Securing Linux systems and applications; understanding Linux security features.

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Question about something found in pcap [on hold]

Looking at a pcap, an SSH scan was performed and in the pcap, there was a line that said "Linux 2.6, seldom 2.4". I'm assuming linux 2.6 is the older version of linux, but what is seldom 2.4 and how ...
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35 views

How to adapt my exploit strategy when “00” is part of the targeted return address and the victim uses strcpy

I intend to exploit the following program on an x86 Linux machine with NX enabled (ASLR and stack canary disabled). The goal is to get a shell. //vuln.c #include <stdio.h> #include <string....
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1answer
12 views

Can software keyboard add security to decrypting FDE'd Drive

Having a LUKS Full Disk Encrypted Linux installation means that I need to input my decryption password before the Operating System can even start. This will require me to use a hardware keyboard on ...
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1answer
25 views

how to debug for DNS changing Maleware on (linux/android)?

So by opening an application/browser on my Android device, I found that it pops open a set of ads. I channeled a proxy through my laptop trying to track the first web site it connects to. Later I ...
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1answer
29 views

Metasploit INFILENAME

I am learning *MSF on Kali but I ran into a problem. I am trying a simple adobe_pdf_embedded_exe and when I set INFILENAME to something simple such as nutrition.pdf it cannot find the file, so ...
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45 views

What is the Linux Kernel attack surface? [closed]

What is the full Linux Kernel attack surface ? meaning what are the vectors through which untrusted or unprivileged access interacts with the Kernel. For instance, system calls are an attack vector, /...
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rdp connection with netcat pivoting

I want to connection from local computer to another local computer. I have 3 machine. for example A: 192.168.1.50 -> in local windows machine B: 50.3.52.110 -> linux server C: 192.168.5.25 -&...
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1answer
32 views

wpa_passphrase command encrpyting psk

Does the wpa_passphrase command turn an ASCII string into hexadecimal and what is the benefit of doing so? Is the psk sent in the header of packets? Can it be easy to sniff if it's in a string format? ...
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1answer
15 views

HPET effects on CSPRNG for Linux OS

HPET or High Precision Event Timer is a hardware built-in clock source available in most processors. I would use the computer to generate CSPRNG and do cryptographic operations. My question is: Is ...
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1answer
69 views

What is the best way to upload a file securely? [closed]

What is the best way to upload a file securely? My client is a .NET Desktop Application and server is Apache Tomcat running JSP Files, running on a Linux OS.
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1answer
43 views

Does stack (UNIX x86, x86-64, ARM) grow up or down, buffer overflow tutorials wrong explained?

when I read something about buffer overflows on the stack, the most or some tutorials show me examples about overwriting local variables (pointers) and then overwriting pointers in the global offset ...
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1answer
43 views

Why RedHat Linux has obtained separate FIPS 140-2 certificates for OpenSSL , NSS, Kernel Crypto API etc?

I am wondering why RedHat Enterprise has obtained separate FIPS 140-2 certificates for OpenSSL , NSS, Kernel Crypto API etc. Is it not enough to have FIPS 140-2 certification for only one ...
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2answers
24 views

Kali Linux: wrong kernel. What to do? [closed]

What does this mean : Unable to boot- please use a kernel appropriate for your CPU what do I have to do ?!
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0answers
14 views

Tboot TXT boot failed [migrated]

I have followed Fedora's wiki to setup launch control policy with TXT enabled. here is the link: http://fedoraproject.org/wiki/Tboot After Tboot issues GETSEC, it reboots without any error message. ...
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2answers
61 views

Very fast and efficient way to check that contents of the directory weren't modified

I need a way of determining whether contents of a folder containing some executable stuff have not been modified in any way a moment before I decide to execute the whatever is in it. Check every time ...
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0answers
35 views

Using hash of root password to encrypt files/folders (Debian 8 Linux)

I have an application that requires unattended decryption of files/folders. Would it be possible to utilize the hash of the root password to prevent an attack where a malicious user changes the root ...
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13 views

Differences between Intel TXT and Linux IMA

I understand that Intel TXT provides a Dynamic Root of Trust Measurement (DRTM). Does the Linux integrity measurement architecture do logically similar things? If not, what are the differences?
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How can extended file permissions (ACLs) be managed by Kerberos in Linux? [migrated]

Is it possible to have extended file permissions (ACLs) in Linux be managed (enforced?) by adding permissions authenticated by Kerberos?
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2answers
71 views

How secure is it to use secret directory names to share files on unix?

There is an old trick on unix systems to allow a non-root user to "securely" share files with particular other users. mkdir share chmod 711 share #others can traverse share, but can't list its ...
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3answers
457 views

How can I kill minerd malware on an AWS EC2 instance? [duplicate]

I have an AWS EC2 instance running RHEL 7.2 which seems to have been hacked by a BitCoin CPU Miner. When I run ps -eo pcpu,args --sort=-%cpu | head, it shows that there is a CPU miner that's taking up ...
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1answer
37 views

Are the Linux community/universe repositories significantly less safe then the main repositories?

If so what makes community/universe less safe? Is there less testing or is it simply less safe because more people could put malware in them.
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3answers
41 views

Node.js REST server running as root

I am building a REST API server using Node.js and Express, that will allow you to turn any Linux server into a NAS. I have several fileExec which basically spawns a shell and executes a BASH command (...
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1answer
3k views

Has malware ever been found in a package from a large Linux distribution and what is done to prevent this from occurring?

I am wondering exactly how safe are the Arch, Ubuntu, Mint and Manjaro repositories. What testing is done to ensure that a trusted user does not place a virus in a package, and how often?
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2answers
37 views

Why do websites still suffer from OS injections if by default web-servers are not assigned a shell?

So even if there is some poor php written which allows a shell_exec() and that someone disabled safe mode on it, what exactly are the risks? Do admins just change the default group or are most attacks ...
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2answers
38 views

DB Security from system admin perspective

I need some clarity in terms of Security involving Linux Admins and DBAs. Oracle DB on an Enterprise Linux server. I want to ensure none of the contractor team be able to tamper database and its ...
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1answer
40 views

Security implications of using SETCAP CAP_NET_RAW

In order to get around the 'problem' of applications requiring root privileges to run, I'm using: sudo setcap CAP_NET_ADMIN+ep "$(readlink -f /usr/sbin/app)" sudo setcap CAP_NET_RAW+ep "$(readlink -f ...
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1answer
105 views

What infection vectors is Trojan.Linux.BillGates usually delivered with?

I just discovered that my server is infected with Trojan.Linux.BillGates.G and is being used to launch DOS attacks. It surprises me as the server is kept up-to-date (CentOS/Tomcat/CouchDB) as much as ...
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1answer
32 views

How to best manage multiple applications using the internet with Firewall

Im not new too Linux (Ubuntu 14.x) however I must admit that I have never bothered with a Firewall until now. Im currently using Ubuntu's inbuilt firewall (UFW) with a graphical plugin (GUFW), which I ...
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3answers
86 views

Is it safe to manually patch security bugs in an outdated system, that is no longer supported?

How do I manually patch security bugs safely without damaging the system for information security purposes on my Ubuntu system that I am running on my Nook Simple Touch (2011 Nook)? I need to find ...
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1answer
27 views

On a Linux server, is it safe to store a script containing DBI credentials in the cgi-bin of the DocumentRoot?

I understand that (at least on Linux servers) the custom is to create a ScriptAlias from a cgi-bin directory located inside the DocumentRoot (i.e. /var/www/html/cgi-bin/) to a cgi-bin directory ...
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2answers
137 views

Is Qubes OS more secure than running a set of activity related VMs?

I'd like to skip the argument about Linux being more secure than Windows, and purely focus on the security boundaries between Host OS and VMs. Is Qubes OS theoretically more secure than say - Windows ...
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How are the disk encryption keys protected when a laptop is locked?

If you were installing such operating system as Ubuntu, you would have seen an option to encrypt your home directory or the whole hard drive with an AES 256bit cipher. When your laptop is totally ...
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3answers
94 views

Can I test my own network?

I'm currently trying to enter the field of information security and I was just wondering if there was anything barring me from testing my own network for security vulnerabilities? I only have a couple ...
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33 views

web view addjavascriptinterface exploit

I have been banging my head around this for almost 56 hours now (+/- a few that I took out to have a couple of naps and RedBulls) and have not been able to get anywhere with it so far. I am trying ...
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1answer
66 views

Does posting the technique I used to encrypt my Linux system make the encryption inherently less secure?

I recently encrypted my laptop, but I also wrote notes on how I did it and posted those notes online. The configuration is fairly complicated and, from what I can tell, also fairly unique. I did not ...
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2answers
53 views

When would group permissions be a security issue?

I frequently hear that 600 and 700 is recommended for security when possible before 660, 770. I'd like to understand the risk that 660, 770 would have that 600, 700 wouldn't.
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1answer
30 views

Does Dropbear support SSH key revocation?

I'm using Dropbear as an SSH server in my embedded system. I want to know if Dropbear supports SSH key revocation? If yes, how I can do it?
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1answer
94 views

Are the only people who can work in security those who were learning from 10 years old? [closed]

I'm a second years Master student in computer science. As time passes, the more my desire to work in computer security increases. I have many friends who are more experienced than I, who told me ...
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1answer
91 views

After a bufferoverflow does an attacker only have access to calls which are present in the library where the C code was compiled?

Or are there techniques to just get a shell? What I am interested in is if I have compiled some C code using only a small library with insignificant possible calls, does this restrict the attacker ...
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21answers
22k views

Hardening Linux desktop machine against people from my household

I am looking to make a clean install of a Debian system on my home desktop. To clarify, I am switching from Windows and wish to use it as my day-to-day home OS - I'm not going to be running any ...
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2answers
88 views

How to forget LUKS keys during emergency?

One day, while Alice is downloading some photos from Bobs server, the alarm goes off. Trudy came to steal all the data. Fortunately, the server is setup to shutdown upon server room alarm and has ...
4
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1answer
157 views

Protecting master password in memory

Assuming I want to enter master password only one time at the start of the program, how is this master password usually protected in memory after that? Is the encryption key after being derived from ...
3
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1answer
65 views

Where and how to create secret on embedded Linux system?

I'm using OpenSSL on an embedded Intel Edison (Atom Platform) running an Yocto Linux. I want to store passwords with OpenSSL on the device, but I don't know after which rules I should create the ...
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1answer
2k views

Does analysing Malicious code in gdb pose a security risk?

I have encountered a Malicious Shell-Code & i have ported the shellcode into a compatible C Code which can run the shellcode, i compiled it using gcc -fno-stack-protector -z execstack shellcode.c ...
2
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2answers
112 views

Finding a backdoor on a server?

Let's say I hire someone (freelance), for IT work on an Ubuntu server. The server has a good firewall, I run clamav, chkrootkit & rkhunter scans weekly, and I try to keep good practices. The ...
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2answers
70 views

Sorting hosts via open ports using NMap

I was tasked with running a NMap scan against our corporate network and compiling a list of only live endpoints. My issue is how to go about separating out the hosts via their open ports (printer/...
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1answer
5k views

I have the ability to run arbitrary Python code on the 'apache' user. What damage can I do?

So, due to bad programming on the part of one of my former colleagues, one of our internal web apps allows the user to upload and run an arbitrary Python file. This recently came to light via an ...
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1answer
88 views

Robots trying to login to Azure VM when SSH port is closed in manager

I have many robots trying to do SSH login in a Azure VM. In the resource manager SSH is disabled but attacker IPs are public, as you can see below, where I copy a log for auth.log (I have an Ubuntu ...
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2answers
68 views

How does allowing breaking grabs with keyboard actions pose a security risk?

While modifying the Gnome Tweak Tool I saw the following option which states that allowing breaking grabs with keyboard actions poses a security risk. How can it be a security risk?
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1answer
113 views

How to detect zip file encryption algorithm

As we know zip files supports a simple password-based symmetric encryption system and some vendors use other algorithms. I used the zipinfo command in Linux but it doesn't say what encryption ...