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Share Your Experience: Take the 2024 Developer Survey
235 votes
Accepted

How are anti viruses so fast?

Disclosure: I work for an anti-virus vendor. Because most anti-virus engines were born as protecting endpoints, and even now for many of them endpoint protection is major part of business, the modern ...
George Y.'s user avatar
  • 3,534
213 votes

Has it been mathematically proven that antivirus can't detect all viruses?

Under one possible interpretation of that, it's a result of Rice's theorem. A program is malicious if it performs some malicious action, which makes it a semantic property. Some programs are malicious ...
Joseph Sible-Reinstate Monica's user avatar
200 votes
Accepted

Company claims hardwire connections are a security issue

Warning: Conjecture, because none of us know their actual setup. It is very likely that the organization has their own network, which is hard-wired, as well as a guest network, which is wireless-only....
gowenfawr's user avatar
  • 72.9k
194 votes

Has it been mathematically proven that antivirus can't detect all viruses?

Actually, the opposite can be easily proved: since all computer viruses are executable code in one way or another, all you have to do is write an antivirus program that will report ANY executable code ...
walen's user avatar
  • 1,777
177 votes
Accepted

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

What do I do now? How do I get rid of the virus? The best option is what is referred to as "nuke it from orbit." The reference is from Aliens: The idea behind this is that you wipe your ...
CaffeineAddiction's user avatar
162 votes
Accepted

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

I think the safest option for you would be to use Qubes OS with its built in DisposableVMs functionality, and its “Convert to Trusted PDF” tool. What is Qubes OS? Qubes is an operating system where ...
135 votes

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

That's a pointless exercise. Most malware scanners match on fragments of binary code (aka virus signatures), and they check MD5 hashes of known infected code against their blacklists. Unless the ...
John Deters's user avatar
  • 34.2k
131 votes
Accepted

Alternatives to anti-virus for keeping oneself safe

Antivirus is more dangerous in that it parses complex attacker-controlled data in a highly privileged context. This is a recipe for privilege escalation exploits. As a result, sophisticated attackers ...
forest's user avatar
  • 66.8k
100 votes
Accepted

Replacing Windows 7 security updates with anti-virus?

Nope. After Microsoft discontinue security updates for a version of Windows there is not a safe way to run that version of Windows. Some people will promote Virtual Patching where you have a ...
David Waters's user avatar
  • 2,801
95 votes

Has it been mathematically proven that antivirus can't detect all viruses?

According to Wikipedia: In 1987, Fred Cohen published a demonstration that there is no algorithm that can perfectly detect all possible viruses. It also references this paper. That might be the ...
Harry Johnston's user avatar
66 votes

Can anti-virus/virus protection be used to spy on you?

Any software you install on your system can compromise the system and thus affect security and privacy. This can be done either willingly or because of bugs in the software. And this is doubly true ...
Steffen Ullrich's user avatar
53 votes

Avast AV could read Firefox saved passwords

Passwords saved by Firefox are not encrypted (they are encrypted but the key can be read out) until you set a master password. I don't think that this is a bug, but every virus could read those ...
RoiEX's user avatar
  • 561
52 votes

How are anti viruses so fast?

The common anti-virus (to my knowledge) use a kinda 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 ...
LSerni's user avatar
  • 22.8k
45 votes

Are there any known cases of antivirus software intentionally sending false alarms?

I have not seen false alarms, but I have seen an excessive amount of warnings/notifications, with Avast, for example. You could receive warnings about how vulnerable you 'might' be, and how you could ...
PositriesElectron's user avatar
38 votes

Replacing Windows 7 security updates with anti-virus?

No, anti-malware is not a replacement for security updates. Neil Matz summarized the Fortinet's Q2 Global Threat Landscape report for 2017, noticing: WannaCry and NotPetya targeted a vulnerability ...
Esa Jokinen's user avatar
37 votes
Accepted

Norton detects intrusion attempt from virtual machine - how is this possible?

You are assuming that the intrusion is coming from the VM to the hypervisor. A VM "breakout" is when the VM accesses the host directly. An infected VM that has access to the network can ...
schroeder's user avatar
  • 131k
35 votes
Accepted

Are there any known cases of antivirus software intentionally sending false alarms?

The problem with deliberately triggering false alarms is that users will at some point lose trust in the AV software. The rates of false positives are also an important factor in AV rankings - and ...
Arminius's user avatar
  • 44.8k
32 votes

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

I'm sorry to hear you've got a computer virus. Fortunately, thousands of people deal with virus infections daily, and in most cases, the computer and all data can be restored. By following good online ...
paj28's user avatar
  • 33.4k
30 votes

Can a virus infection spread from a PC to a PCB and back to a PC?

It's impractical for a PCB to be a vector for malware storage or attacks, but that's because PCBs don't do anything except route electrical signals between components. The components themselves... ...
CBHacking's user avatar
  • 49k
29 votes
Accepted

Do Linux systems need antivirus against ransomware?

There are actually multiple parts of the question: Is Linux affected by malware and especially ransomware? Do antivirus products exist for Linux? Do these products help against this threat? To ...
Steffen Ullrich's user avatar
29 votes
Accepted

Is it acceptable to exclude folders in antivirus?

Ah yes, ye olde problem of security tools making a system unusable. My arch nemesis. when is it acceptable to exclude folders in antivirus, and why? Short answer: There's an old adage on this site ...
Mike Ounsworth's user avatar
29 votes

Zero-day prevention. Is there a Windows program that encrypts files on-the-fly, keeping only the currently open file decrypted?

First things first: Asking for software recommendations is off topic for this site and you should instead use the Software Recommendations site. I'm going to mostly talk about why what you're asking ...
CBHacking's user avatar
  • 49k
28 votes
Accepted

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

Referring to my answer to this question (before it was migrated): No, scanning the drive without "opening the folder" isn't a secure way to protect against viruses on the drive. It's very ...
WorseDoughnut's user avatar
28 votes

Company claims hardwire connections are a security issue

It really depends on how they have set up their network, so we can only speculate. But I can provide a similar anecdote. My local library has a wifi that you can log into using your library card. ...
Mike Ounsworth's user avatar
26 votes

Has it been mathematically proven that antivirus can't detect all viruses?

The statement can't be mathematically proved unless it is reformulated as a mathematical proposition. At the very least, that requires a mathematically sound definition of what a "virus" is: which is ...
Michael Kay's user avatar
25 votes

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

Honestly, "non-technical users" are typically unaware of the basic conceptual difference between a data "file" and an "application", nevermind the minefield of subtleties in the advanced war game ...
John McNamara's user avatar
24 votes

Can a virus infection spread from a PC to a PCB and back to a PC?

That depends on the specifics of your PCBs, but in the absence of more information, I would follow your IT security team: they know more about them than us on this Q&A website. It is in theory ...
A. Hersean's user avatar
  • 10.5k
21 votes

Avast AV could read Firefox saved passwords

Firefox can decrypt the passwords without you entering a password. That means it must have the decryption key--which means any program that knows how Firefox stores things can find them. This ...
Loren Pechtel's user avatar
19 votes

Alternatives to anti-virus for keeping oneself safe

This is more opinion than fact, but the answer is a definite "Maybe!" Let's narrow our scope to Windows for a moment, since it's the biggest Anti-Virus market around. Windows Defender (the default ...
keithRozario's user avatar
  • 3,711
19 votes

Has it been mathematically proven that antivirus can't detect all viruses?

tl;dr- The answer depends on exactly what requirements you impose on the question. If you merely want to detect all viruses without further constraint, then simply flag anything and everything as a ...
Nat's user avatar
  • 1,441

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