Securing Linux systems and applications; understanding Linux security features.

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2
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1answer
313 views

How does SELinux affect the Linux Kernel networking stack?

I'm interested in how SELinux effects the processing of packets through the networking stack. I've found the following questions and answers: Network policies under AppArmor/SELinux Filtering ...
0
votes
1answer
55 views

is return-to-libc attacks possible Now?

I'v read that to make a successful return to lib-c attack, the attacker should store the address of the command (for example "bin/sh") in stack exactly after the return address to 'system' function ...
-1
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2answers
46 views

How can I detect mode interface of other machine is promiscuous [closed]

I have a project that is to protect my box from attack man in the middle arp poison. I should detect if interface mode of other machine is promiscuous. I must write script python or command linux.
2
votes
1answer
88 views

How to find stack pointer for overflow bug?

I've read that stack usually starts in same address so the attacker may guess the starting point of the buffer to overflow. This is necessary to know this address to make the malicious code run. I ...
0
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0answers
14 views

I Use Precompiled Open Source Software. Is There a Backdoor? [duplicate]

I'm new to Linux world (3-4 months with Linux). But I did compile some programs from source and had one failed attempt to compile a custom Linux kernel. One thing that I'm wondering about is the ...
4
votes
1answer
89 views

Is symlink race a very common vulnerability in UNIX systems

As far as I know, when I am creating a new file or directory in a directory that can be written by multiple users (and thus an adversary can have made a symlink there), the only way to protect myself ...
0
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1answer
175 views

Why my files that Encrypted with EFS in Windows 8.1 shown in Linux ubuntu?

i Encrypted my files with EFS in windows 8.1 so i logged in ubuntu and without any warning , its shown my files actually not Exactly the file but shown the path of file and the name and i can ...
0
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0answers
146 views

Discovered unexplained large salted files in root folder on Linux, possible keylogger?

So I had Linux Mint running on my laptop, just installed it a month ago. It has a small hard drive, just 160gb, and I noticed shortly after installing the system, it ballooned to 80-some gigabytes ...
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0answers
33 views

unable to execute shellcode,which is place on stack [duplicate]

I am trying to execute the shellcode to spawn an "sh" shell. I have taken shellcode as command line arguement,copied it to stack and tried to overwrite the return address of main function with the ...
3
votes
1answer
134 views

OpenSSH downgrade attack

I have tried to implement a downgrade attack against the SSH protocol as the first steps (encryption protocols exchange) are not signed, as per RFC4253. The idea is to intercept (mitm) these steps and ...
2
votes
3answers
612 views

Can I use 777 file permissions inside server virtualisation (that only I have access to) without worry?

For this question, please assume I have followed every possible security measure to secure my Linux server. Only I have access to the web server via one open SSH port. If there are security issues ...
2
votes
3answers
151 views

Is it okay to only use username/password to secure an admin page for moderating a website?

Is there a standard practice to securing an admin page for an application written in angular and nodejs or just in general? The admin page would approve/ban users and moderate comments. Should it be ...
1
vote
1answer
62 views

NMAP Scan Returns Odd OS Detection [closed]

I am new to NMAP but I was using it to troubleshoot some issues I have been having. I ran a scan on a device and I know the device runs some sort of Linux or Ubuntu OS and I was attempting to figure ...
1
vote
1answer
102 views

Is End to End encryption possible for all servers across the whole infrastructure?

Running into a possible situation where a client I am working with is requesting that all data that leaves the servers should be encrypted and here, we are talking of hundreds of Linux servers ...
4
votes
1answer
46 views

What security problems does copying .Xauthority to another user present?

If I want to use a GUI application with another user (example: webbrowser), I can copy the .Xauthority file to that given user's home then I can "su - user" and start the GUI app. Question: but what ...
4
votes
2answers
139 views

Is there a way to check for “hollow” processes, or malware hidden within “normal” processes

I recently came across an article on the The Verge, which centers around the concept of commercial malware production and how it's used around the world. The article introduced me to a number of ...
1
vote
2answers
396 views

How to change default cipher in GnuPG on both Linux and Windows?

How can I change the default symmetric cipher used by GnuPG from CAST5 to another? I'm using GPG4Win on Windows, but would also be interested in a solution for Linux.
2
votes
2answers
85 views

What are the security risks in leaving 'sudo' inside my production code?

I have a script that can only run successfully with root permissions But in development it's really hard to run with root permissions (in my development environment) so I add 'sudo' when ever it's ...
1
vote
2answers
989 views

Tails OS for Android and PC?

Can I use Tails OS on a USB-stick on both an Android tablet and a PC, or do I have to have two different versions? Would I have to go into the BIOS to make this work?
1
vote
1answer
86 views

Read SSL Certs with user process

I am running my own server, on which I have different services (Nginx etc.). All these (internet) services are / should be secured with SSL (offcialy signed). The key files / certificates are located ...
0
votes
1answer
102 views

php- is my code secured enough to protect from remote command execution when using shell_exec()?

I am using shell_exec function on the following variables to execute commands on the shell: fname (characters only) fpack(characters only) email (a valid email address) My code is: <?php ...
4
votes
1answer
121 views

Linux/ssh - Forensic question

In a Linux terminal, I made a ssh connection from A to B and I used commands to read some files stored in B. Then I disconnected and I closed the terminal. Is it possible to find on A, informations ...
0
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1answer
49 views

Are paravirtualized drivers a security risk?

Below is a copy of my answer that I gave in some other thread (Would running VMs inside of VMs be a more secure way to study viruses, etc?) about a topic of security of nested virtualization. I would ...
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3answers
335 views

Can I do hacking using Windows OS? [closed]

I have searched the web a numerous times but haven't found an explicit answer to my question. I've studied (at school and on my own) computer networks for 2 years, doing active programming for 4 years ...
1
vote
2answers
143 views

How to test the php vulnerability CVE-2014-3515

How to test if I'm vulnerable regarding CVE-2014-3515? My vendor supplied me with a patch and verified that it installed however I would like to verify that I am no longer vulnerable. My vendor ...
5
votes
2answers
135 views

Four eyes authentication for command execution on Linux. (OS level) [closed]

I reached the end of the internet with no success, so now I turn to you guys. What I'm after is a way to implement four eyes principle on the OS level for certain commands in Linux. Example : The ...
36
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3answers
75k views

What is the difference between authorized_key and known_host file for SSH?

I am learning basics of SSH protocol. I am confused between the contents of the following 2 files: ~/.ssh/authorized_keys: Holds a list of authorized public keys for servers. When the client ...
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0answers
131 views

open ports on a netgear N-150 router; disable SPI firewall? [closed]

How do I open all ports? At least internally, for LAN traffic from 192.168.1.x to 192.168.1.x I want all ports open. Even if it creates a security problem. thufir@doge:~$ thufir@doge:~$ nmap -p ...
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votes
3answers
222 views

How to determine if someone is scanning my server?

How is possible to determine if someone make requests with tools for pentesting? Is there any linux command?
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0answers
137 views

Man in the middle attack, bridging wlan interface to virtual wired interface at0

I'm trying to execute a Man in the Middle attack on my mobile phone, I have two wireless cards, one inbuilt in the laptop, running AR9285 atheros drivers, the 2nd is an Alfa AWUS036NHA card with an ...
1
vote
2answers
142 views

Roommate Frequently Hacked — How Do I Protect My Network/Devices?

If you absolutely had to share a network with a user who had a very lax approach to security and was frequently hacked (1-2x month for over a year now), what might you consider doing to secure your ...
1
vote
1answer
53 views

Can sshd block IPs with failed attempts or is a tool like denyhosts or fail2ban necessary?

I am only indirectly familiar with denyhosts (and only just discovered fail2ban) and they certainly seem like worthwhile tools. However, after looking through the options for sshd_config I am trying ...
5
votes
1answer
139 views

Explain the last part of how Mitnick hacked Tsutomu Shimomura with an IP sequence attack

I was reading up on why TCP ISNs need to be randomized, which led me to this write up by Tsutomu Shimomura. I understood how IP address spoofing and predicting the ISN helped the attacker establish a ...
0
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2answers
93 views

Safe to use setuid with absolutely no input?

I have a shell script which syncs some files from a remote source and I have a pretty typical HTTP server set-up. There is a user who owns the files served by the HTTP server and a user which runs the ...
0
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0answers
28 views

Improve the security of a website implementing the least privilege principle [duplicate]

I am a beginner and I am trying to program a secure website to improve my skills and knowledge. I am under Linux and I am using LAMP with php. My website is similar to a social network so people will ...
0
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0answers
111 views

Improve the security of a website implementing the least privilege principle

I am a beginner and I am trying to program a secure website to improve my skills and knowledge. I am under Linux and I am using LAMP with php. My website is similar to a social network so people will ...
4
votes
3answers
1k views

Is there any way to block LD_PRELOAD and LD_LIBRARY_PATH on Linux?

Preferably with a vanilla Linux kernel i.e. not using SELinux or GrSecurity? Lately there has been a case of in-the-wild UNIX server malware: ...
3
votes
1answer
377 views

My sendmail started sending spam; what is causing it to do so? [closed]

Today my sendmail service started sending e-mail to various addresses. /var/spool/mail: From MAILER-DAEMON@noxcommunity.com Fri Jan 30 22:15:30 2015 Return-Path: ...
9
votes
1answer
1k views

Is Java vulnerable to glibc GHOST Vulnerability in Linux?

I see on our RedHat Linux platform that "java" process has dependency over glibc library: [root@hpproliant1 ~]# ldd /usr/bin/java linux-gate.so.1 => (0xffffe000) libpthread.so.0 => ...
1
vote
2answers
484 views

How should I deal with adware in chrome on ubuntu?

I use chrome (but also have firefox) on ubuntu 14.04 32-bit. Recently I started getting popups from 'softwareupdaterlp.com'. I had the sense to realize it was not legitimate and I didn't click install ...
17
votes
3answers
2k views

Why doesn't Linux randomize the address of the executable code segment?

I've recently been learning about how ASLR (address space randomization) works on Linux. At least on Fedora and Red Hat Enterprise Linux, there are two kinds of executable programs: Position ...
0
votes
1answer
55 views

Bogus HostName Causing Suspicion of Man In The Middle

I have servers on a LAN reporting my laptop with a bogus hostname. This is making me suspect a man in the middle attack. Here are some details: From an Ubuntu Linux 14.04 laptop, I logged into an ...
0
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0answers
145 views

Is there any method to prevent/trace ddos attack?

I have a debian linux server which run a few online game services. I have some competitors in this area and i think one of them is behind the ddos attacks. I have full access to the router, so I set ...
6
votes
2answers
5k views

Best method to sandbox X applications in ubuntu

What's the best way to sandbox an X application like firefox or thunderbird in ubuntu (going into the direction of what qubes os does, but only for single applications)? I know there are many ...
2
votes
2answers
62 views

Linux Repo Security

Can a registered 3rd party repo spoof critical packages (e.g libc6) and have them installed on apt 'upgrade' operations? What are the best ways (configuration) to help manage 3rd party repos to ...
3
votes
1answer
192 views

What is a secure mechanism for wireless communication between Android and Ubuntu?

I have come across a few Android apps that provide various features for communicating with a desktop machine (sending text or typing in one direction or another, controlling the desktop pointer with ...
2
votes
1answer
105 views

How does the Samba misconfigured '/etc/passwd' file security bypass vulnerability work?

I just found this vulnerability on http://www.securityfocus.com/bid/36363/references, which affects several samba server 3.0.xx. Can anyone explain more about this vulnerability? How this bypass ...
1
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2answers
117 views

About SHA1 in default Disk Encryption in Linux

Link to the Thread: Recommended options for LUKS (cryptsetup) I wonder what's the exact difference between SHA1 and SHA512. I know that SHA512 has a longer key but I've read that it doesn't matter ...
5
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2answers
1k views

Security of Linux Full Disk Encryption (Ubuntu / Mint) -insecure?

I'm wondering, why is Ubuntu and Mint using SHA1 for Full Disk Encryption? I heard several times that SHA1 shouldn't be used anymore because it is weak and it could be cracked. Could you guys ...
0
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0answers
32 views

Bruteforce with Hydra [duplicate]

I'm trying to use a Hydra script in the following scenario on localhost and Linux: After web form login, my app redirects to another page with header(Location: internalpage.php) I use this syntax ...