twitter ios iconWe've been following for some time the story of the Flashback trojan that has been targeting Mac users by masquerading as a Flash Player installer but which has also been evolving to include increasingly sophisticated tactics for infecting users' computers.

Antivirus firm Intego now reports that Flashback's creators are using an interesting new tactic for communicating with machines infected by the trojan: Twitter. According to the report, Flashback is programmed to search Twitter for Tweets containing a unique 12-digit code that changes daily, with the malware's authors being able to issue commands to infected computers by posting from any number of Twitter accounts simply by including the appropriate code as a hashtag.

These hashtags aren’t as simple as, say, #Flashback or #MacMalwareMaster, but are seemingly random strings of characters that change each day. Intego’s malware research team cracked the 128-bit RC4 encryption used for Flashback’s code and discovered the keys to this system.

The hashtags are made up of twelve characters. There are four characters for the day, four characters for the month, and four characters for the year. [...]

So, for today, March 5, 2012, the hashtag would be #pepbyfadxeoa.

Intego is monitoring Twitter to look for any commands being issued using the hashtag codes, also noting that Flashback uses a number of different user agent strings in its web queries looking for the Twitter contacts, seeking to avoid detection and removal.

Top Rated Comments

GGJstudios Avatar
181 months ago
I just upgraded my gfs flashplayer last week ... What are the chances that it's this Trojan ?? How can I check?
Go to your /Users/yourusername/Library/ folder and look to see if you find any of these files:
~/.MacOSX/environment.plist
~/Library/LaunchAgents/com.apple.SystemUI.plist
~/Library/Preferences/perflib
~/Library/Preferences/Preferences.dylib
~/Library/Logs/swlog
If you don't have any of these files, you're not infected.

Your Library folders are hidden by default in Lion. To get to your /Library or /Users/yourusername/Library (also known as the ~/Library) folders in Lion, Launch Finder and click Go > Go to Folder and type: /Library or ~/Library

Here's how to avoid any question:
With my flash player I'm careful. I never click on a pop-up when it tells me it's out of date.

I go to Adobe's site and update there.
This is very important:
To repeat: the vendor has provided no actual evidence that such messages are happening.
In fact, while I may have missed it, I've seen no corroborating evidence supporting the recent reports coming from Intego. I haven't seen any other security firm confirming the presence of these variations, or the variation that supposedly installs itself without user intervention, as they also claim. Until such claims are proven by other companies, I'll continue to find Intego's claims suspicious, at best.

Generally speaking, these reports by security firms are little more than thinly veiled attempts to scare users into buying their security software, which you don't need. However, such reports can be useful reminders for users to continue to practice safe computing.
[LIST=1]
* Make sure your built-in Mac firewall is enabled in System Preferences > Security > Firewall


* Uncheck "Open "safe" files after downloading" in Safari > Preferences > General


* Uncheck "Enable Java" in Safari > Preferences > Security. Leave this unchecked until you visit a trusted site that requires Java, then re-enable only for your visit to that site. (This is not to be confused with JavaScript, which you should leave enabled.)


* Check your DNS settings by reading this (https://guides.macrumors.com/Mac_Virus/Malware_FAQ#Why_am_I_being_redirected_to_other_sites.3F).


* Be careful to only install software from trusted, reputable sites. Never install pirated software. If you're not sure about an app, ask in this forum before installing.


* Never let someone else have physical access to install anything on your Mac.


* Always keep your Mac and application software updated. Use Software Update for your Mac software. For other software, it's safer to get updates from the developer's site or from the menu item "Check for updates", rather than installing from any notification window that pops up while you're surfing the web.

That's all you need to do to keep your Mac completely free of any virus, trojan, spyware, keylogger, or other malware.

You don't need any 3rd party antivirus app to keep your Mac malware-free. Macs are not immune to malware, but no true viruses exist in the wild that can run on Mac OS X, and there never have been any since it was released over 10 years ago. You cannot infect your Mac simply by visiting a website, unzipping a file, opening an email attachment or joining a network. The only malware in the wild that can affect Mac OS X is a handful of trojans, which cannot infect your Mac unless you actively install them, and they can be easily avoided with some basic education, common sense and care in what software you install. Also, Mac OS X Snow Leopard and Lion have anti-malware protection (http://support.apple.com/kb/ht4651) built in, further reducing the need for 3rd party antivirus apps.
Mac Virus/Malware FAQ (https://guides.macrumors.com/Mac_Virus/Malware_FAQ)
Score: 8 Votes (Like | Disagree)
FloatingBones Avatar
181 months ago
The claim is interesting, but a quick search on Twitter doesn't show that #pepbyfadxeoa is actually being used by any program for anything. If the vendor's claim is true, they should be able to tell us a prior hashtag which shows actual nefarious activity.

We are still suffering from Adobe's lax attitudes for security around their products. All of the "Get Flash Player" and "Get Adobe PDF Reader" links that Adobe encouraged in the past have helped foster a lackadaisical attitude towards the clear risk of installing a trojan horse on machines. I will be happy as Flash on the WWW continues to fade into the sunset.

I think this uses twitter even if you don't use it personally, they are just using the open nature of the site as a means to communicate with the malware.
Bingo. If the trojan is actually using twitter as a conduit, it's probably using accounts that were embedded in the trojan. Blocking those would require the blocking of connections to twitter servers with something like Little Snitch (http://www.obdev.at/products/littlesnitch/index.html)
or outbound blocks in your network's firewall.

To repeat: the vendor has provided no actual evidence that such messages are happening. I see no evidence with todays hashtag.

One other note: the Twitter stream is a real cesspool these days. As far as I can tell, Twitter does nothing to automatically remove the 'bot accounts that send out Amazon Associates link-spam. They're also doing nothing to automatically censor accounts that send @mentions that spam the "adult" dating sites. Doesn't Twitter have any friends in the Valley who could help them keep the toxic pollution out of their stream?
Score: 7 Votes (Like | Disagree)
GGJstudios Avatar
181 months ago

Much like life, if you hang around in bars, you can come down with diseases.
So if you don't hang around in bars, you won't catch any diseases???
Score: 6 Votes (Like | Disagree)
FloatingBones Avatar
181 months ago
I'm always suspicious of anti-virus firms who seem to know very specific details of viruses/malware/trojans.

I'm even more suspicious when the claimed evidence doesn't pan out. To alter the slogan from that famous Wendy's commercial (//www.youtube.com/watch?v=Ug75diEyiA0):

Where's the tweets? :D
Score: 5 Votes (Like | Disagree)
mijail Avatar
181 months ago
I'm always suspicious of anti-virus firms who seem to know very specific details of viruses/malware/trojans.

Word, bro. And what about those pesky "doctors" who seem to know all about illnesses and bacteria and whatnot? Damned scientists!
(Fricking magnets, how do they work?)

----------

Then you can send a message to the hacker how dumb he was. With the same amount of work he had put into this malware he could have created an app and probably made some money.

You mean he has no bussiness plan for this?
Score: 4 Votes (Like | Disagree)
Amazing Iceman Avatar
181 months ago
Nasty!!

(I'm breaking my arm patting myself on the back for my non-involement with social media.)

I do feel bad for the majority of the world who does use social media...this is really lousy.

Much crap on social media, but a tremendous amount of good in places where free expression is only possible through Twitter, etc. It's a powerful tool for many in the world, and any sympathy I might have for certain hackers is totally absent in situations like this.

Well, don't over pad yourself. The infection doesn't come from Twitter, but from a fake Adobe Flash Installer. Twitter is only one of the many ways hackers use to communicate with the hacked Macs.
Score: 3 Votes (Like | Disagree)

Popular Stories

iPhone Top Left Hole Punch Face ID Feature Purple

iPhone 18 Pro Launching Later This Year With These 12 New Features

Thursday January 15, 2026 10:56 am PST by
While the iPhone 18 Pro and iPhone 18 Pro Max are not expected to launch for another eight months, there are already plenty of rumors about the devices. Below, we have recapped 12 features rumored for the iPhone 18 Pro models, as of January 2026: The same overall design is expected, with 6.3-inch and 6.9-inch display sizes, and a "plateau" housing three rear cameras Under-screen Face ID...
Apple MacBook Pro M4 hero

These 5 Apple Products Will Reportedly Be Upgraded With OLED Displays

Friday January 16, 2026 7:07 pm PST by
Apple plans to upgrade the iPad mini, MacBook Pro, iPad Air, iMac, and MacBook Air with OLED displays between 2026 and 2028, according to DigiTimes. Bloomberg's Mark Gurman previously reported that the iPad mini and MacBook Pro will receive an OLED display as early as this year, but he does not expect the MacBook Air to adopt the technology until 2028 at the earliest. A new iPad Air is...
2024 iPhone Boxes Feature

Apple Adjusts Trade-In Values for iPhones, Macs, and More

Thursday January 15, 2026 11:19 am PST by
Apple today updated its trade-in values for select iPhone, iPad, Mac, and Apple Watch models. Trade-ins can be completed on Apple's website, or at an Apple Store. The charts below provide an overview of Apple's current and previous trade-in values in the United States, according to the company's website. Most of the values declined slightly, but some of the Mac values increased. iPhone ...
Apple Wallet ID Illinois

Apple Plans to Expand iPhone Driver's Licenses to These 7 U.S. States

Friday January 16, 2026 12:12 pm PST by
In select U.S. states, residents can add their driver's license or state ID to the Apple Wallet app on the iPhone and Apple Watch, and then use it to display proof of identity or age at select airports and businesses, and in select apps. The feature is currently available in 13 U.S. states and Puerto Rico, and it is expected to launch in at least seven more in the future. To set up the...
iPhone Top Left Hole Punch Face ID Feature Purple

New Leak Reveals iPhone 18 Pro Display Sizes, Under-Screen Face ID, and More

Wednesday January 14, 2026 7:09 am PST by
While the iPhone 18 Pro models are still around eight months away, a leaker has shared some alleged details about the devices. In a post on Chinese social media platform Weibo this week, the account Digital Chat Station said the iPhone 18 Pro and iPhone 18 Pro Max will have the same 6.3-inch and 6.9-inch display sizes as the iPhone 17 Pro and iPhone 17 Pro Max. Consistent with previous...