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

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15
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4answers
80k views

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 ...
37
votes
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 ...
10
votes
4answers
4k views

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
votes
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?
131
votes
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, ...
16
votes
6answers
9k views

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?
49
votes
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 ...
27
votes
4answers
59k views

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 ...
20
votes
8answers
11k views

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 ...
16
votes
4answers
2k views

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 ...
67
votes
6answers
37k 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 ...
50
votes
8answers
13k views

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 ...
11
votes
2answers
25k views

Advice on what to do after being hacked? [duplicate]

After running a system scan earlier today, I found that my computer had been infected by a trojan horse. My reason for running the scan was because Windows kept shutting down and then recovering. ...
3
votes
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 ...
23
votes
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
votes
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 ...
8
votes
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?
5
votes
2answers
552 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
votes
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 ...
61
votes
5answers
17k 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?
36
votes
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? ...
27
votes
4answers
2k views

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 ...
10
votes
6answers
50k views

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. ...
10
votes
3answers
3k views

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
votes
2answers
745 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. ...
6
votes
4answers
1k views

What are these URLs in my browsers?

I was testing my Node.JS application. When I opened my app using Chrome and Mozilla, I saw these JS files included in every page I browse. They appear in all browsers I use (Firefox, Chrome). ...
15
votes
3answers
10k views

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?
6
votes
3answers
2k views

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?
4
votes
3answers
6k views

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 ...
3
votes
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 ...
0
votes
3answers
625 views

Removing a Redirect Virus from Fedora Linux

Despite several attempts listed below certain websites are getting redirected to a certain ad website automatically, out of the blue on linux. When some website starts redirecting to this ad website ...
139
votes
8answers
16k views

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 ...
85
votes
2answers
16k 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 ...
36
votes
7answers
199k views

How can I watch porn, safely, and not get a virus? (and not infect corporate data also)

I'm part of a small office in the middle of nowhere, and we just got absorbed into a large mega corporation. Sometimes we watch porn, at the office, on company computers, using the company ...
37
votes
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, ...
17
votes
2answers
872 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 ...
20
votes
2answers
5k views

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?
19
votes
7answers
2k views

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 ...
20
votes
3answers
4k views

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 ...
18
votes
7answers
1k views

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
votes
2answers
484 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 ...
15
votes
7answers
10k views

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 ...
12
votes
5answers
1k views

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
votes
5answers
328 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 ...
9
votes
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 ...
9
votes
7answers
18k views

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 ...
5
votes
3answers
4k views

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
votes
2answers
233 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 ...
3
votes
2answers
288 views

I ran a virus on a PC. What should be the next steps?

I wanted to remove a probably malicious executable, but instead inadvertently double-clicked on it while using an account with administrative privileges. Nothing visible happened during a few seconds, ...
6
votes
3answers
434 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 ...