A computer virus is a program or piece of code that tends to be malicious and is loaded onto your computer without your knowledge and runs against your wishes.

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Is it safe to serve any user uploaded file under only white-listed MIME content types?

Let's say I develop an application that, Allows any user to upload a file of only white listed mime content type and extensions (word and pdf). Serves those files with the allowed extension and ...
17
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4answers
5k views

What is the corrupted image vulnerability? How does it work?

What exactly happens when someone injects malicious binary code into an image file (on Windows)? How is that done?
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2answers
16k views

What malicious things can happen when clicking on links in email?

I've received a spam from one of my friends (well I'm sure he didn't send it). so there's this link, and i'd thought what exactly would be the implications of clicking the link (i've not clicked it ...
133
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5answers
16k views

How can USB sticks be dangerous?

We all know the story of the USB drive left outside a power plant which was found by a worker and inserted into a computer to see the contents which then allowed a hack to ensue. Here is my question, ...
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8answers
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Can malware be attached to an image?

I have a small number of employees who use a company computer but these people aren't very tech savvy. They use an email client and a messaging client. I'm pretty sure they wouldn't click on .exe or ....
49
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6answers
10k views

Virus Encoded in Video

So I'm not familiar at all with IT Security, but I'm a bit curious about something. I was watching a TV show and at one point, a virus spreads through an office. They investigate and find out that the ...
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4answers
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How is a worm different from a virus?

In spite of various online articles, I'm a bit unclear on the distinction between a "worm" and a "virus". Two related questions-- Is there a useful and clear distinction here or no? If so, what is ...
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4answers
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CryptoWall 3 - how to prevent and how to decrypt?

My father's computer is now infected with CryptoWall 3, according to the link below. http://www.bleepingcomputer.com/virus-removal/cryptowall-ransomware-information#CryptoWall Is there a way to ...
6
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8answers
324 views

Difference between virus and trojan?

To my current understanding: A virus is a program that does not self replicate and relies on the host file being spread. It has malicious intent. A trojan is a program that is run by deceiving the ...
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4answers
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How to inject executable, malicious code into PDF, JPEG, MP3, etc.?

I wanted to know if its generally possible to inject executable code into files like PDFs or JPEGs etc., or must there be some kind of security hole in the application? And if so, how would one do ...
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8answers
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Should I get an antivirus for my Mac?

There are some people saying that people should use an antivirus software on Mac. And there are thousands of people claiming that Macs don't get viruses (under this term I mean spyware / malware as ...
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6answers
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Finding a specific malware sample for malware analysis purposes

I wish to analyze the changes made by a specific virus. For example, Win32.Sality. Where can I get the sample of this, or other similar, malware for testing?
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3answers
1k views

Is it possible for a virus or unknown program to automatically start up a webcam

How can I secure my computer more, knowing these days that there are many websites, especially ones where you don't have to even click before a virus is downloaded straight to your hard-drive. I ...
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6answers
39k views

Should I get an antivirus for Ubuntu?

Considering the recent thread regarding anti-virus for the Mac I wonder how many of the arguments put forth are relevant today to Linux systems, specifically Ubuntu. There are no known Ubuntu ...
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4answers
7k views

Are popular porn sites more likely to be infected with malware?

I'm trying to help my friend understand this because he believes that since a site is very popular, that it's less likely to infect its viewers because of its security! Is a popular site less likely ...
8
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3answers
4k views

Viruses on video cards?

Steve Gibson of Security Now fame claims that viruses can attack a video card and infect it. I assume that he means it can infect the Video BIOS. However I'm skeptical. BIOSes are so numerous and ...
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2answers
557 views

How might an email do damage merely by being opened?

E.g. http://www.dailymail.co.uk/sciencetech/article-2094982/Threat-new-virus-infected-emails-PC-DONT-open-attachments.html?ito=feeds-newsxml Assuming that the user clicks no links and opens no ...
129
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11answers
16k views

Can a computer virus be stored somewhere else than on the hard drive?

Are there viruses that have managed to hide themselves somewhere other than on the hard drive? Like CPU cache or on the motherboard? Is it even possible? Say I get a virus, so I get rid of the HDD ...
89
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2answers
20k views

Can a rogue .wmv file “hijack” Windows Media Player?

I've downloaded a .wmv file using P2P. Attempting to play it with Media Player Classic (K-Lite Codec Pack) only gave me a green square in the playback window: I noticed that the video came with a ...
61
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5answers
18k views

Can my mouse have virus and infect other machines?

This is my mouse. I used it with my old computer which was full of viruses. If I use this mouse for my new PC, can my new computer be infected from my mouse?
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5answers
4k views

Can malicious code trigger without the user executing or opening the file?

If a file is downloaded from the Internet, and saved on disk, but is not opened by a user (if we keep autorun off), are there any chances that malicious code (e.g. a virus) in the file could trigger? ...
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6answers
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Scanning for files than have been encrypted by CryptoLocker

I am just asking in case someone has already done the analysis. A customer has a large set of network drives that were mapped to a CryptoLocker infected machine. The infection itself has been treated. ...
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3answers
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Am I protected from USB autorun malware on Windows 7?

As far as I know, the autorun.inf problem (the possibility of automatically executing code when a USB stick is plugged in) was solved through Windows Updates for XP, and on 7 it is no longer possible ...
8
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2answers
770 views

What is a Flash drive by download?

I've seen many people saying how some sites can infect your computer without actually clicking anything. They said that it was a "Flash Drive By" and it would use flash to download a file of any kind. ...
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5answers
1k views

Is disabling auto-run enough to protect against malicious code from removable media automatically infecting a machine?

If I block auto-run on a windows machine, is this enough to protect it from malicious code (assuming I don't run any files manually)? Or are there known vulnerabilities that may cause infection?
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3answers
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Can malware physically damage a hard drive?

I recently responded to an incident of supposed malware infection. The symptoms were simply, "My computer freezes at random times." The response ended with replacement of the physical hard drive and ...
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Can Cryptolocker (Or Other Ransomware) Encrypt Files That Are Already Encrypted?

If you have already encrypted files, are they still vulnerable to being encrypted a second time by a program like Cryptolocker, or would this protect them?
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3answers
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Is it possible to catch a virus on my LAN without clicking on anything?

My unpatched PC running Windows is connected to a network which contains other "infected" computers, can I get infected by viruses without any interaction on my part?
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5answers
2k views

How can I know if my PC is getting infected?

I have installed an antivirus, but as no antivirus is perfect, what can I do to diagnose if my PC is getting infected? For example, keeping a close eye on what programs and tasks run when I turn my ...
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3answers
147 views

Is it possible for a virus to be downloaded unknowingly and run when a website is opened?

Usually, the only time I see viruses happen is when someone mistakenly runs an infected file. But could one also be infected by just visiting a website?
139
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8answers
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What should you do if you catch ransomware mid-operation?

You boot up your computer one day and while using it you notice that your drive is unusually busy. You check the System Monitor and notice that an unknown process is using the CPU and both reading and ...
37
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7answers
7k views

Does a virus need to be clicked on to function?

Can a virus infect my Windows XP operating system by its mere presence? I mean, if I copy/paste a virus on my computer and I never click on it, will it infect my computer or will it remain dormant, ...
21
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2answers
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How does a crypter for bypassing antivirus detection work?

I am talking about crypters used to encrypt files like viruses and keyloggers for the sole purpose of bypassing antivirus detection. How do they work?
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2answers
959 views

Is there a real possibility of getting malware by “drive-by”?

I know malware can be gotten by downloading and running stuff, but is there a real possibility of just viewing a webpage or clicking a link and getting one? Assuming using only Firefox / Chrome and ...
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6answers
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Why do malware creators use such clever technologies for such silly purposes?

Some days ago I got infected by a malware, probably something new and very clever, as it went in unstopped and no scanning tool was able to detect it afterwards (see this question). It was a two-...
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4answers
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Are anti-virus companies companies regularly committing software piracy?

As Mikko Hypponen highlighted in a recent tweet, anti-Virus companies collect and store both samples of malicious software and samples of legitimate software: This got me to thinking, what ...
20
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3answers
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How can I tell if I have the citadel virus without downloading an antivirus?

I recently received an e-mail from Virgin Media indicating that I might have the Citadel virus. It obviously sounds like a fake e-mail, but I am almost certain it is genuine, as they had my name and ...
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7answers
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How to deal with a person who gets easily fooled by internet and mail scams?

alternative title: How to deal with a person who has gotten paranoid and doesn't want to go online anymore? A person, who has over the years been scammed many times, by bad spam/fraud emails, and ...
17
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2answers
568 views

Do the most common ransomware programs delete the original files as they go, or in a big bulk delete at the very end?

I'm talking about the most common varieties like Cryptolocker, Cryptowall, Torrentlocker, KeRanger, RSA4096, etc. (There is not necessarily a need to answer for all of these, one or two may do.) If ...
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7answers
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how to protect my USB stick from Viruses

I repair a lot of computers with viruses, malware, and what not, and I have one problem that I am struggling to find a solution for. Whenever I connect my USB stick that has the tools I need for the ...
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5answers
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Detection and analysis of unknown malware

Suppose I have a binary which is suspicious. How can I determine whether it is malicious, and if it is, reverse-engineer how it works and what it does? For example, maybe using static analysis? Are ...
11
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5answers
331 views

Security of root terminal (su -) when logged into X

I often log into X as normal user (of course), open terminal and switch to root: su - I have then a terminal owned by user but effectively with root privileges. Are there any security issues in ...
10
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6answers
1k views

What is preventing the widespread common use of MAC-type systems?

Overall question What is preventing the uptake of MAC systems such as SELinux/AppArmor in corporate and desktop computing environments? Why don't you think it isn't already widespread? I do not ...
10
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7answers
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How can I prevent viruses/malware from infecting my flash drive?

I've a pen drive that I carry to the college lab . It seems all the systems in lab is infected. I need to be able to write to the drive, so I can't simply write protect it. Everytime I insert a ...
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3answers
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Self-Executing Files

I've always been curious about understanding how virus carry out their activities. For that reason, I've read a lot of books and articles about different types of viruses and the way they operate in a ...
2
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2answers
242 views

Determining safety of Android APK executable that requires root

On my request, a developer gave me a new version of his Android app to test. The app requires root permissions. I do not know the developer personally. I have no specific reasons to trust or ...
7
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3answers
449 views

How safe are copies of Firefox that are on various Mozilla mirror sites?

If I end up downloading a .dmg or .exe (depending on OS) installer from some mirror site, how can I be sure that a virus or trojan or spyware has not been added? I don't see any mechanism for ...
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1answer
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How antivirus companies create virus defnitions for new outbreaks

This question quite amazes me. I dont understand how antivirus companies get info about the latest viruses. have they installed some kind of filters to monitor the internet traffic ? Or they are ...
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4answers
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Virus scanner on server

I see lots of people claim virus scanners are unnecessary on a linux server. But if this server accepts files uploaded from users (and lets others download them), does it become worth it to scan the ...
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2answers
900 views

How to get rid of an Ad bot?

The issue started due to setting up a proxy server on a PC connected to my network. I then realized that all of my devices that connected to the network, including PCs and phones, are all infected by ...