Unix is a family of multiuser, multitasking operating system that is widely used in workstations, servers and embedded devices. The best-known Unix variant is Linux.

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unix: files have been missing and want to know what happen to files [closed]

Some how files are missing in a directory and I would like to know what happen to those files. Who has moved/deleted them? How to investigate? Can we get a history on directory?
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1answer
70 views

Implications of Bash history [closed]

I am using Salt Cloud to script my deployments of a small collection of commercial servers. Since it is cheap to get things right the first time, I'd like to avoid obvious mistakes. If I leave my ...
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2answers
279 views

Given an IP address can you ssh into /tmp without password?

I'm a Software Engineer, but I have no experience in security, so i'm trying to learn by doing (woot Experiential learning!). I know that the permission settings on the tmp folder are very relaxed. ...
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2answers
59 views

What's there to harden for a home Unix-box behind Comcast cable modem?

I'm learning that much of the security advice I come across under the "hardening" heading simply does not apply to a single-user home desktop box sitting in a private wireless IPv4 LAN behind a ...
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2answers
66 views

Creative vulnerabilities in unix eval command [closed]

I'm reading through past exams for an information security subject and I came across this. #!/bin/sh #applications launcher X=$1 eval "$X" "Do you think the program is vulnerable to attacks? ...
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1answer
38 views

Identity theft from ubuntu machine? [closed]

Recently my debit card information went to another hand, and he/she started to using it until my bank reports that there is an overdraft. I use Ubuntu 14.04 machine. I am sure I am not a victim of ...
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1answer
95 views

What RHSA, RHEA and RHBA stands for in the RedHat Erratas?

Do you know what does RHSA, RHEA and RHBA stands for in RedHat Errata ?
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1answer
302 views

Is mosh now recommended by the security experts? (2014)

Mosh has been around for a while now. Although it's claimed to be "a replacement for SSH" by its authors, mosh does actually depend on ssh to do the initial authentication, after which an instance of ...
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4answers
105 views

Why can't just any program use his own file-system-access-system?

This may sound stupid for everyone who knows more than me about the UNIX-System and security in software: Imagine you have a program trying to cause harm by deleting files. You just do something like ...
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1answer
77 views

Dangerous to open a unix socket within www root?

My web server is chrooted into /var/www, and its contents are available over the network. One of my web applications needs access to a unix socket, and so that socket needs to be somewhere in ...
3
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2answers
64 views

What are the benefits of having multiple overwriting patterns for secure deletion? [duplicate]

When installing a new AIX server, there is a possibility to use several patterns for secure deletion. My question: Is it necessary to use several patterns? What is the benefit from having several ...
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0answers
108 views

BSD encryption advantages [closed]

If someone who knows about the BSD project has a moment to answer this, I'm wondering a few things about the encryption used. It's more than what I'm finding in the docs and on Wiki/Google (even the ...
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2answers
185 views

What output can a program, when executed from a command line, output to generate behavior that is a vulnerability on the terminal emulator?

Reading this post, titled "Fixing Unix/Linux/POSIX filenames", I came across a VERY interesting phrase by the author, which says: Oh, and don’t display filenames. Filenames could contain control ...
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1answer
144 views

S/Key as an alternative to UNIX passwords

There is this password system called S/Key I saw on the Internet. Can someone give me a brief description about S/Key and how it works? Can S/Key be an alternative solution to the UNIX password ...
2
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1answer
2k views

Create netcat listener and execute reverse shell in the same script

I'm coding an exploit in python that exploits a command injection vulnerability for a CTF and I'm wondering how could I start a netcat listener and then send the payload to the remote host and once ...
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1answer
243 views

Would adding root to a group open a security hole?

I have a server for which I have created a cron job "sendalerts" to users. Mind you this "sendalerts.php" should be runnable from two methods (via browser and also via a cron job) So cron's job is to ...
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1answer
107 views

Notification or report for security problem of unix systems? [duplicate]

I have unix systems(Solaris,Oracle,Redhat vs).I have to control all system for security problem,bugs,patch,vulnerabilities I'm looking for securty information for all security issue After that I'll ...
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4answers
2k views

SHA-512 unix passwords. How secure are those hashes, really?

I came across this very alarming sounding thread which indicates a GPU with about half the compute capacity of the GPU currently powering the monitor I type this on is capable of 11.5k c/s. I'm not ...
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2answers
138 views

What is the meaning of the term “simple string” for the SALT string in Unix crypt using SHA-256 and SHA-512?

In Unix crypt using SHA-256 and SHA-512 the author, Ulrich Drepper, introduces the SALT string as the following (highlight by me): For the SHA-based methods the SALT string can be a simple string ...
70
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5answers
2k views

How can I protect myself from this kind of clipboard abuse?

Clipboard abuse from websites Many websites use JavaScript or CSS to stealthily insert or replace text in the user's clipboard whenever they copy information from the page. As far as I know this is ...
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2answers
4k views

Where is my password stored on Linux? [duplicate]

Is there a specific location where the passwords are stored ? Is it depending on which version is used ? Are they salted ?
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1answer
141 views

Do I need logging enabled in my rules in IPFW for sshguard-ipfw to work/blacklist ip's?

From the FreeBSD handbook: Even with the logging facility enabled, IPFW will not generate any rule logging on its own. The firewall administrator decides which rules in the ruleset will be ...
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2answers
178 views

Does glibc2 version of the crypt function still use DES for alternative hashing methods?

I'm trying to understand how typical Linux distributions generate the password field for entries in /etc/shadow. I can't figure out what encryption algorithm is being used to produce the encrypted ...
2
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1answer
108 views

Eavesdropping a communication between a local application and the network

After some digging on the Internet, I've been unable to find a satisfying solution for my curiosity... Here's the thing : using a shell script, I've been able to obtain a list of IP addresses ...
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3answers
2k views

Are file permissions set in Unix/Linux effective in Windows or Any other OS?

Consider some files and folder in Unix/Linux OS which are configured for only read access by root, if the hard drive stolen, and used in Windows Environment, are these permissions are still effective? ...
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1answer
204 views

unix malicious scripts/ksh execution

I'm wondering whether my architecture poses a security risk. Details: The whole website is not ROOT owned but still, the APACHE user used instead has some pretty advanced permissions. I have a ...
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4answers
375 views

What mechanism enforces user permissions in Unix/Linux?

One of the core pieces of security in Unix/Linux systems is limiting privileges by user. For instance, certain actions can only be done by the root user. In theory, this can keep a malicious process ...
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2answers
212 views

What's the secure way to change UNIX permissions on a harcoded file often?

I'm writing a daemon that monitors something in the OS and flips execution permissions on a file in /run/ back and forth. The file has static contents and the file name is hardcoded in the daemon. I ...
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2answers
586 views

How is the available entropy in /dev/random calculated (or estimated)?

It seems (to a non-expert) that /dev/random is acclaimed to be useable as a source of pure random data. However, I am curious as to the analysis of the file /dev/random. /dev/random is a collection ...
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1answer
192 views

is root@localhost the same as Unix root with GUID = 0 and ID = 0?

Is a Mysql root user (root@localhost) the same as the computer root account (GUID = 0, ID = 0) ? I mean, is it the root which is executing the script? How can I know if the users are the same?
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0answers
1k views

Traditionnal DES scheme in Unix crypt function [closed]

In a security context course, we need to reproduce the old DES hashing scheme in the crypt program, on an old unix system. I am actually reading the crypt page on wikipedia: The traditional ...
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2answers
319 views

How a malware executes remote payload

Let's assume a malware was installed (on a UNIX-based platform) with some social engineering tricks. The original installed code itself may be benign, but the only malicious activity is that the ...
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5answers
1k views

Security purpose of asking admin password to mount partition on Linux

So I divided my 250GB laptop drive into 2 partitions and some swap. On the second partition which is an ext4 60GB partition I installed Fedora 17. On the other bigger NTFS partition I've got Win XP ...
2
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1answer
1k views

Is the mount manpage saying nosuid *is* secure, or is *not*?

I'm a bit confused about the description of nosuid in the mount manpage on this RedHat system I'm setting up: nosuid Do not allow set-user-identifier or set-group-identifier bits to take ...
5
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3answers
215 views

Could browsers improve security of stored passwords by using setuid?

On Unix-esque systems, Mozilla Firefox stores a users' preferences, web history and stored passwords in a set of files that are readible and writeable by that particular user. This makes sense: when ...
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4answers
515 views

Does UNIX have a dual approval mechanism?

Sudo and logging is used to keep administrators accountable. But is there a command/configuration that lets you enforce a dual approval type control such as the the "Two Person Concept"? (eg. Two ...
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2answers
293 views

unix config scanner / compliance checks

I'm looking for a tool, that scans unix operating systems for configuration issues. E.g. a script that finds PermitRootLogin yes in the ssh config file or with other words: a script that automates ...
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3answers
839 views

Is passing sensitive data through the process environment secure?

Recently I have been looking for the possibility to pass sensitive information from one process to another (at process startup time) without passing it through the command line or without using a ...
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1answer
325 views

Installing applications with different user accounts on linux

I have basic question about installing applications on Linux operating system, using the Oracle database as an example. When installing the Oracle database package, I created a user called ora112, a ...
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2answers
512 views

Security issues with an append-only log in UNIX

I'm going over past exam papers for a security module I'm taking at university and there is a question which I can't give a great answer for. As a security manager in a bank you are asked to ...
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1answer
4k views

what does it mean to be setuid root?

I am reading Tanenbaum's Modern Operating Systems 3e. He says "Suppose that the program being attacked [with malicious code] is SETUID root in UNIX (or has Administrator power in Windows). The ...
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2answers
322 views

Why superuser or administrator account should never locked?

Why should administrator or superuser account never locked regardless how many incorrect login attempts are made? What should be done instead to alert the staff to the attempted instrusion?
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1answer
249 views

What time do dictionary attack take on salted passwords?

I was reading that the designers of UNIX password algorithm used a 12 bit salt to modify the E-table of the unix hashing function (the DES). Supposing i have a system with 2^(24) users? Is that ever ...
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4answers
10k views

Netcat IP Spoofing

I am connecting to a server nc -v 192.168.0.1 1111 But I want to do IP spoofing because the server on 192.168.0.1 only accepting commands from 7.7.7.7. We are two friends, I am 192.168.1.1, and my ...
4
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1answer
4k views

Finding environment variables with gdb, to exploit a buffer overflow

I have to exploit a very simple buffer overflow in a vulnerable C++ program for an assignment and I am not being able to find the environment variable SHELL. I have never worked with BoF before, and ...
2
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2answers
271 views

vulnerable getlogin

I was reading "A taxonomy of Coding Errors" and I have a doubt regarding the point mentioned in C/C++ >> API Abuse >> Often Misused: Authentication(getlogin). I fail to understand the attack vector ...
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1answer
349 views

Can UNIX Domain Sockets be locked by user ID?

If I created a folder /tmp/me with permissions 700, and started a process under me that starts a listen socket under /tmp/me/socket. I currently assume that a connection to that socket originated ...
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2answers
1k views

What are the dangers of storing webserver temp files in the /tmp/ folder?

I have configured my first publicly accessible nginx server. I have configured it to use a /tmp/nginx folder to store temp files. This includes the body of http requests, proxy files etc. The /tmp ...
2
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1answer
128 views

What is a good method to report security breaches that are being used to actively spam?

I received an email the other day purporting to be from a bank I hadn't even heard of, so I decided to poke around. On some quick investigation, it looks like something has just latched onto some poor ...
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3answers
850 views

Making passwd/shadow files more secure

The passwd/shadow files in a unix-like OS contain sensitive info such as a user's password. In addition those files aren't necessarily secured: with a live CD we can access those files on the hard ...