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211 votes
Accepted

Is momentary physical access dangerous?

That all depends on the system, the attacker, and the level of preparation they had. If they have unlimited preparation, they could do effectively anything that they could do with an unlimited access ...
forest's user avatar
  • 66.9k
192 votes

4-dial combination padlock: Is it more secure to zero it out or to blindly spin the dials after locking?

I would recommend setting it to 0000 or some other specified combination (doesn't really matter what). "Mashing around the dials" is a little vague, but I would guess based on my own behavior that ...
AndrolGenhald's user avatar
137 votes
Accepted

Defence methods against tailgating

This is not a problem that has a social solution. No amount of corporate policy will save you. Humans are social animals. In the end, if people can let other people in, they will. Even if you may be ...
Anders's user avatar
  • 65.6k
129 votes
Accepted

Why are my plastic credit card and activation code sent separately?

Many low level crimes are ones of opportunity, not planned out attacks. By separating the two needed pieces of mail in time, it forces the attacker to intercept the same person's mail more than once. ...
Steve Sether's user avatar
  • 21.6k
119 votes
Accepted

4-dial combination padlock: Is it more secure to zero it out or to blindly spin the dials after locking?

In theory zeroing or any predetermined sequence is more secure as you could, in theory make a guess at how far someone might move the dials. It is also conceivable that if you were able to check the ...
Chris Johns's user avatar
  • 1,226
117 votes

How is 'Removing RAM' a security risk?

RAM is used to store sensitive non-persistent information in a lot of cases. Encryption keys would be a common example. Sometimes it is possible to remove RAM and place it into another device to ...
Peleus's user avatar
  • 3,907
113 votes
Accepted

How resistant are barcodes and QR-codes against attempts to change stored data?

... how secure is a QR-code? Data in a QR code are kind of protected against accidental damage by having some error correction but they are not protected against deliberate manipulation. Also, an ...
Steffen Ullrich's user avatar
113 votes
Accepted

What is the purpose of the rotating plate in front of the lock?

It's called anti-drill plate. With the anti-drill rotating plate, the drill bit won't be able to go through the cylinder. It's supposed to be in hardened steel and act as an other layer of security. ...
Deunis's user avatar
  • 759
81 votes
Accepted

Why is iPhone's internal storage so hard to crack/decrypt?

I don't think that you interpret the rule you've heard in the right way. If an attacker has physical access to an encrypted but switched off device he cannot simply break the encryption provided that ...
Steffen Ullrich's user avatar
75 votes
Accepted

Secure USB cable for charging in untrusted environments

Could I mitigate that risk by taking a regular usb cable and cutting the data (but not the power) cables? Or does the usb protocol needs a data handshake to begin charging? Such a cable does exist, ...
Alexander O'Mara's user avatar
63 votes

Why does one need a strong password on Unix?

You seem to have a pretty clear understanding of the risks. As others have stated it highly encouraged to use a strong password, so if you are running a sensitive service, then by all means, please ...
700 Software's user avatar
63 votes

How resistant are barcodes and QR-codes against attempts to change stored data?

QR codes are normally not protected against manipulation. But: You could include a digital signature in the data so anyone can check if the QR code is made by you and has not been modified. Then the ...
Paul's user avatar
  • 680
63 votes

Defence methods against tailgating

You protect yourself by politely challenging people who are trying to get in without using the controls. You simply ask to see their pass or offer to escort them to reception/security. I use the ...
schroeder's user avatar
  • 131k
62 votes

Emergency method to erase all data off a machine within seconds

Thermite. Thermite burns at a temperature of thousands of degrees centigrade, which would be more than sufficient to destroy all the data stored in any modern data storage medium. It is also already ...
nick012000's user avatar
59 votes

How "scrambled" is the data on a RAID5 disk?

Raid 5 stripes the data across the disks but the blocks used for striping are typically pretty big. At the very least they will bewhole sectors but normally they will much larger than that. For ...
Peter Green's user avatar
  • 5,300
54 votes
Accepted

Emergency method to erase all data off a machine within seconds

There are two DEFCON videos from 2012 and 2015 exploring this exact issue: DEFCON 19: And That's How I Lost My Eye: Exploring Emergency Data Destruction DEFCON 23: And That's How I Lost My Other Eye.....
Slava Knyazev's user avatar
52 votes

What to do if caught in a physical pentest?

There's a flip side: what to do if you discover a physical pentester. When I was working at a bank, I happened to notice the iconic metasploit cli welcome banner flash up for a second on a desktop in ...
schroeder's user avatar
  • 131k
51 votes

Secure USB cable for charging in untrusted environments

USB devices can negotiate the provided current from the host device. If power negotiation is not possible (because you cut the data wires), a maximum of 100 mA is supplied. This means you can charge ...
Sjoerd's user avatar
  • 31.3k
50 votes
Accepted

Is it possible to improve brute-force guessing of a password with a picture of the keyboard used to enter it?

In some cases yes, you can guess the most frequently used keys by the wear marks. That's how I know that apparently I use the L, M, N, A and E keys a lot - the keys are now just black, the letter is ...
LSerni's user avatar
  • 22.9k
48 votes

How resistant are barcodes and QR-codes against attempts to change stored data?

A QR code or barcode is just data written in a non-alphabetic format. It offers no more security than you'd get from writing the same data in ordinary text.
David Richerby's user avatar
48 votes

Why did they stop adding physical "write protect" mechanism?

Floppy disks used to have a physical means of preventing writing to them. No software could bypass that, no matter what. It had to be flicked physically and manually by a human being. They didn't. It ...
vidarlo's user avatar
  • 16.6k
44 votes

Emergency method to erase all data off a machine within seconds

If you trust encryption then you could encrypt your entire drive using Linux: LUKS (supported by all major distributions) Windows: BitLocker As soon as you physically switch off the device, all the ...
Artem S. Tashkinov's user avatar
41 votes

Secure USB cable for charging in untrusted environments

Although not entirely in line with the OP's question, I wanted to share a different solution. You could take a powerbank with you. Small powerbanks capable of charging your phone at least 1 time don'...
BlueCacti's user avatar
  • 950
39 votes

Defence methods against tailgating

The cheap solution is to put up scary “no tailgating - everyone must badge in at this door - no exceptions - don’t risk your job - report all tailgate requests to Joe at 123-456-7890” signs at each ...
John Deters's user avatar
  • 34.3k
39 votes

What is the purpose of the rotating plate in front of the lock?

What Deunis said, except it is not only an anti-drill plate. The fact that it rotates freely makes it anti-drill on top. Originally, these were an upgrade for existing lock cylinders which didn't ...
Damon's user avatar
  • 5,221
36 votes
Accepted

How "scrambled" is the data on a RAID5 disk?

In the interests of actually testing this, I pointed a copy of Foremost at a slightly-damaged disk that was formerly part of a RAID-6 array. The array had a chunk size of 512KB, so any file of 512KB ...
Mark's user avatar
  • 34.7k
35 votes
Accepted

Can fingerprint readers be trusted?

It's certainly possible that the fingerprint reader contains some kind of backdoor or malicious code. But that's also true of the motherboard, the network card(s), the camera and microphone, the CPU, ...
Gh0stFish's user avatar
  • 12.9k
34 votes

4-dial combination padlock: Is it more secure to zero it out or to blindly spin the dials after locking?

It does not matter. A lock can provide three forms of protection: Delay an attacker from accessing a resource so that they can be interrupted and stopped Provide evidence of tampering Dissuade a ...
jpmc26's user avatar
  • 843

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