211
votes
12answers
33k views

How to securely hash passwords?

If I hash passwords before storing them in my database, is that sufficient to prevent them being recovered by anyone? I should point out that this relates only to retrieval directly from the ...
480
votes
23answers
88k views

XKCD #936: Short complex password, or long dictionary passphrase?

How accurate is this XKCD comic from August 10, 2011? I've always been an advocate of long rather than complex passwords, but most security people (at least the ones that I've talked to) are ...
230
votes
4answers
65k views

Do any security experts recommend bcrypt for password storage?

On the surface bcrypt, an 11 year old security algorithm designed for hashing passwords by Niels Provos and David Mazieres, which is based on the initialization function used in the NIST approved ...
321
votes
3answers
113k views

How does SSL work?

How does SSL work? I just realised we don't actually have a definitive answer here, and it's something worth covering. I'd like to see details in terms of: A high level description of the protocol. ...
158
votes
6answers
16k views

How to store salt?

Nowadays, if we expect to store user password securely, we need at least do the following thing $pwd=hash(hash($password) + salt) then store $pwd in your system instead of the real password. I have ...
53
votes
5answers
19k views

Password Hashing add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
53
votes
8answers
26k views

How secure are virtual machines really? False sense of security?

I was reading this CompTIA Security+ SYO-201 book, and the author David Prowse claims that: Whichever VM you select, the VM cannot cross the software boundaries set in place. For example, a ...
32
votes
3answers
12k views

What are the career paths in the computer security field?

What sorts of jobs are there, in which organizations, with what sorts of day-to-day responsibilities? What areas are good for folks coming out of school, vs what are good 2nd careers for experienced ...
236
votes
10answers
26k views

Is my developer's home-brew password security right or wrong, and why?

A developer, let's call him 'Dave', insists on using home-brew scripts for password security. See Dave's proposal below. His team spent months adopting an industry standard protocol using Bcrypt. ...
66
votes
15answers
6k views

Does an established ssl connection mean a line is really secure

From the view of somebody offering a webapplication. When somebody connects with SSL (https) to our service and submits the correct authentication data, is it safe to transmit all sensitive data over ...
46
votes
13answers
7k views

What are the pros and cons of site wide SSL (https)?

What are the pros and cons of encrypting all HTTP traffic for the whole site through SSL, as opposed to SSL on just the login page?
174
votes
8answers
15k views

How is it possible that people observing an HTTPS connection being established wouldn't know how to decrypt it?

I've often heard it said that if you're logging in to a website - a bank, GMail, whatever - via HTTPS, that the information you transmit is safe from snooping by 3rd parties. I've always been a little ...
41
votes
1answer
5k views

What should end-users do about Heartbleed?

What should one do about the Heartbleed OpenSSL exploit? mainly talks about what people running websites should do about Heartbleed. What should end-users of websites be doing? Do they need to ...
28
votes
8answers
6k views

How can I reliably erase all information on a hard drive?

As storage technologies change over time, using different encodings and remappings to deal with sector errors, the best way to permanently erase/wipe/shred data changes also. Methods for flash drives ...
184
votes
3answers
41k views

CRIME - How to beat the BEAST successor?

With the advent of CRIME, BEAST's successor, what possible protection is available for an individual and/or system owner in order to protect themselves and their users against this new attack on TLS?
32
votes
2answers
6k views

Amount of simple operations that is safely out of reach for all humanity?

Cryptographic primitives usually assert some security level given as number of operations to mount an attack. Hash functions, for example, give different security levels for collision attacks, ...
19
votes
2answers
991 views

How do I deal with a compromised server?

I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism: What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", ...
21
votes
10answers
3k views

Resources to learn about security

I am currently just finishing a undergrad computer science degree, but I know very little about computer security. What are some good resources (aside from this site) to learn the fundamentals of ...
56
votes
2answers
8k views

What are rainbow tables and how are they used?

Where can I find one? Is there a pot of gold at the end? How do I protect against them? From the Area51 proposal This question was IT Security Question of the Week. Read the Sep 09, 2011 blog ...
27
votes
11answers
3k views

How feasible is it for a CA to be hacked? Which default trusted root certificates should I remove?

This question has been revised & clarified significantly since the original version. If we look at each trusted certificate in my Trusted Root store, how much should I trust them? What factors ...
61
votes
9answers
9k views

Hardening Linux Server

We have already had questions on here about Hardening Apache, Hardening PHP and Securing SSH. To continue this trend I am interested in what steps people take to harden Linux servers. As in what ...
27
votes
4answers
3k views

Are there DRM techniques to effectively prevent pirating?

A question on Skeptics.SE asks whether current DRM techniques effectively prevent pirating: Is DRM effective? The question for IT Security is: Can DRM be made effective, and are there any examples? ...
60
votes
3answers
7k views

Is a rand from /dev/urandom secure for a login key?

Lets say I want to cookie for a user, would simply going to /dev/urandom, generating a 1024 bit string, checking if it already exists (and looping till I get a unique one) suffice? Or should I be ...
58
votes
6answers
6k views

Can anybody explain XSS?

I work programming Enterprise Java applications and do very little web development in 2002. I'm interested in security and like to read articles about it. However, I never fully understand how XSS ...
33
votes
4answers
4k views

Why shouldn't we roll our own?

Why shouldn't we create our own security schemes? I see a lot of questions around here about custom crypto and custom security mechanisms, especially around password hashing. With that in mind, I'm ...
243
votes
18answers
35k views

How does changing your password every 90 days increase security?

Where I work I'm forced to change my password every 90 days. This security measure has been in place in many organizations for as long as I can remember. Is there a specific security vulnerability ...
38
votes
41answers
7k views

What is your way to create good passwords that can actually be remembered?

What are the methodologies which can be used to generate "human" good quality password? They have to ensure a good strength and also easy to remember for a human being.
75
votes
14answers
14k views

Apache Server Hardening

What are some best practices, recommendations, required reading for securing an Apache Server?
59
votes
8answers
6k views

Can anyone provide references for implementing web application self password reset mechanisms properly?

We are implementing self password reset on a web application, and I know how I want to do it (email time limited password reset URL to users pre-registered email address). My problem is that I ...
82
votes
12answers
20k views

Why is it difficult to catch “Anonymous” or “Lulzsec” (groups)?

I'm not security literate, and if I was, I probably wouldn't be asking this question. As a regular tech news follower, I'm really surprised by the outrage of Anonymous (hacker group), but as a ...
23
votes
5answers
2k views

Professional certifications for IT Security

Which credentials of the sub-list of IT certifications (as per the Information Systems Security Association) would be considered MUST HAVE for a IT Security specialist. Information Security CEH ...
34
votes
3answers
9k views

Is it enough to only wipe a flash drive once?

According to the documentation for the "diskscrb" command for wiping conventional hard drives: http://www.forensics-intl.com/diskscrb.html "Conforms to and exceeds the Government Standard set ...
20
votes
6answers
4k views

How to be completely anonymous online?

I recently saw this post on reddit: http://www.slashgeek.net/2012/06/15/how-to-be-completely-anonymous-online/ But the majority argument, both on reddit and on comments on that post seems to be that ...
171
votes
1answer
41k views

How exactly does the OpenSSL TLS heartbeat (Heartbleed) exploit work?

I've been hearing more about the OpenSSL Heartbleed attack, which exploits some flaw in the heartbeat step of TLS. If you haven't heard of it, it allows people to: Steal OpenSSL private keys Steal ...
52
votes
11answers
8k views

How reliable is a password strength checker?

I've tested the tool from Microsoft available here which tests password strength and rates them. For a password such as "i am going to have lunch tonight", the tool rates it's strength as "BEST" and ...
28
votes
4answers
10k views

Why is writing zeros (or random data) over a hard drive multiple times better than just doing it once?

Lots of different programs, such as Darik's Boot and Nuke, let you write over a hard drive multiple times under the guise of it being more secure than just doing it once. Why?
64
votes
10answers
5k 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 ...
27
votes
1answer
3k views

Are there more modern password hashing methods than bcrypt and scrypt?

This question made me start thinking about password hashing again. I currently use bcrypt (specifically py-bcrypt). I've heard a lot about PBKDF2, and scrypt. What I'm wondering is if there are any ...
39
votes
6answers
10k views

What techniques do advanced firewalls use to protect againt DoS/DDoS?

It is hard to protect a server against Denial of Service attacks, DoS/DDoS. The two simple ways I can think of is to use a server with much resources (e.g. CPU and memory), and to build the server ...
20
votes
1answer
2k views

What cookie attacks are possible between computers in related DNS domains (*.example.com)?

Here, several servers in the same DNS domain emit cookies under a variety of settings (scope, HTTPS, Secure) and another host emits a cookie with the same value. Example Suppose a user has the ...
25
votes
5answers
2k views

Open Source vs Closed Source Systems

My understanding is that open source systems are commonly believed to be more secure than closed source systems. Reasons for taking either approach, or combination of them, include: cultural norms, ...
24
votes
4answers
1k views

How is “something you have” typically defined for “two-factor” authentication?

A wide range of products claim to offer "two-factor authentication" (c.v. Two-factor authentication - Wikipedia). Most are deployed as "something you have" to be used in addition to a normal password ...
24
votes
10answers
821 views

Does hashing a file from an unsigned website give a false sense of security?

Consider this. Many websites with software downloads also make available MD5 or SHA1 hashes, for users to verify the integrity of the downloaded files. However, few of these sites actually use HTTPS ...
38
votes
3answers
9k views

Are all SSL Certificates equal?

After running a few tests from Qualsys' SSL Labs tool, I saw that there were quite significant rating differences between a GoDaddy and VeriSign certificate that I have tested against. Are all SSL ...
15
votes
6answers
2k views

Anonymous web browser. Is it real?

Do anonymous browsers work? What principles do they use? Can I use them to test access to my web site? Can I detect if a visitor is using one? What is the different between traditional and anonymous ...
14
votes
5answers
1k views

Different strategies for online anonymity and their +/-s?

I saw this question about anonymous web browser, but I wanted to go a little bit more in depth. I prefer answers that take into account how a connection would be traced back, time it would take to ...
19
votes
4answers
2k views

Why is using salt more secure?

Storing the hash of users' passwords, e.g. in a database, is insecure since human passwords are vulnerable to dictionary attacks. Everyone suggests that this is mitigated via the use of salts, but the ...
12
votes
2answers
856 views

Protecting cellphones from USB attacks (a.k.a. Juice Jacking)

We have several smartphone with encrypted data on them (BES, iPhone, Android) and want to prevent an unauthorized person from downloading information from the device via USB. The visual assumption ...
82
votes
15answers
13k views

What “hacking” competitions/challenges exist? [closed]

I have always enjoyed trying to gain access to things I'm not really supposed to play around with. I found Hack This Site a long time ago and I learned a lot from it. The issue I have with HTS is that ...
60
votes
6answers
9k views

How much can I trust Tor?

How much can I depend on Tor for anonymity? Is it completely secure? My usage is limited to accessing Twitter and Wordpress. I am a political activist from India and I do not enjoy the freedom of ...

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