371
votes
20answers
57k views
XKCD #936: Short complex password, or long dictionary passphrase?
How accurate is this XKCD comic from August 10, 2011?
XKCD 936: Password Strength
I've always been an advocate of long rather than complex passwords, but most security people (at least the ones ...
315
votes
17answers
36k views
How can I explain SQL injection without technical jargon?
I need to explain SQL injection to someone without technical training or experience. Can you suggest any approaches that have worked well?
211
votes
13answers
36k views
What technical reasons are there to have low maximum password lengths?
I have always wondered why so many websites have very firm restrictions on password length (exactly 8 characters, up to 8 characters, etc). These tend to be banks or other sites I actually care about ...
203
votes
22answers
287k views
I found that the company I work for is putting a backdoor into mobile phones
I have found out recently that the remote assistant software that we put in a smartphone we sell can be activated by us without user approval.
We are not using this option, and it is probably there ...
198
votes
16answers
19k 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 ...
196
votes
9answers
20k views
Is my developer's home-brew password security right or wrong, and why?
Our developer, let's call him 'Dave', insists on using a home-brew script for hashing passwords. See Dave's proposal below.
We have already researched and adopted an industry standard protocol using ...
172
votes
3answers
45k 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.
...
168
votes
13answers
27k views
Are passwords stored in memory safe?
I just realized that, in any language, when you save a password in a variable, it is stored as plain text in the memory.
I think the OS does its job and forbids processes from accessing each other's ...
168
votes
4answers
41k 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 ...
147
votes
3answers
32k views
CRIME - How to beat the BEAST successor?
With the advent of CRIME, BEASTs successor, what is possible protection is available for an individual and / or system owner in order to protect themselves and their users against this new attack on ...
138
votes
18answers
7k views
Passwords Being Sent in Clear Text Due to Users' Mistake in Typing it in the Username Field
Upon reviewing the Logs generated by different SIEMs (Splunk, HP Logger Trial and the AlienVault platform’s SIEM) I noticed that for some reason quite a few users tend to make the mistake of typing ...
130
votes
8answers
52k views
Why not use larger cipher keys?
RSA Security commonly uses keys of sizes 1024-bit, 2048-bit or even 3072-bit. And most Symmetric algorithms only between 112-bit and 256-bit. I do realize that the current keys are secure enough for ...
130
votes
9answers
8k 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 ...
126
votes
12answers
18k views
How is an ATM secure?
I'm curious why an ATM computer is considered secure. The general adage of "If an attacker has physical access to my machine, all bets are off," seems to not apply in this circumstance (since ...
121
votes
7answers
8k 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 ...
117
votes
7answers
6k views
How do certification authorities store their private root keys?
Knowledge of a CA private key would allow MitM attackers to transparently supplant any certificates signed by that private key. It would also allow cyber criminals to start forging their own trusted ...
114
votes
11answers
14k 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 ...
113
votes
7answers
17k views
CTRL+ALT+DEL Login - Rationale behind it?
Maybe a rather noobish question: Why is CTRL+ALT+DEL required at login on Windows systems (I have not seen it elsewhere, but contradict me if I'm wrong) before the password can be typed in? From a ...
106
votes
10answers
5k views
What alternatives are there when SSH is being actively filtered?
Unfortunately our government filters the SSH protocol so now we can't connect to our Linux server.
They do the filtering by checking the header of each packet in the network layer (and not by just ...
104
votes
18answers
7k views
What should I do when my boss asks me to fabricate audit log data?
My boss just asked me to create a fictitious log entry to say that a user's account was updated before it was, to win a dispute.
I feel this is not right because I am trying to start a career in ...
96
votes
8answers
8k views
Are “man in the middle” attacks extremely rare?
In
http://cdixon.org/2012/02/12/the-iphone-contact-list-controversy-and-app-security/
Chris Dixon makes a statement about web security
Many commentators have suggested that a primary security ...
86
votes
8answers
8k views
Is Google spying on all of us?
I am curious because, I experienced something bizarre recently. About a month ago, someone asked me to find out a price for a T-shirt printing machine, and probably for the first time, I pressed these ...
83
votes
8answers
4k views
Attacking an office printer?
I did an nmap scan on an advanced office printer that has a domain name and is accessible from outside the corporate network. Surprisingly I found many open ports like http:80, https:443, and ...
76
votes
13answers
6k views
Why do we lock our computers?
It's common knowledge that if somebody has physical access to your machine they can do whatever they want with it1.
So why do we always lock our computers? If somebody has physical access to my ...
72
votes
3answers
43k views
RSA vs. DSA for SSH authentication keys
When generating SSH authentication keys on a Unix/Linux system with ssh-keygen, you're given the choice of creating a RSA or DSA key pair (using -t type).
What is the difference between RSA and DSA ...
70
votes
7answers
4k views
How can I protect my internet-connected devices from discovery by Shodan?
There's been a lot of buzz around this recent CNN article about Shodan, a search engine that can find and allow access to unsecured internet-connected devices.
Shodan runs 24/7 and collects ...
69
votes
7answers
3k views
How do I know a piece of software only does what the author claims?
Without being a programmer or a computer expert, how can I know if a particular program or any piece of software in general doesn't have hidden unwanted functions compromising privacy and security?
69
votes
12answers
15k 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 ...
68
votes
7answers
3k views
Is social-engineering an actual threat
I've recently finished book The Art of Deception: Controlling the Human Element of Security by Kevin Mitnick
The book was released on 4th December 2002. Not talking only about techniques described ...
68
votes
13answers
6k views
What “hacking” competitions/challenges exist?
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 ...
67
votes
16answers
2k views
At what point does something count as 'security through obscurity'?
So, I keep finding the conventional wisdom that 'security through obscurity is no security at all', but I'm having the (perhaps stupid) problem of being unable to tell exactly when something is 'good ...
66
votes
16answers
15k views
Lessons learned and misconceptions regarding encryption and cryptology
Cryptology is such a broad subject that even experienced coders will almost always make mistakes the first few times around. However encryption is such an important topic, often we can't afford to ...
64
votes
8answers
4k views
How would one crack a weak but unknown encryption protocol?
I was reading this interesting question:
Is my developer's home-brew password security right or wrong, and why?
It shows a weak home-brew algorithm developed by "Dave", and the answers discuss ...
62
votes
11answers
5k views
“Username and/or Password Invalid” - Why do websites show this kind of message instead of informing the user which one was wrong?
Lets say a user is logging into a typical site, entering their username and password, and they mistype one of their inputs. I have noticed that most, if not all, sites show the same message (something ...
61
votes
11answers
8k views
Why are hash functions one way? If I know the algorithm, why can't I calculate the input from it?
Why can't a password hash be reverse engineered?
I've looked into this ages ago and have read lots on it, but I can't find the explanation of why it can't be done. An example will make it easier to ...
60
votes
13answers
5k views
VP of IT claims he unhashed 100% of all 16k employees' PWs. Is he lying to us?
I work for a company which has ~16,000 employees. Periodically, our VP of IT sends out a newsletter with "tech-tips" and misc IT stuff. The topic of this week's newsletter was "password security". ...
58
votes
9answers
8k views
What would one need to do in order to hijack a satellite?
I realise this borders on sci-fi, but there's been some interesting demonstrations regarding security of various satellites.
What would be required to hack a satellite (in general terms, any hack ...
58
votes
12answers
10k views
Apache Server Hardening
What are some best practices, recommendations, required reading for securing an Apache Server?
56
votes
15answers
3k 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 ...
53
votes
9answers
7k views
How can PayPal spoof emails so easily to say it comes from someone else?
When I receive a payment in PayPal, it sends me an email about it (pictured below). The problem is that the email is shown to be coming from the money sender's email address and not from PayPal ...
53
votes
11answers
6k views
How can I punish a hacker?
I am a small business owner. My website was recently hacked, although no damage was done; non-sensitive data was stolen and some backdoor shells were uploaded. Since then, I have deleted the shells, ...
53
votes
12answers
3k 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 ...
52
votes
10answers
3k views
Does disabling right click have any impact on security?
On a banking website I see that they have disabled right-click. Does that make the site any more secure? Is it a good general practice?
51
votes
8answers
6k views
Why would someone trust DuckDuckGo or other providers with a similar privacy policy?
DuckDuckGo is a search engine that claims it will not share your results with others. Many of my skeptical coworkers think it may be a scam.
Is there any proof that any web search engine will ...
51
votes
19answers
5k views
How can I avoid my password being harvested by key loggers from internet cafes?
During traveling, especially in poor countries, sometimes you are going to need to use the internet at an internet cafe and you really can't be sure whether anyone has installed anything to listen to ...
50
votes
13answers
7k views
Why do sites implement locking after 3 failed password attempts?
I know the reasoning behind not letting infinite password attempts -- brute force attempts is not a meatspace weakness, but a problem with computer security -- but where did they get the number 3 ...
49
votes
8answers
5k 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 ...
48
votes
10answers
4k 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 ...
48
votes
12answers
2k views
How do you log in from an unsecured computer?
Suppose that you are on a cybercafe, at a friend's home or at your work office, and you need to log in on a site, but you feel that the the computer can not be trusted (e.g. your friend isn't ...
47
votes
15answers
5k views
How is “hacking” even possible if I “defend” properly?
On a Linux-based server, I follow basic practices as below:
Make the admin account password long and complicated enough (i.e. theoretically speaking, password cannot be cracked within reasonable ...
