac OS X v10.6 and 10.7, fixing the bug in the Oracle Java software. (Mac OS X automatically checks for updates weekly, but users can trigger updating by running Software Update.)

Users of older Mac operating systems, meanwhile, are still waiting for a permanent fix. Apple said that until that happens, they can disable Java, but is that really feasible? "Suggestions to ditch Java are unhelpful and unlikely for the average user. It is far too ubiquitous," said Adrian Sanabria, a security engineer at Sword & Shield Enterprise Security who's been tracking the outbreak.

Furthermore, quitting Java is hard to do, especially since some software--such as Adobe's CS5 suite, which includes Photoshop and Dreamweaver--requires a Java runtime environment to be installed. Otherwise, they won't run.

Another option is to take direct aim at the malware by using free Flashback detection and removal tools released by Russian antivirus firm Dr. Web. Kaspersky Lab likewise released its own Flashback detection and removal tool.

If the Flashback Trojan infects a Mac, it redirects the computer to a Website that pushes JavaScript that loads a malicious Java applet containing the exploit. But it's interesting to see what will make the malware not install itself. Namely, the malware first scans the hard drive, looking for the Little Snitch firewall, Packet Peeper network protocol analysis software, Apple's Xcode development tools, or one of a number of different antivirus products for Mac OS X, all of which would help detect the threat. For unknown reasons, the application also looks for Skype or Microsoft Office. If it finds any of those applications installed on the Mac, it deletes itself without executing the malicious payload. In other words, using Mac security software, at least in the case of this malware, pays off in more ways than one.

On the outbreak scale, how does Flashback rank compared to malware seen on Windows? What's notable is that Apple has been pushing operating system updates to nuke the threat, meaning that users of current versions of Mac OS X are seeing fixes get automatically installed. By comparison, Windows users must still rely on antivirus add-ons to help them spot and block such threats.

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About the Author(s)

Mathew J. Schwartz


Mathew Schwartz served as the InformationWeek information security reporter from 2010 until mid-2014.

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