Flashback Malware And The Confusing Case Of The Apple Flashback Malware Remover v1.0

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[Updated 2012-04-18:
Symantec are now reporting that, according to their data collection, the Flashback botnet is down to 140, 000 Macs. That's still a vast number, but a remarkable improvement thanks to Apple's Java update and Remover. 

Symantec: Flashback malware now down to 140K machines

Also new: 
My net friend Al Varnell, who performs a great deal of vigilant work with ClamXav and the ClamAV project, has provided me with new information and insight reflected below. Of greatest interest is the fact that the Flashback malware series has been specifically aimed at Intel CPU Macs only. PPC Macs are immune.]


Apple has provided a separate tool for Mac OS X 10.7 users (only) for the removal of most versions of the Flashback malware. It is entitled (despite odd journalist claims to the contrary) the 'Flashback Malware Remover.' Apple also call it their 'Flashback malware removal tool.' The Software Update system in 10.7 is offering the tool to those who have no installed Java. Optionally, you can manually download it from Apple's Downloads site:


http://support.apple.com/kb/DL1517


Here is Apple's description of the Flashback malware removal tool:

About Flashback malware removal tool 

This update removes the most common variants of the Flashback malware. This update contains the same malware removal tool as Java for OS X 2012-003.If the Flashback malware is found, a dialog will be presented notifying the user that malware was removed. 

In some cases, the Flashback malware removal tool may need to restart your computer in order to completely remove the Flashback malware. 

This update is recommended for all OS X Lion users without Java installed.

Why does the description say 'without' Java installed? Because there have been quite a few versions of the Flashback malware that did not involve Java. Mac users who do not have Java installed (which is the default starting with Mac OS X 10.7) would never have been offered Java for OS X 2012-003 via Software update and therefore would never have run Flashback Malware Remover on their Macs via that update. Rather than leaving those users out in the cold, Apple have provided the Remover as a standalone installer application.


NOTE: The Remover only runs on Mac OS 10.7. I checked.


What is confusing about the Remover is that Apple have NOT provided an actual application tool. Instead Apple has provided an 'installer' package that runs within their Installer program and that is ALL that it does. 

Essentially, Apple took the Java for OS X 2012-003 installer and removed everything except the Remover process from the installation. In other words: NOTHING is installed on your Mac. Not-a-thing. And yes, that is freaky. The installer is the Remover. Get it? This is going to freak out and confuse quite a few Mac users. This has already been proven to be the case up on Apple's Discussion forums at their Support site. I can't blame them! It makes no sense, except that Apple had the Remover handy inside their Java for OS X 2012-003 installer, so they sped the Remover out the door within that same format.


Don't worry about it! Just run the installer and the Remover will run. Keep the .dmg file if you would like to run it again in the future. This is a great idea because the older Trojan horse versions of Flashback (of which there are reportedly 13 versions that don't use Java) are going to remain out in the wild on the Internet.


Please refer back to my previous article for details about how to avoid being infected with Trojan horse malware, along with other security rules and tips:

The Rules of Computing: Keeping Your Mac Secure

The Numbers:


Adding up all the Macs infected with ALL the variations of the Flashback malware, apparently well over 600,000 Macs were affected:

Kaspersky Lab Confirms Flashfake / Flashback Botnet Infected more than 600,000 Mac OS X Computers, Describes Ramifications and Remedies

After Apple's three Java updates, the last of which included the Remover, the number dropped to half, less than 300,000 infected Macs:

Apple releases Flashback removal tool, infections drop to 270,000

Who's left in the Flashback botnet?

1) Users with Mac OS X 10.6 or 10.7 with Java installed who have not run the most recent updater or Apple's separate Flashback Malware Remover.

2) Users with Mac OS X 10.7 who never installed Java and have not yet run Apple's Flashback Malware Remover.

3) Anyone using Mac OS X 10.5 on Intel Macs. From the data of which I am aware, the Flashback malware code is directly ONLY at Intel Macs, making PPC Macs immune. It is not clear whether there has been infection of Mac OS X 10.4 Intel Macs. However, I continue to suspect there have. The Java security hole exploited by Malware.OSX.Flashback.N, the latest version (according to Intego) is apparently present in the last Java update for that version of Mac OS X.

Kaspersky has provided a web page where you can check if your specific Mac was infected with Flashback. However, I can't recommend it as the page requires you to enter your Mac's hardware UUID (Universally Unique Identifier). That's a bit like giving away your social security number and could be used by hackers to fake being you on the Internet. I suggest you only give it away to people you know and trust. Therefore, I'm not going to link Kaspersky's Flashback infection checking page here. If you'd like to use it, go digging around at the Kaspersky.com website.

Is this the time to buy Mac Anti-Malware software?

(Often wrongly called 'Anti-Virus' software). 

Probably not, unless you are dealing with the 'LUSER Factor' or unless you have an Intel Mac with Mac OS X 10.5 or 10.4. Even then, I suggest you first download and use Mark Allan's ClamXav software. It's FREE. My Mac Security friends and I work to keep the ClamAV open source project up-to-date with the latest Mac malware definitions. Install it, update its malware definitions and have it scan your entire boot drive.

There are also a number of free scanner versions of commercial anti-malware apps. I'd suggest checking out Sophos Free Anti-Virus for Mac. (I can no longer recommend the free PC Tools iAntiVirus app, which is drastically out-of-date).

If you'd like to buy the best Anti-Malware program, I continue to recommend Intego's VirusBarrier. They have a 30 trial version. I own it, use it and like it. It ships with excellent bells and whistles including its own firewall, Internet website protection, good background scanning that doesn't eat your CPU, and its own reverse firewall (similar to the renowned Little Snitch software). The only drawback is the yearly fee for malware definitions. I pay it and don't mind.

I have friends who like F-Secure Anti-Virus. They offer free online tools and a 30 day free trial. (Use the 'campaign code' on their AV page). The only reason I avoid F-Secure is that they are FUD mongers, attempting to scare Mac users with exaggerated reports about Mac malware. I don't deal with that.

Sophos is the best if you are running a small business or enterprise network of Macs. They also offer a free trial. I also like their free Sophos Security Monitor app for iOS devices. It provides timely computer security information.

The other anti-malware providers can be anywhere from OK to total CRAP. The crap includes (IMHO of course) anything from ZeoBIT and Symantec. IOW: Run away from MacKeeper and Norton Anti-Virus. 


Coming Up:


Over at my MacSmarticles blog, I will be posting an article about ZeoBIT paying their users to bombard Mac software review sites, a grotesque abuse of marketing.

Here at the Mac-Security blog, I will be providing a list of my favorite Mac security information sources.

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New: Trojan.OSX.BASH/QHost.WB.A, Posing as FlashPlayer.pkg Installer (heehee!)

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F-Secure has posted news about a new Trojan horse for Mac OS X. It is currently being called "BASH/QHost.WB". Using the standard malware naming system, the official name should be Trojan.OSX.BASH/QHost.WB.A. So far I am unaware of why it is being given a 3-part name. Most likely there will be the usual proliferation of other names across the anti-malware community before a final name is established.

F-Secure's report is well documented and worth reading here:

Trojan: BASH/QHost.WB

Why I'm laughing, heehee: Of all the software to fake for Mac OS X, it is HILARIOUS that these malware rats chose the Adobe FlashPlayer installer. Is there any more hated software for Mac OS X than Adobe Flash?! Oops. I don't see this Trojan becoming very proliferated. But there are always victims, so it is worth documenting what this thing does.

So far there is no documentation as to where the Trojan is found. As usual, double-check the source of ALL your software. NEVER install anything you've been sent or randomly picked up off the net without verifying it as legitimate. Obviously, the safest place to pick up the Adobe FlashPlayer software is directly from Adobe. Also keep in mind that Adobe FlashPlayer has historically been found to be profoundly insecure. Be absolutely certain you are installing the most recent version of FlashPlayer and check Adobe at least once a month for security updates.

When installing the fake FlashPlayer.pkg file, it looks like Apple's standard installer, fooling you that it is legitimate.

After installation, Trojan.OSX.BASH/QHost.WB.A takes over your 'hosts' file and damages it to dump your web browsers to a phishing site located in the Netherlands. The malware can easily damage the hosts file for further fake forwarding in the future. (Say that 10 times!). The Mac OS X hosts file is located here:

/private/etc/hosts

You can read about the purpose of the hosts file here:

Hosts (file) @ Wikipedia

The current version hijacks a series of Google web addresses. If you read F-Secure's notes you'll see that there are detectable differences between the real Google pages and the fake phishing pages.

Using the phishing site results in bogus search results. Clicking on the result URLs only returns you back to the phishing site. Meanwhile, however, the bogus site nails your browser with a series of pop-up pages which it grabs from a nefarious remote server.

At this time, the pop-up remote server is not providing any information to the phishing site. Possibly, this is a prototype malware being used either for demonstration purposes or to prove a hacking method to the hacking community. No doubt we will know more about the situation in the near future.

Most likely, Apple will be integrating a signature for Trojan.OSX.BASH/QHost.WB.A into their XProtect anti-malware system in Mac OS X 10.6 and 10.7. At the moment of my posting this article, Apple has not yet updated their XProtect.plist file.

Share and Enjoy!

:-Derek

Multiple Symantec Software Vulnerabilities Found

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This isn't so much a useful article as a thumb in the eye of my least favorite anti-Mac security FUD monger, Symantec. Have an *evil laugh* along with me if you like:

Digging around at the F-Secure site tonight I happened up on this article from a few days back:

Symantec Brightmail Gateway Control Center Multiple Vulnerabilities

Summary

Some vulnerabilities have been reported in Symantec Brightmail Gateway, which can be exploited by malicious people to conduct cross-site scripting attacks and by malicious users to bypass certain security restrictions.

Detailed Description

Some vulnerabilities have been reported in Symantec Brightmail Gateway, which can be exploited by malicious people to conduct cross-site scripting attacks and by malicious users to bypass certain security restrictions.

1) Certain unspecified input passed to the Control Center is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

2) An error when processing unspecified console functions can be exploited by a Control Center user to gain administrative privileges.

The vulnerabilities are reported in versions prior to 8.0.1.

The vulnerabilities were discovered by Secunia.

They were NOT discovered by Symantec.

So next time Symantec strike one of their Overlords Of Security poses, just laugh at them.

;-D
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