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270 votes
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Search for military installed backdoors on laptop

If the device left your sight for any amount of time, replace it. It can no longer be trusted. The cost to assure it can still be trusted significantly exceeds the cost of getting a new one There is ...
forest's user avatar
  • 66.6k
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
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
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188 votes
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What should you do if you catch encryption ransomware mid-operation?

Hibernate the computer If the ransomware is encrypting the files, the key it is using for encryption is somewhere in memory. It would be preferable to get a memory dump, but you are unlikely to have ...
Ángel's user avatar
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177 votes
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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
163 votes
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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 ...
143 votes
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Can Beehive detect a Snowden-like actor?

A backup operator will have the permission and behavioral markers of someone that moves lots of data around. Like any sysadmin where there's no dedicated backup operator in place. Snowden was a ...
ThoriumBR's user avatar
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141 votes
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How to investigate an unknown 1.5GB file named "sudo" in my Linux home directory?

You probably made it by accident with a botched shell command. I've done stuff like that myself. As a result it is probably filled with innocuous data. Here are a few reasons why I would guess it is ...
Conor Mancone's user avatar
136 votes
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How is the "WannaCry" Malware spreading and how should users defend themselves from it?

WannaCry attacks are initiated using an SMBv1 remote code execution vulnerability in Microsoft Windows OS. The EternalBlue exploit has been patched by Microsoft on March 14 and made publicly available ...
Nik Nik's user avatar
  • 1,292
134 votes
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If malware does not run in a VM why not make everything a VM?

One has to take into account why the malware is doing this distinction in the first place. Some malware does not run in the VM because the chance is high that this VM is used for inspecting the ...
Steffen Ullrich's user avatar
132 votes
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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
  • 66.6k
129 votes
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Can a malware power on a computer?

TL;DR Yes, but it's unlikely. Just to be sure, either unplug the PC or ensure it can't connect to anything. Several operating systems - notably Windows 10 - have the possibility of setting "...
LSerni's user avatar
  • 22.8k
123 votes
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Can a virus destroy the BIOS of a modern computer?

Modern computers don't have a BIOS, they have a UEFI. Updating the UEFI firmware from the running operating system is a standard procedure, so any malware which manages to get executed on the ...
Philipp's user avatar
  • 49.4k
100 votes

My email address is being used to enroll for online services. Should I be concerned?

Should I be concerned about this? Yes. This should be of concern to you because an attacker was able to obtain the valid password for your Gmail account. From the details of warning you have ...
hax's user avatar
  • 3,951
100 votes
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Can malicious code fit in 14 bytes?

Yes, it can. It could be just the trigger vulnerability which would load data on specific areas of the movie in memory and execute. The malicious part can be pretty small, and the payload could be ...
ThoriumBR's user avatar
  • 53.9k
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
93 votes
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Can cookies carry viruses?

You can put any text strings into a cookie, so in theory you could put some kind of code there. But for code to do any harm something needs to run it. The web browser does not interpret the content of ...
Anders's user avatar
  • 65.5k
93 votes

What happens if you run WannaCry after installing the necessary patches?

If you download and execute WannaCry, it will still lock your files and attempt to infect other unpatched computers in the network. WannaCry only needs the SMB exploit to get into a system, not to ...
knbk's user avatar
  • 751
86 votes
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Does open source "protestware" represent a security risk?

Political statements in software can be a concern for a few reasons: The may result in the software being banned in your country, so you should plan for that eventuality. They may result in the ...
Gh0stFish's user avatar
  • 10.1k
85 votes
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Can headphones transmit malware?

I doubt there is a way to store any information (thus transfer information) on regular headphones. Some more advanced models (such as noise canceling) have some processing ability and firmware, but I ...
Stephen Spencer's user avatar
85 votes
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Would a CD drive on a driverless car pose a security risk?

Not on a well-designed car The CD player is part of the media system. It's likely that the media system has a number of security vulnerabilities, and a malicious CD can probably take control of the ...
paj28's user avatar
  • 33.4k
82 votes
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What is the risk of copy and pasting Linux commands from a website? How can some commands be invisible?

Websites can append to your clipboard The risk is exactly what you said it was. It's definitely possible to append malicious commands to the clipboard. You could even append && rm -rf /* (...
Mark Buffalo's user avatar
  • 22.6k
78 votes

What should you do if you catch encryption ransomware mid-operation?

What I would do: Suspend the process. Don't kill it, just pause it. Look in the process tree if there are any parents that might need suspending as well. Pull the network cable and/or turn off WiFi (...
Luc's user avatar
  • 32.9k
75 votes
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Was Goggle.com actually crazy malware in 2006?

Let me summarise what you are seeing: someone navigates to a typo-squat site (goggle.com) the browser is then flooded with numerous pop-ups, warning windows, etc. eventually, the anti-virus starts to ...
schroeder's user avatar
  • 129k
73 votes
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Can the previewable option in file managers execute malware?

Yes, it is possible for previews to execute malicious code. Previews are created by checking the file type, and generating a thumbnail. For images, it resizes them. For videos, it decodes them, seeks ...
forest's user avatar
  • 66.6k
73 votes

Search for military installed backdoors on laptop

The main information we are lacking is your threat model. Is it likely that the military targets you specifically, and would be willing to expend some resources on you? We don't need to know the ...
Tom's user avatar
  • 10.3k
69 votes

How can empty USB sticks contain malware?

I'm afraid this stems from a misunderstanding from the reporter: ... said a device that appeared to be empty could still contain a virus. In the video the reporter's referring to it is clear, in ...
autistic's user avatar
  • 759
67 votes
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Is it dangerous to call spam phone numbers, even if you know they're spammers?

Can you get "hacked" by calling a number? I am curious if calling the number would do something to my phone. How could a hacker possibly access sensitive information just by tricking someone into ...
Mark Buffalo's user avatar
  • 22.6k
66 votes

Can a malware power on a computer?

As others have mentioned, it is quite possible on most PC hardware, although currently not very likely (as vast majority of malware does not bother). What others have said is not possible is however ...
Matija Nalis's user avatar
  • 2,285

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