0
votes
1answer
85 views

How would I know if my Apple Mac has a virus, and what can I do if I have? [closed]

I have used PCs for most of my life, and I am very aware of the fact that they can catch a variety of viruses. I have owned a MAC now for two years, and have enjoyed a pleasant (perhaps too pleasant) ...
2
votes
4answers
557 views

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 ...
1
vote
1answer
70 views

Clamav can't detect encoded virus files

I have a PHP sheller file (like c99 file) but it's Encoded ( with this functions: eval(gzinflate(base64_decode("7P3rehblahblah)) ) and the clamav virus scan can't detect it. How i can detect virus ...
4
votes
4answers
360 views

Is it worth it to get paid anti-virus software?

With the rise in cybercrime, I am slightly worried about my computer security. I have been using open sourced anti-virus AVG for years and it has been doing well. Are anti-virus software like Norton ...
0
votes
1answer
157 views

Which Antivirus Software used to remove virus Rootkit.Sirefef.Gen?

My System has affect Rootkit.Sirefef.Gen Virus. So i want to know which antivirus software is used to remove Rootkit.Sirefef.Gen virus file.
2
votes
3answers
335 views

How to keep Mac secure from viruses, malware and keyloggers?

How can I download and install software and make sure that it is not infected with viruses, malware or a keylogger? Also, I heard that Macs "don't get viruses". Is this true? Is it a good practice to ...
2
votes
2answers
216 views

A new virus with unknown function

We have detected a new virus that was sent to us by mail. The email contained a zip file which contains an executable with the same name. As a first step, we uploaded the file to virustotal, to be ...
2
votes
3answers
301 views

Is there a hash algorithm that can identify similar files or strings?

Is there a hash algorithm that will help you identify similar files or strings? For example, the hash for ABC and XBC would be similar rather than radically different as is usually the case. I know of ...
1
vote
3answers
148 views

Protecting Backups from Viruses

Currently we are using ReadyNAS by NETGEAR to hold all our images from all our machines. My question is can viruses expand from the machines and infect the NAS drive and the backups? We are using ...
0
votes
1answer
100 views

What is “KDV” in antivirus databases?

I scanned a file (virus) on VirusTotal and 3-5 antivirus labelled it as Generic.KDV.549626 Is there any central "KDV" database where all the entries related to a virus are stored?
2
votes
1answer
681 views

Windows PE file and Malwares

Trying to understand how and why any virus, malware, worm and code injections are successful after all in a Windows Portable Executable format. I was going through the PE structure documentation, ...
2
votes
2answers
120 views

If a user visited a malicious website a year ago, should we nuke from orbit to be safe?

A Microsoft Security Essentials virus scan just finished on one of our computers and it shows two potential threats in Internet Explorer's temporary internet files: Web page with Black Hole Exploit ...
3
votes
2answers
181 views

Why some antiviruses detect viruses and some not?

I am curious why some anti-viruses detect viruses and some do not. From what I found online, antiviruses parse the binary files and check the sequence of code which is malicious(exists in virus ...
0
votes
2answers
172 views

How isolated are 2 operating systems on 1 harddisk?

Lets say I have 2 windows dual booting on the same harddrive (windws 7), How isolated are they? I am thinking that there should be up to date antiviruses software on both Windows, and they should be ...
16
votes
6answers
577 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 ...
2
votes
6answers
2k views

Why do some antivirus programs find infections that others miss?

I have Avast Free antivirus on my Windows 7 PC and yesterday I used Bit Defender quick scan addons, which spotted a virus. In rechecking with Avast, it didn't pick it up. In scanning my system with ...
18
votes
3answers
858 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 ...
2
votes
3answers
117 views

How to tell what viruses are covered by your anti-virus software

One of our corporate twitter accounts recently started sending out DMs to its followers. Looking at the content of these it seems we'd become infected with Troj/Mdrop-EML. All computers on our ...
16
votes
5answers
909 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 ...
19
votes
4answers
1k 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 ...
-1
votes
2answers
6k views

Malware or buggy software gives Low Disk Space warning

Since a few days, I am getting an alert that in my c drive disk space is low. When I verified, free space in my c drive was decreasing hour by hour and there was a stage when it simply said that 0 mb ...
3
votes
4answers
323 views

Has any virus attempted to compromise the anti-virus database?

I was using an old version of Norton Anti Virus and the Live Update wouldn't run. The solution was to rename a file. This got me thinking if a virus could replace an anti-virus database with it's own ...
21
votes
2answers
647 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 ...
3
votes
5answers
1k 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
2answers
222 views

How could an AV detect a virus that has a chance of not decrypting itself?

If I understand this correctly there is a chance the virus may not decrypt itself at all. How could an AV catch this? In some cases, the decryptor may start with a header whose intent is not ...
-1
votes
1answer
120 views

Would this be plausible for a metamorphic virus? Not repeatedly infecting same system

Would this be plausible for a metamorphic virus? When a new generation (for lack of better word) is created it would hard code a random file name, that would be checked to see if the system was ...
3
votes
3answers
478 views

How do polymorphic/metamorphic/self-encrypting/self-changing file infectors know if they have infected a file or not?

If a virus rewrites itself for each infection how would it know if it has infected a file or not? If it keeps infecting the same file soon the whole file structure will be corrupt. For example how ...
2
votes
2answers
179 views

How do viruses know if they have already infected a system or done something?

I know some viruses repeat the same actions over and over again with no break, thus grinding the network to a halt. But others "take a break" from there repetitive actions. For example Nimda ...
3
votes
2answers
377 views

Why does Antivirus Softwares have an Issue with EXE Packers

Im trying to pack an Executable using an Exe Packer like UPX.I packed and checked the File with VirusTotal.com.Here some 9 Antivirus Products say its a Virus actually its a harmless exe.I think the AV ...
2
votes
3answers
1k views

Do I have a virus on my hosted site?

A few weeks ago I hired an outsourcer from India to build for me a very simple PHP site. I bought PHP hosting and a domain name, and I gave him all the credentials together with the specification of ...
5
votes
1answer
329 views

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 ...
13
votes
4answers
966 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 ...
3
votes
4answers
316 views

What is the purpose of EICAR?

For as long as can remember, EICAR has been used to test for the presence of Antivirus systems in email, the file system, or other places. Sometimes the AV solution is so far out of date, that its ...
18
votes
2answers
3k 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?