Tag Info

New answers tagged

5

The iso 27001 is* about documenting what you do, how you do it and what controls you have in place to audit that things are the way they are supposed to be. That means that the typical laptop installs is very very standardized with 2 maybe 3 sort of templates (how you do it). The pc are likely to be installed in an active directory with gpo enforced and ...


10

One of ISO 27001 requirements is management of access control to company's IT resources. If you just install Ubuntu on your laptop, all the access control will be managed by you directly, instead of your company. So when, for example, your manager will want to fire you, then your IT department won't be able to block your local laptop account in a convenient ...


2

Writing to /dev/null is as safe as the OS allows. You're using it for the exact purpose it was built for, redirecting output to nowhere. /dev/null is part of the UNIX philosophy where everything is a file, including devices. It's a special file recognized by the kernel, and the output is never written anywhere. Anyone with root level access could still ...


4

Is it possible to replace /dev/null with something else. Try it (as root): mv /dev/null /dev/null-real mkfifo /dev/null # Create a FIFO pipe to read/write data while read line; do echo "Incoming: $line"; done < /dev/null & echo secretdata > /dev/null You will see a message saying Incoming: secretdata in your terminal. This is because the "while ...


1

The reason people are concerned about the RDRAND instruction is that it is a proprietary hardware random generator and has never been formally analyzed. Without that analysis, there's no way to tell if it's a genuine hardware random number generator or, for example, a simple counter being passed through a cryptographic hash. In the latter case, the output ...


4

Yes, it's possible. The WCE product you reference works by scraping passwords directly out of memory. That method also works in Linux; a rootkit which has unfettered access to memory and can hook system calls can extract passwords from there - consider this example, which can steal username and password pairs Both solutions are limited in that they can ...


1

I wrote that exact code into an overflow.c file, and got the following main(). I disassembled with objdump --disassemble overflow 0804846d <main>: 804846d: 55 push %ebp 804846e: 89 e5 mov %esp,%ebp 8048470: 83 e4 f0 and $0xfffffff0,%esp 8048473: 81 ec a0 00 00 ...


0

I don't know if I understand well, what you want. Let me know if I understand it bad. I will assume, you want to overwrite EBP with some your value. One of the way, how to do it, is find, where begin buffer and get its address. So in debugger fill buffer with some payload of 'A' like - run AAAAAAAA Set breakpoint after calling strcpy() function. I set ...


1

Seeing some answer in another site thinks not using the root account increases security, I'm posting this. With the default timeout settings, there is an easy way to gain root privileges by adding this line in .bashrc: trap 'sudo -S touch /hacked </dev/null 2>/dev/null' debug It will create a file hacked in the root directory once the user has used ...


3

I would suggest that you try to reproduce this. Most likely, you already had an authenticated session and your system remembered it due to the keyring. A great way to test would be immediately after a reboot. aditya@20:54:20:~$ nano bash: nano: command not found... Install package 'nano' to provide command 'nano'? [N/y] y * Waiting in queue... * ...


5

It's not a "security flaw" in the sense that something is broken or that the flickers indicate a bug or an attack. Rather, it's an issue with the underlying graphic stack of Linux and the lack of semantics for privileged desktop clients. Just to get this out of the way, the flicker is most likely caused by a poor interaction between your GPU drivers and ...


2

There are at least 3 dangers: Sharing your public IP addresses - it will surely result in several kinds of unauthorized security scanning (this applies, if your servers have public IP addresses). Sharing your public IP addresses combined with possible OS version (ifconfig results on different OS-es look differently, you can compare ifconfig from modern ...


0

It depends on the type of IP information you are sharing. If you are sharing this information for a NATed network, such as a 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0.16 you should be fine as long as you are not sharing other information such as the company name, hostname, etc. IF YOU ARE DOING THIS FOR A MACHINE THAT HAS A PUBLIC IP ADDRESS, DO NOT SHARE ...


1

Using a wordlist against a web application differs from what is called "offline cracking". There are several disadvantages to this type of attack. What are wordlists used for? Wordlists can be used for two types of attacks. Offline attacks means guessing the plaintext that was used as input for a hash. An online attack is an attack where you are attempting ...


6

A salt does not make brute-forcing a single password any harder, as you correctly pointed out. Without a salt, an attacker could build one single rainbow-table, and (s)he would get all passwords at once. With a salt, the attacker has to build a rainbow-table for exactly this salt, so he cannot reuse already existing rainbow-tables. When you use a different ...


9

Salt doesn't have to be secret. However, it MUST be unique for each password. Consider this : if all your passwords are hashed with the same salt, then an attacker who gets access to your database "only" has to compute H(pwd+salt) for each possible pwd value and he gets all your passwords. If the salt is unique however, the same operation will only get him ...


2

You're right. Salting really makes password hacking more difficult for non-trivial passwords, but if some users use common passwords, can still hack the password by brute force a few thousands times. If the salt is public/stored together, like your case, it is just used to prevent pre-computed password hashes lookup, i.e. rainbow table. Thus, if for ...


0

It makes a dictionary attack a lot more difficult, if the salt is created in a smart way. For example, bcrypt uses a 128 bit salt. A salt is usually generated randomly. If it was derived only from the password or the password hash, it would indeed not add much security. If it is generated in a way that cannot be predicted by the attacker, it significantly ...


4

Hashing the password with a salt makes it much harder for an attacker to use a precomputed list of hashes (aka rainbow tables) to run the discovered hash against. It will force him to compute the hashes again for any salted password hash he wants to crack.


0

I got the same case, to check is your server are vulnerable to ShellShock: #!/bin/bash EXITCODE=0 # CVE-2014-6271 CVE20146271=$(env 'x=() { :;}; echo vulnerable' 'BASH_FUNC_x()=() { :;}; echo vulnerable' bash -c "echo test" 2>&1 | grep 'vulnerable' | wc -l) echo -n "CVE-2014-6271 (original shellshock): " if [ $CVE20146271 -gt 0 ]; then echo -e ...


0

Implementing application level encryption on Linux servers is a bit tricky as the application needs to be able to get the encryption key from somewhere and you don't want this to be in clear text anywhere. From a regulatory perspective, you'll likely want there to be dual control and split knowledge for encryption keys. You could have some level of logical ...


3

What you describe is a wrong, spam practice but it does not cause other inconvenience over the spam aspect. Browsers allow JavaScript code initiated by a user click to add bookmarks in order to allow websites to propose friendly "Bookmark this site" buttons. However such functionality can be exploited in order to store unwanted bookmarks in visitors browser ...


4

Be careful with the word "unrecoverable". It depends what level of "unrecoverable" you are going for. If you want to stop a casual computer user from reading your data from a live-boot OS, then things like shred, dd, dban will do the trick. If, however, you are worried about someone flashing the firmware of your drive, or removing the platters and putting ...


1

Use dban if you are using a regular harddisk (e.g. non SSD), it can be found at http://www.dban.org/ and should make it unrecoverable. DBAN is free erasure software designed for the home user. It automatically deletes the contents of any hard disk that it can detect. This method can help prevent identity theft before recycling a computer.



Top 50 recent answers are included