Security researchers at Symantec have uncovered what they suspect may be the first Mac OS X botnet launching denial-of service attacks.

As revealed in a recent edition of Virus Bulletin, the researchers claim to have found two malware types which use different tricks to grab control of infected Mac OS X machines.

The two malware bundles are called OSX.Iservice and OSX.Iservice.B, and appear to be spread within pirated copies of iWork 09 and Photoshop CS4, distributed on the popular P2P torrent network.  We’ve talked about these before but now these infected machines are springing into action.

Seems the malware maker got hold of original copies of both application and inserted the malicious binaries into the software. Users who download and install these apps may then be affected.

Researchers Mario Ballano Barcena and Alfredo Pesoli warn this to be “the first real attempt to create a Mac botnet”, and state that these zombie Macs are already going about bad business. Thousands of Macs may have been infected, they warn.

The men also note the malware author appears to have used the most flexible and extendible approach when creating the code, “therefore, we would not be surprised to see a new, modified variant in the near future,” the researchers said.

We’re attempting to unearth further information at this time.

UPDATE: We’ve managed a little chat with Symantec, details follow:

– The infection is also known as: OSX/iWorkServ.A [F-Secure],    OSX/IWService [McAfee],    OSX/iWorkS-A [Sophos],    OSX_KROWI.A [Trend],    OSX/iWorkS-Fam [Sophos],    OSX/Krowi.A [Computer Associates].

– They warn: "Users who download files from third party sites and from P2P networks such as BitTorrent are at risk. More generally, anyone who surfs the internet should be aware of the threat of fake web sites, called phishing sites, that steal passwords, identity information and credit card numbers. "

– Asked if Mac users are under attack, Symantec notes: "The short answer, no. Users of Macintosh computers continue to have little to fear from viruses, trojans and worms so long as they take reasonable precautions."

More general info on the malware:

The two versions of the trojan, called OSX.Iservice and OSX.Iservice.B both create a network of computers (a “botnet) that can used by cyber criminals to attack web sites, send junk email, steal passwords (SPAM) and other malicious activities. This network has been called by some, "iBotnet".

The trojans are distributed in pirated copies of Apple Computer’s iWork ’09 and Adobe Photoshop CS4 found on some P2P networks. Other than installing the company’s anti-virus technologies (and warning against free solutions purporting to do this. as these are often flawed), the company advises Mac users who frequently download files and apps should, "Create a limited or non-administrator account for day to day activities. Use an account with full privileges only when necessary."

The fake iWork ’09 installer has the filename and is approximately 450MB in size. In contrast, the legitimate trial version of iWork ’09 that is available from Apple is named iWork09Trial.dmg and is slightly over 451MB. The iWorkServices.pkg contains the Trojan executable named iworkservices, and is approximately 404KB in size.

The Trojan first determines if it is the root user on the compromised computer and if not, it will end. Then, it checks to see if it was executed with the file name iWorkServices. If not, it will create the following folder:


The Trojan then copies itself to both of the following locations:



It then modifies the following file to ensure that it runs when the compromised computer restarts:


The Trojan then restarts itself from its new location in /System/Library/StartupItems/iWorkServices, and decrypts an AES encrypted configuration file, which is located in /private/tmp/.iWorkServices. Finally, the Trojan acts as a back door and opens a port on the local host for connections. It then attempts to connect to the following remote hosts:

We’re fairly confident now this isn’t a wide-spread outbreak, but do hope that any Mac user who may have been affected now has the knowledge they need to identify if indeed they have been, and potentially to protect themselves from any further propogation of this malware thingummy…

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