Securing Linux systems and applications; understanding Linux security features.

learn more… | top users | synonyms

3
votes
1answer
102 views

Does reinstalling ubuntu eliminates all existing rootkits/ malware/spyware/ virus etc?

If I do a fresh installation of ubuntu from an uninfected cd, will it remove all the existing rootkits/malwares/spywares/viruses etc if any ? Is formatting the hard disk required before reinstalling ...
3
votes
2answers
586 views

Restarting nginx with Jenkins or Phing - is it safe to allow Jenkins to run sudo without prompt for password

I am implementing the recommendations from Integrating PHP projects with Jenkins for my own PHP projects. I have created a jenkins user in my ubuntu 12.10 server. I used Phing as my build tool and I ...
3
votes
1answer
186 views

“WICKED” entries in the default nginx vhost's logs

I have a small VPS running nginx, and for a long time now (several months, since I rented it) it has been collecting weird entries in its default (listen 80 default;) vhost's logs: 109.x.x.121 - - ...
3
votes
1answer
693 views

Why ESTABLISHED,RELATED for INPUT only?

In many places and tutorials I see people add this line to their iptables: -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT And they do it only and only for "INPUT". What about OUTPUT and ...
3
votes
1answer
1k views

ARP-poisoning on wireless network - no packets

I've started working with ettercap and ARP-poisoning; however, I've sumbled upon some problems. I've executed the following command: ettercap -i wlan0 -w log -T -M arp:remote /192.168.1.254/ ...
3
votes
1answer
457 views

Two questions about learning Linux exploit development fundamentals

getting ready to delve into the technical world of vulnerability assessment, and I have two questions about where to find certain information. First, I plan on reading "Understanding the Linux ...
3
votes
1answer
652 views

Firewall rules to block unwanted protocols on given ports

Does somebody has an idea, that what kind of iptables/pf rule must i use to achieve this?: i only want to allow these connections [on the output chain]: on port 53 output only allow udp - dns on ...
3
votes
1answer
78 views

SNMPv2 and Community Security

When working with servers on the internet and doing monitoring is there any dangers using SNMPv2? I am working with observium and have the following: /etc/snmpd.conf com2sec readonly default ...
3
votes
1answer
107 views

What about AD2P vulnerability?

My goal is to create a simple one-way intercom using B Speech TX2 and B Speech RX2, an Audio2Bluetooth and Bluetooth2Audio converter. My question is, how secure is the audio(in my case voice) being ...
3
votes
3answers
323 views

Proper Linux user authentication through PAM aware applications

Currently I'm building an authentication system using Linux PAM for a python daemon process. It will need to authenticate remote users from a variety of front-ends against the local user list. ...
3
votes
2answers
205 views

Safely remove an expired PGP key file

since it's possible to recover a deleted file I wonder how one can safely remove a PGP key file (with linux's command line tools) so that it's impossible to recover it. Maybe some dd command? Searched ...
3
votes
1answer
290 views

What are some steps to take for securing a Linux server that aren't in this list of obvious ones?

Obvious things: Disable root login (rather, don't enable it) Secure SSH (no root login, key auth only, timeout after inactivity, whitelist users who can SSH in, etc.) IP Tables firewall whitelisting ...
3
votes
1answer
116 views

Do public keys make Kerberos more secure (RFC4556)?

We're using IPA to centralize our authentication and I found an option to add a public key for each user. After doing a little research I found this to be an extension to Kerberos 5, RFC4556. From my ...
3
votes
1answer
242 views

How to forward an specific FTP User to a Honeypot?

What I'm trying to do is to forward a specific FTP-User to a Honeypot, because the main server is for Shared Hosting and there's a lot of traffic, and I don't want to spend all the resources in ...
3
votes
2answers
157 views

How do shared hosts protect different sites?

I host all my websites from a single Linode VPN, and am about to sell some limited space of my Linode to a friend to host their new blog (it's going to be a simple wordpress blog). It'll simply be ...
3
votes
3answers
134 views

Protecting against Firewire DMA vulnerabilities in Linux

I know there have been questions on this in the past but they all seem quite outdated, or not that specifically relevant. I need to use a 1394(Firewire) connection, however am concerned with possible ...
3
votes
0answers
73 views

Deny Skype video access in Linux? [closed]

I have noticed that despite having configured Skype to not access video, during startups it continues to access the webcam momentarily. Skype is not a user, so I am unsure how to modify its ...
3
votes
0answers
104 views

Apparmor policies w/ subprocess failing [closed]

Can anyone possibly explain why Apparmor is not picking up profiles for sub-processes of a process? Right now we use God to launch an unstoppable Ruby process (in this case it's /usr/local/bin/remote) ...
2
votes
3answers
416 views

does switching to linux remove existing computer virus

if you change from a malware/spyware infected windows setup to a linux setup will infections migrate to linux if they were on the computer? (when you are hacked/infected is it the op system that is ...
2
votes
2answers
241 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 ...
2
votes
3answers
224 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 ...
2
votes
2answers
605 views

How to protect Linux partition from access from Windows partition?

In a dual-boot environment (windows? and linux mint 15) What would be best best way to prevent access to the linux partition(s) when the system is booted into windows 7? The goal would be to ...
2
votes
2answers
235 views

Can unencrypted keys & logins be kept out of program memory?

No matter what technique is used to store encryption keys & logins, it seems that all roads lead back to program memory (as far as I know), as an unencrypted version of the keys & logins will ...
2
votes
2answers
258 views

Can the `system` function pose severe security threats on a shared hosting server?

I recently bought an account from a shared hosting company and I needed the php system function to be enabled for one of my projects. So I created a ticket and asked them to enable it. This is what ...
2
votes
2answers
87 views

What kind of privacy leakage do stuff printed to stdout pose?

1- When a program outputs to stdout, is that normally logged anywhere else? 2- When is it an issue to make a command verbose in printing to stdout instead of working quietly or redirecting to a file? ...
2
votes
3answers
808 views

discover virus or spyware under Linux

I suspect to be the target of very skilled hackers. 5 or 6 years ago I found spyware on my Linux webserver, it was lkm masked as ppp_deflate module with md5 hash hijacked. I mean with the same md5 ...
2
votes
2answers
525 views

Allow apache to write to users' .ssh dir's

I know the title is just baiting the "your setup is insecure", but allow me to explain. I'm working on an application which aims to allow clients to rsync over SSH to our server. We need a web ...
2
votes
2answers
1k views

Decrypt from cipher text encrypted using RSA

I am sniffing a client side application traffic and I found some encrypted data. I am not able to decrypt it. Information which I have is Public Key: ...
2
votes
1answer
114 views

Trust linux images burned from untrusted systems

For securitys sake I'm assuming my system is successfully compromised after a targeted and/or non-targeted attack. I've downloaded some linux images and burned them to do a re-install. Since I can't ...
2
votes
3answers
740 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 ...
2
votes
4answers
140 views

Protecting IP on a remote server

Apologies in advance if this question is a bit vague. I just joined a stock trading group. A guy set up a server for me, and it's racked in their building. I ssh into it, and run my algo remotely ...
2
votes
2answers
197 views

How to protect source code that resides on virtualbox web server which starts at boot?

I installed CentOS 6 on a 3gb virtualbox disk. It hosts a web server which starts automatically when the OS boots. No user login required. When it boots, it is given an IP and the host machine can ...
2
votes
3answers
112 views

Could an Encrypted VG/Image compromised?

I mean if I encrypt my ""full system"" so that everything (besides the /boot) is in an encrypted VolumeGroup (Linux). So I store my /boot on a flash drive, thats always next to me. Q: can the ...
2
votes
3answers
1k 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 ...
2
votes
2answers
239 views

Encrypting Backups on Linux

I'm working on an automated backup solution to protect my files on my Linux servers. However, I'm not sure about how to securely encrypt the resulting archieves. I am using 64bit linux, and I am ...
2
votes
1answer
180 views

Bypass va_randomize_space and stack-protector

Is a program compiled with the GCC -fstack-protector option and running in a Linux environment with the va_randomize_space kernel variable set to 1, totally protected against buffer overflow attacks? ...
2
votes
2answers
182 views

Is it possible to boot into root's /bin/bash on a LUKS encrypted device?

I have to check the possibility of case mentioned in the title. An average Linux could be booted up into root's terminal directly without authentication by modifying kernel boot parameters. I'd like ...
2
votes
2answers
3k views

IPTables DDoS protection working with per client IP address counter AND UDP

I am looking to protect LAMP server with a software, which will detect above average number of requests from single IP numbers (in this case DNS queries), and add these hosts to IPTables deny chain. ...
2
votes
3answers
998 views

Open Source Vulnerability Scanner

I'm looking for an open source vulnerability scanner that I could install on one of my machines and point to all my others. Ideally, I'd be able to configure a nightly scan where all of my other nodes ...
2
votes
3answers
130 views

How to detect the “Hello packets” sent by a wifi enabled smartphone

Actually I have a case where I should able to detect the mobile phones and get some data about the device available in my network range without connecting to the network. I have seen somewhere that a ...
2
votes
1answer
166 views

Consequences of using -s and -d arguments in iptables

We are studying iptables for a Computer Systems Security course. We are confused as to what happens when the -s and -d arguments are both used in the same rule, such as: iptables -A OUTPUT -s ...
2
votes
2answers
1k views

NSA RHEL5 Checklist

The NSA has came up with the "Guide to the Secure Conguration of Red Hat Enterprise Linux 5" (http://www.nsa.gov/ia/_files/os/redhat/NSA_RHEL_5_GUIDE_v4.2.pdf) I have read through this guide and it is ...
2
votes
2answers
574 views

up2date tools for security audit linux / centos

I'm setting up a new CentOS 6 server and am looking into some security audit tools to validate my configuration and to point out weak spots in the server. There are a lot of non up2date tools out ...
2
votes
3answers
2k views

Writing a sample virus (not harmful)

I don't know if such a question is allowed on this site, sorry if it's not For educational purposes I am asked to write a small virus running on Linux, which should just be able to inject itself into ...
2
votes
1answer
22 views

bin_random_table and RANDOM_BOOT_ID

The Linux kernel has a few sysctrl's related to random devices packaged in a bin_random_table (http://lxr.free-electrons.com/source/kernel/sysctl_binary.c?v=3.2): static const struct bin_table ...
2
votes
2answers
252 views

Apparmor system-wide security — white-listing

I want to only white-list applications that can run on my system using Apparmor, I know it is used to confine applications/programs based on their path names, but what I need is to contain those ...
2
votes
1answer
146 views

Preventing access to file for process running as root

I have a client with a legacy application running on RH 3 (=the latest version supported by app). There is a process that has to run as root (and not in a chroot environment). I need to prevent this ...
2
votes
2answers
623 views

What are the implications of including binary blobs in the Linux kernel?

According to this there are compelling reasons for caution when installing obfuscated binaries. Knowing this, how can running binary blobs as a part of the Linux kernel be acceptable from a security ...
2
votes
1answer
179 views

How are IaaS Virtual Machines Isolated?

I am currently examining Hypervisor firewalls for my graduate thesis, but I unfortunately don't have a lot of experience with IaaS environments. How are IaaS Virtual Machines network isolated from ...
2
votes
1answer
452 views

What is the actual value of disabling remote root login using ssh?

I have read the answers regarding why you should disable remote root login, but there is something nagging me. Assume this: Scenario 1: Remote server A. Remote root login disabled. Password ...