Background on OSX.Trojan.iServices.A & .B:
Back in January, it was discovered that a trojan horse was running around on the Internet affecting OS X.
There have been a handful of these things in the last few years, but this was the biggest one to date.
The trojan horse was bundled inside an iWork 09 (which has just been released) installer available on several bit torrent sites.
The iWork trojan horse piggy-backed on the legitimate iWork Installer (this getting an administrator password to install itself) and installed a package named iWorkServices.pkg in the /System/Library/StartupItems folder with read-write-execute root privileges – meaning that these packages were started as boot with admin privileges, meaning any future actions could be completed without user intervention. Anything in the System/Library/StartupItems folder is a big deal because is affects all users on the system. Thus, even trashing a user and creating a new one, doesn’t kill the iWorkService package.
It is unclear how many Mac users were affected by this trojan horse. On January 22, Intego estimated that the number was at least 20,000.
A similar trojan horse popped up in a Photoshop CS4 torrent a few days after the iWork installer was discovered. Named OSX.Trojan.iServices.B, this trojan horse affected the application that would crack Photoshop so the user didn’t need a legitimate serial number. The crack application asks for an admin password, then copies an executable to /usr/bin/DivX, then creates a startup item in /System/Library/StartupItems/DivX.
Both trojan horses listened to traffic from the Internet, and would send small bits of data to 2 IP addresses, assumedly “calling home,” but nothing ever really happened – the infected Macs have sat dormant.
What Changed This Week:
This week, Macworld reported that the trojan horses may be doing something:
Two researchers, Mario Ballano Barcena and Alfredo Pesoli, have now discovered two separate variants of the malware, each using distinct techniques to compromise users’ machines. They also conclude that the author of the malware was not the same person using it to launch the denial-of-service (DoS) attacks on Web sites including, according to the Washington Post’s Brian Krebs, a site called “dollarcardmarketing.com.” The infected package has apparently been download several thousand times, though it also needs to be installed in order to do its dirty work.
And from that Washington Post article:
I interviewed Pete Yandell, a software developer from Australia and curator of notahat.com, whose Mac was infected with this malware. Yandell informed me that as a result of his installing this modified iWork software, his Mac was ensnared in a botnet that was attacking a Web site called dollarcardmarketing.com.
In that story, I also interviewed the owner of dollarcardmarketing, who said his site was hit with a distributed denial of service (DDoS) attack that generated more than 600Gb worth of Web traffic more than the usual monthly amount, suggesting that whatever botnet hit his site was fairly sizable.
The research Macworld was referring to appears (at least by reading the Post story) to be recycled info, but that’s beside the point.
So, to review, it appears that the trojan horse was (or is) generating lots of traffic to dollarcardmarketing.com, shutting down the site. While the timeline is a bit fuzzy, the attack shows that the trojan horse proved to be at least somewhat effective.
What This Means:
So who gives? Everyone knows that torrenting software is not only stealing, but is risky. But this attack shows that the malware-building types are looking toward the Mac as a viable platform to attack.
In the past, two things have kept the Mac safe from these types of incidents.
First, OS X requires the user to enter their admin password to install software. The iWork trojan horse gets around this by simply adding another package to the payload for OS X’s Installer to process. This is probably how future trojan horses will work as well, since it is so simple and elegant. Very, very few people log at Installer’s log files during or after an installation, letting the additional files to be installed right before their eyes without them knowing.
Secondly, Apple’s market share is so low, it’s not economically viable to attack the Mac. While Apple’s market share has leveled off in the recent quarters, it is bigger than ever before, but with more Macs in businesses, they are more worthwhile to break into. And if this attack proves anything, it shows that malware developers are seeing the Mac as a possible target for really the first time.
Security Measures:
As far as the big picture, Apple has done a good job at keeping OS X safe. I think security is in the hands of the users. While I don’t think we’re at a point where antivirus* is a necessity, common sense is.
Don’t download software from the seedy underbelly of the Internet. It’s stealing and it’s risky.
Have a good, strong password, and if your Mac asks for it, be sure you know why – especially if you’re installing something you already know to be questionable.
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*If you want a free, OS X antivirus program, check out ClamXav.