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51

Yes, that's possible. The malware probably wouldn't be embedded in the video itself, but the video file would be specially crafted to exploit a vulnerability in the codec or media player, to gain code execution. The exploit would then download a file and run it, infecting the machine. These types of exploits have been common amongst popular document ...


44

The common reasons for links in spam email are: verification that your email address is valid and that it is read which makes the email address more valuable for address brokers (the link needs to have some individual part, that can be a number, but it can also just be unique word from the dictionary). This kind of link may be labeld "unsubscribe". the ...


43

A virus can't do anything by simply being present on your system as data. A virus is just a program, it must be executed by something. The trick is that that something does not have to be you clicking it. Computers do many things automatically without your attention. They accept requests for file transfers, remote desktop, provide details about their ...


41

It depends on the file format. Executables do not run themselves, unless some clever trick is employed (autorun.inf and .lnk were popular techniques a while ago). Nevertheless, MS11-006 demonstrates that clicking on an infected file is not always necessary (this exploit triggered when a thumbnail of the infected document was rendered by the system, for ...


39

There is no clear evidence that third party anti-malware security software (AV software) is more effective than Apple's own security solutions to protect Macs. Rich Mogull on the Mac TidBITS blog explains: Far less malware exists for Macs, but even there we see limited effectiveness across tools. For example, in a recent test by Thomas Reed, even the ...


34

The same way you shop online without getting your CC details stolen. Buy from reliable vendors that have established reputations as legitimate businesses. Don't go places where they are trying to bait people in to generate bot nets and steal personal info. If a deal is too good to be true, chances are good that it is. That said, security also involves ...


28

You can install an antivirus if you want. It should not hurt your machine, but don't expect much protection for your system and don't consider yourself entirely safe. The efficacy of antivirus software is very relative, and they're mostly in use to avoid propagate old malware especially if you have Windows machines in your ecosystem. You should expect a ...


27

Sure. In Cohen's famous result, he says that a perfect virus detector should emit an alarm if and only if the input program can ever act like a virus (i.e., infect your machine and do damage). Consider the following program: f(); infect_and_do_damage(); where f() is some harmless function, and infect_and_do_damage() is a viral payload that infects your ...


26

The other answers mostly talk about attaching arbitrary code to images via steganographic techniques, but that's not very interesting since it requires that the user be complicit in extracting and executing that. The user could just execute malicious code directly if that's their goal. Really you're interested in whether there's a possibility of ...


26

This is a little long but this exact argument has been rehashed for the last 14 years. I want to put it to bed. I worked for Apple Tech support from 1992-2001 and have been an Apple developer since. So, I have a very good historical view of Apple ecosystem malware security. My conclusion? 3rd party anti-malware software on the Mac is unnecessary and as ...


25

The website seem to be be only checking the User-Agent. I tried the following wget --user-agent="Mozilla/5.0 (Windows NT 5.2; rv:2.0.1) Gecko/20100101 Firefox/4.0.1" "http://tfdesignsandpcrepair.com/dinwnle.php?get_info=ss00_323" -O file.zip and it seems to be working One possibility is that you might have tried so many times without a valid User-Agent ...


23

Despite the common wisdom, I would not recommend running anti-virus for two reasons: Anti-virus does not really work. Though it might catch trivial or well-known viruses, it mostly just gives you a false sense of security. Anti-virus can cause problems. In order to function, anti-virus programs have to situate themselves quite low on the computer ...


23

No, a virus does not need to be clicked on or accessed by the user directly to infect a system. All the virus laden file needs to do is take advantage of a vulnerability in the program that is accessing it. Examples in Windows XP Security Bulletin MS11-006 documents a bug in the way thumbnails were produced by windows explorer to trick it into running ...


22

Some formats can be called inherently insecure due to their complexity and their history of use as attack vectors. Adobe PDF and MS Office files come to mind. Any kind of binary executable is certainly problematic unless sandboxing is deployed. But in general it depends on the application that is used to open the file, not the file itself. Even simple ...


20

Macs do get viruses, the main reason why there were historically so few viruses around for Mac is because their market share was so small. When someone writes a virus, most of the time they want to infect as many targets as possible. So 10 years ago this would result in almost only Windows viruses since they had such large market share. Recently, however, ...


18

You can lookup vulnerabilities at http://cve.mitre.org/. "CVE is a dictionary of publicly known information security vulnerabilities and exposures." A rough seearch of Firefox, returns 888 Chrome, returns 729 Flash, returns 371 Further filtering of the severity of these would need to be done, but this gives an upper bound of found vulnerabilities. ...


18

Theoretically, no, an infected machine cannot be trusted anymore. In practice, wiping out the hard disk (or just removing it and inserting a new one) is often sufficient, although some virus have been known to reflash part of the BIOS, for pure wanton devastation, or to make the virus resistant to disk formatting. Some motherboards will not allow reflashing ...


17

Firstly, there is no guarantee you'll even be able to run a VM inside a VM. It may seem obvious but it is by no means certain it will even work. This is because VM's may rely on virtualization features of your hardware which are not exposed inside the VM itself. Secondly, why two, why not three, four, five, etc... There is such a thing as overkill security. ...


17

The goal of most malware is to remain active as long as possible. The longer it can collect keystrokes, participate in DDoS attacks, redirect search results, send spam emails, shows popup ads, etc., the more profitable it is for the creator. To reach this goal, it has to be undetected. If a piece of malware infects a machine twice, it may leave the machine ...


17

It all depends on the person; but a good first step would be to change their default browser to Chrome or Firefox - install AdBlock Plus (http://adblockplus.org/, or similar) and Ghostery (http://www.ghostery.com/) in their browser, and a decent anti-virus (Microsoft Security Essentials (http://www.microsoft.com/mse) should be fine, and since it's free - you ...


17

I think it's generally popular sites, not just porn sites. However there might be some reasons why pornsites tend to attract more malware. Mostly malware originates from dodgy advertisement platforms. Because the morality of porn is often debated and not accepted in every culture, a lot of larger advertisement websites, such as Google Ads, do not allow ...


17

Same way you can watch any other other website safely: Use a modern and updated browser. Do not download anything from a source you don't trust. Do not run media plugins like Flash and Java by default. Do not run media plugins like Flash and Java on a site that you don't trust, at all. Do not under any circumstance install or run Adobe Reader, it is ...


16

In theory, any format that requires complicated processing or allows embedding of other formats (especially Flash) can be dangerous. The most relevant issues right now are however: Any Microsoft Office files (not so much because of Office vulnerabilities but because these files can embed Flash and exploit its vulnerabilities) PDF files Obviously, any files ...


16

Set up an intermediate Tor VM, one side connected to outside, the other to a dedicated virtual network. Set up a porn watching VM (with tissues included), connected to the Tor VM via the dedicated network. After the VM #2 is fully set up, power it down and take a snapshot. Power it up. ??? After you've enjoyed all the great educational videos, power the VM ...


15

The difference is mostly a matter of historical tradition. Biologically, a virus is a piece of RNA. RNA is an intermediary vessel for genetic code, which temporarily duplicates a piece of the DNA (the permanent storage of genetic information in a cell). RNA then goes through some "engines" which can duplicate it and/or convert it into proteins (genetic code ...


15

Various reasons: Attacker is often not the Developer - Developers of malware sell the packages to anyone - the payload will be then defined by the attacker. Some attackers want to be stealthy - some don't, in fact some delight in being obvious and notorious. Practice - developing techniques Apathy/Ignorance - end users are really no good at fixing ...


14

I'll answer in the form of an anecdote. Back in 2003, I was working in tech support for a Mac-based organisation. We were essentially a government contractor and, as such, nearly all our money came from sending Microsoft Word documents to the government to document what we had done and what we should be paid for. Someone managed to bring a Word macro virus ...


13

Detection for a piece of malware is never removed from a mainstream AV. Detection for old or rare malware is not removed mainly because AV benchmarks and clients seeing one AV missing detection while the others have it. Let's say a signature is added for "Malw" malware but then the persistent malware writer makes subtle changes to avoid that specific ...


13

I have a couple of questions here: Are the files fine when in the lab? And only become 'infected' when you move them to your USB drive? Are you certain the USB stick is clean? Does the USB stick have software on it which is supposed to write files as exe's (some versions do this if encryption is enabled) The reason I ask is that it could be an issue you ...



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