Flashback - Are You Joking? There is No Malware for Mac!

Monday, April 23, 2012

Pierluigi Paganini

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(Translated from the Oringinal Italian)

Recently I discussed with my friend and colleague Francesco the lack of awareness by Apple users about malware that plagues the products of the house in Cupertino. 

This myth is one of the reasons for the success in malware development for Apple, as the users totally ignore that Apple machines are equivalent to any other kind of other OS.

Asking them information regarding viruses or trojans for their MAC they will reply you:

"Are you joking? There aren't malware for Mac"

Obviously another reason is related to the large diffusion of the Apple systems that in the recent years has significantly increased their market share, attracting curious hackers, cyber criminals and government agencies. 

The process is natural and to demonstrate the high interest in the Apple's products and their vulnerabilities let's take a look to the price list of 0-Days Exploits ... well 0-Days Vulnerabilities for MAC are the most expensive on the black market.

(click image to enlarge)

For several years we have seen that Apple is not immune to malware, it's code is rich with vulnerabilities like any other, and during the various security conferences its products have been exploited. The Flashback Trojan was created to conduct click fraud scams by hijacking people’s search engine results inside their web browsers and stealing banking or login credential.

Of course one infected the system it could be used ad part of a botnet causing bigger problems. The botnet related to the Flashback Trojan is called Flashfake and was also designed by cyber criminals to conduct a click fraud scam, taking advantage of pay-per-click campaigns by advertising companies.

Flashback was created in September 2011 and disguises itself as an Adobe Flash Player installer, using a Flash Player layout. Once installed, the malware searches for user names and passwords stored on the victims device.

The botnet trojan Flashfake in more recent versions was being installed via a client-side Java exploitation, but what is really interesting is that none of THE exploited vulnerabilities targeted with client-side exploits were 0-day.

It is interesting to note the time interval from the original Oracle Java security update and the release for Apple Java. The duration of the interval is worrysome, giving cybercriminals time to prepare of use available exploit packages to exploit the vulnerabilities.

Look at the detailed timeline of Oracle Java releases and Apple patches for the three main Java vulnerabilities exploited:

CVE-2012-0507

2012-02-15 Oracle patches Atomic Reference Array vulnerability

2012-03-10 First Itw exploits targeting the vuln

2012-03-30 Metasploit developers add Java atomicreferencearray exploit module

2012-04-03 Apple patches their code

CVE-2011-3544

2011-05-12 Reported to vendor

2011-11-18 Oracle patched their Java SE

2011-11-30 Metasploit developers add "Rhino exploit" module

2011-11-30 Krebs reports operational Blackhole site with the new Java exploit

2012-3-29 Patched by Apple

CVE-2008-5353

"Deserializing Calendar objects"

2008-08-01 Reported to Sun with first instance of the vulnerability

2008-12-03 Sun patches their code (Sun link down)

2009-05-15 Apple patches MacOSX code

2009-06-16 Metasploit developers add Java deserialization exploit

The gap demonstrates the serious problem presented by the open door for the attacks that exploit the known vulnerabilities that we call 1-day exploits.

The Metasploit Framework is a tool for developing and executing exploit code against a remote targeted machine, by using it is is possible to create a fake Java applet that requests the user to update their system.

A dialog box is presented to the users according the Metasploit exploit module list on released on 2010-01-27.  The attackers present the user with a file that he thinks is a Java Update provided by Apple Inc, which they trust to perform any action on their machine.

At this point the downloader module of the malware will then communicate with a command and control server (C&C) to register and download new Flashfake components.

According Kaspersky Lab experts:

"These components in turn, collect the system UUID and timestamp, then auto-generate with a crypto algorithm a set of C2 domains, along with maintaining a list of hard coded domains. A couple of the newer components inject into running processes on the system hooking software functionality and hijacking traffic, much like past TDS malware."

Kaspersky Lab said that the number of active bots for Flashfake is decreasing, dropping from more than 650,000 infected computers to just 237,000, but we must monitor the phenomenon because the botnet is still active. 

Since not all Mac users updated their system, the malware is still infecting Macs those which do not have the patch installed.

Says Gostev: “We recommend users update their systems immediately with the latest security update from Apple.”

We must remember that in any software there will be vulnerabilities that could be exploited for criminal purposes. To give you an immediate idea of the malware available for the Mac environment, I produced a table that lists the main agents detected by a well known antivirus.

(click image to enlarge)

Software is written by human beings, and mistakes and coding vulnerabilities are part of life cycle of software. It's a question of time, but cybercriminals moved by economical incentives will invest heavily in those sectors where the business opportunity is high, as criminals follow the money.

Today Apple is a suitable field to invest in. I believe Apple must change its approach related to security and malware by starting awareness campaigns about the growing cyber threats and promoting the adoption of software protections.

Cross-posted from Security Affairs

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