Questions tagged [antivirus]

Antivirus or anti-virus software is used to prevent, detect, and remove malware, including but not limited to computer viruses, computer worm, trojan horses, spyware and adware.

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170
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10answers
27k views

Help! My home PC has been infected by a virus! What do I do now?

This is an attempt to ask a canonical question as discussed in this old meta post. The goal is to create something helpful that can be used as a duplicate when non experts ask about virus infections. ...
161
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10answers
20k views

How do you explain the necessity of “nuke it from orbit” to management and users?

When a machine has been infected with malware, most of us here immediately identify the appropriate action as "nuke it from orbit" - i.e. wipe the system and start over. Unfortunately, this is often ...
21
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8answers
3k views

Are signature based antivirus or antimalware effective?

Are signature based antivirus or antimalware solutions effective? Has the battle been lost against the ever increasing amount of malware, particularly rootkits, that are in the wild?
38
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6answers
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Can malware be dangerous even when quarantined?

I am reading a book on network security and when talking about user confusion it writes: "It is not uncommon for a user to be asked security questions such as Is it safe to quarantine this ...
53
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8answers
15k 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 ...
36
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3answers
43k views

Why is 'avast! Web/Mail Shield Root' listed as CA for google.com?

I just noticed something weird in my browser: the certificate for www.google.com has been issued by avast! Web/Mail Shield Root. Should I be worried? I am using avast! Antivirus so it's probably a ...
20
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6answers
4k 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 ...
161
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14answers
17k views

What is the safest way to deal with loads of incoming PDF files, some of which could potentially be malicious?

As an investigative journalist I receive each day dozens of messages, many of which contain PDF documents. But I'm worried about some of the potentially malicious consequences of blindly opening them ...
112
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9answers
19k views

Alternatives to anti-virus for keeping oneself safe

I have read a lot of articles that talk about how using an AV is less safe than not having one for more intermediate PC users who are careful with what they click and download. For example, here are ...
91
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7answers
51k 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 desktop ...
23
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2answers
8k views

How do anti-virus apps for Android work?

There seems to be a lot of anti-virus apps for Android. On a desktop or server an anti-virus must run with super-user privileges, however I am pretty sure these mobile anti-viruses are running as an ...
17
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4answers
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How AV software makes sure quarantined files never get executed? [duplicate]

This Super User question made me ask, is it really a good idea to keep files in quarantine, when you don't know what they are yet? For what I know there are more or less 2 steps that need to be ...
6
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4answers
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What is nuke it from orbit? [duplicate]

I was reading this Windows 2003 Enterprise infected by Conficker; post-infection problems continue And they talk about nuking it from orbit (which apparently means wiping out the system and starting ...
39
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5answers
53k views

How to scan a PDF for malware? [closed]

Can anyone suggest an automated tool to scan a PDF file to determine whether it might contain malware or other "bad stuff"? Or, alternatively, assigns a risk level to the PDF? I would prefer a free ...
47
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2answers
19k views

How do antiviruses scan for thousands of malware signatures in a short time?

Most antiviruses have hundreds of thousands or even millions of malware signatures and yet they scan many files in a reasonable short time with high detection rates. Even real-time scanners doesn't ...
23
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3answers
7k 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?
44
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8answers
24k views

Are two anti-virus better than one in protecting your computer?

A century old adage: The more the merrier. In general, does this adage hold true in regards to the number of anti-virus software you should have on your PC? Are there any limits before it actually ...
7
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3answers
4k views

Metasploit Meterpreter Persistence Script Alternatives

These days I am testing various type of client hacking techniques, and in all scenarios I am using Meterpreter/reverse_tcp as payload. Now I can bypass Anti-Virus and Firewalls easily, but when i run ...
9
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1answer
1k views

How does one properly check foreign USB Drives before getting them in your Network? Is the presented approach considered “safe”?

Current Situation: I´m currently employed at an Hospital and with rising danger of ransomware etc. spread by usb drives we decided to block all USB-Ports (roundabout 600 Clients/Windows only) via ...
10
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2answers
6k views

Antivirus for scanning anonymous file uploads

Since I have no experience with AV solutions on Unix-like environments, I would need help with suggestions on something that can be suitable for scanning files that are uploaded by anonymous users ...
8
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3answers
25k views

What is the precise difference between a signature based vs behavior based antivirus?

I do not understand very well the difference between signature based vs behavior based antiviruses. Please clarify the distinction between the two.
26
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3answers
15k views

Metasploit Meterpreter alternatives

These days I am testing various type of client hacking techniques, but in all scenarios I am using Meterpreter variations as payload. Now I can bypass Anti-Virus and Firewalls easily, but Symantec ...
77
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15answers
17k views

How to write an email regarding IT Security that will be read, and not ignored by the end user?

I've observed that several of our users are ignoring messages sent from IT Security managers, and also the system generated "You just sent a virus" notifications. The problem seems to be among people ...
13
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2answers
6k views

Custom Metasploit payload with UAC bypass

The machine I am attacking has anti-virus installed. I have managed to use Veil Framework in order to create an initial reverse shell payload that is undetected by the AV. However, UAC is enabled on ...
10
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2answers
1k views

AV detection of signed malware

With the massive Sony leaks (including their private keys/certificate), i was wondering: How do major AVs deal with signed binaries? ie: Does it influence their detecting ability of the signed ...
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6answers
21k views

Will antivirus detect all keyloggers?

Our company schedules Security Training courses for our personnel. In order for us to test them, we develop code such as keyloggers which we email to our personnel to detect stupid personnel, and of ...
14
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8answers
3k views

Are antiviruses still useful? [duplicate]

Are anti-viruses useful nowadays ? Given the number of viruses that are developed and spread monthly, and given the fact anti-viruses are based on virus signatures, I wonder how much it is useful and ...
2
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2answers
7k views

Where to download thousands of virus samples for AV testing?

I'm making an antivirus test just for my own, and I need thousands of malware samples (about 10k-30k, but the more the better). Please don't even mention Eicar test file because this will be a ...
0
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1answer
265 views

Do SSL proxies such as those from antivirus vendors hijack client processes?

In an attempt to understand the topic further, the following posts were reviewed. Why is 'avast! Web/Mail Shield Root' listed as CA for google.com? Are the certificates from “skype click to call” ...
6
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4answers
13k views

Is it necessary to scan users' file uploads by antivirus?

Web application allows users to upload files. Is it necessary to scan those files by antivirus? I'd want to hear answer in two scenarios: Type of file isn't checked when uploading. They are stored ...
4
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3answers
4k views

Is there a way to use VirusTotal.com offline?

I live at a place where we don't always always have internet. I wonder if there is something like VirusTotal but that could work without internet connection and sync when I have some wifi to update ...
4
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1answer
669 views

What is quarantine?

What do antiviruses actually do when quarantining a malicious threat? Does it compress the file using some algorithm, does it just change the extension of the file, or does it just move the file to a ...
3
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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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2answers
398 views

Which MTA don't have antivirus check for outbound emails? [closed]

I need to test whether MTA has antivirus check for inbound emails. To check this I need to send email with e.g. EICAR testfile from another MTA to this one. However, Gmail, Yahoo and other well-known ...
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2answers
4k views

What is the difference between Heuristic-based and Behaviour-based virus scanning?

I'm struggling to see the difference as all papers and notes I've read seem to contradict each other. Can someone please explain to me the difference between heuristic and behaviour based virus ...
-1
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1answer
106 views

Online traffic monitoring by ISP for safety purposes [closed]

I have a question regarding approach to online security and protection against viruses, malware and phishing by one of the biggest European ISP. Below you will find my understanding of the topic. Is ...
124
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8answers
19k views

Are there technical differences which make Linux less vulnerable to virus than Windows?

What makes Linux so different than Windows in terms of anti-virus needs? My question is not if I should get an anti-virus for my Linux. I perfectly understand why an AV is important. I would like ...
102
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3answers
25k views

How are anti viruses so fast?

The common anti-virus (to my knowledge) uses a kind of brute force type method where they get the hash of the file and compare it to thousands of known virus' hash. Is it just they have servers with ...
52
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10answers
16k views

Replacing Windows 7 security updates with anti-virus?

Microsoft has announced Windows 7 will no longer be receiving updates after January 14, 2020: Here. I hate windows 10's forced updates and telemetry so I have always stuck with Windows 7, but it may ...
82
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2answers
17k views

I'm a White Hat and I develop my own viruses. Should I report it when almost all scanners say the executable is safe?

I develop my own viruses for 'scientific' purposes, namely to see if they pass the test of Virustotal.com. They all do, except for one or two scanners. Is this considered something you should report ...
33
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4answers
4k 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 ...
38
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5answers
46k views

Is HTML5 vibrate feature a security vulnerability?

While surfing a news website on my mobile, I receive a virus infection alert warning that triggers my phone to vibrate incessantly. The alert looks like the following: I didn't expect my phone to ...
23
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2answers
3k 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 ...
17
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4answers
13k views

Do Linux systems need antivirus against ransomware? [closed]

I use Linux to store private data and backups for my team because it is said that Linux is itself very secure from malware and doesn't need antivirus. But now as ransomware is spreading and has ...
20
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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 ...
39
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4answers
8k views

Avast AV could read Firefox saved passwords

My friend uses Firefox's built-in password manager feature to save passwords for sites. Later, after installing Avast Free Antivirus there was a feature called Passwords on the Avast UI. When accessed ...
16
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2answers
12k views

How to pass PCI DSS 2.0 anti-virus requirement (5.1) on Linux?

PCI DSS 2.0 Requirement 5.1 states: 5.1 Deploy anti-virus software on all systems commonly affected by malicious software (particularly personal computers and servers). This requirement (although ...
15
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6answers
12k views

How can I safely back-up files from an infected computer?

Imagine a laptop that's been infected by malware, and that the owner hasn't backed-up their files.* They have pictures, videos, and documents they'd like to preserve, so they're hesitant to ...
15
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4answers
9k views

Can I block viruses from a USB stick by scanning it before opening its folder?

I inserted my USB stick into a friend's PC which was full of viruses, malwares and adwares. Therefore I suppose they attacked my USB device as well. Now I want to use my USB device on my PC without ...
10
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6answers
7k views

Whats the probability of a personal computer being hacked?

For a normal computer user following these practices: Have an up to date anti-virus with a firewall installed (Norton). Do not install cracked software. Do not open suspicious links or download ...