Securing Linux systems and applications; understanding Linux security features.

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4
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2answers
942 views

Is GPG suitable as part of a password manager and generator?

I assume that GPG is very strong to crack, guess, etc. Since I have confidence in GPG, would it be appropriate to use my GPG key as the master key for a password manager or generator?
2
votes
2answers
5k views

Test firewall rules (Linux)

I have a question about how to test the firewall rules. To be more specific, for academic purpose I have to set up a machine which will accept all kind of packets o a specific interface. I added an ...
1
vote
3answers
516 views

How to Detect Zimbra Sniffing Trojan

I am a sys admin of our system, we are running zimbra as email server in our environment. I got the following message from the CEO. "Everytime I send or receive an email - I get a SPAM ads a few ...
2
votes
1answer
242 views

tshark - dump the data section

As the name suggests, im trying to dump the data section of the packet, man would suggest that its something like tshark -r file.pcap -t fields but im not having any luck
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3answers
1k views

Best practices for firewall hardware

I'm planning to implement a linux based firewall/router with at least 6 x 1Gb NIC's (network with ~300 computers/server with >=8 VLANs) Can anybody recommend hardware best practices (reference to ...
0
votes
1answer
653 views

How configure tomcat 7 SSL to use AES-NI?

My server has AES-NI and I would like tomcat 7 to make use of this but I am not really sure how to make that happen or where to even start looking. I am quite familiar with tomcat administration, and ...
0
votes
2answers
191 views

Tracing root compromises

In regards to the following: 0day Linux/CentOS SSHd Spam Exploit — libkeyutils.so.1.9 SSHD Rootkit There apparently seems to be a bunch of redhat server being backdoored via a library. Does ...
1
vote
1answer
81 views

Does pppd encrypt traffic?

There is pppd program that can be used to create point-to-point conections over various channels (including other network). It supports authentication and compression. But does it encrypt traffic or ...
4
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2answers
3k views

Need advice on linux server being hacked

I'm currently trying to find out how one of our centos servers was compromised. We were experiencing malware on our sites. After searching I finally found the malware injecting into the sites. As it ...
12
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5answers
2k views

Apache/Linux server, DoS attack from own IP

I have an unusual problem I've been trying to diagnose for a while: It's about a Debian server running a custom compile of apache 2.2 with PHP, Red5, MySQL 5.5 (standard binary), sendmail (distro ...
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4answers
1k views

Why do I need both root password and user password in Fedora Linux?

I am just now installing (for the first time) a shiny new Fedora 18. I set up a strong root password, installed the whole thing. Now it is asking me to create a user account and a password is ...
5
votes
1answer
158 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 ...
0
votes
2answers
316 views

Is there an easy way to secure Apache on debian?

I run an Apache webserver with lots of PHP-sites of several customers. I tried install apache-mod_security2 after this (german) tutorial that is using these rulesets: ...
3
votes
3answers
855 views

Restrict access to a specific directory on Linux

I want to limit access to a single directory on the hard disk (log files) to few processes (log files for a single process for example). All processes run under the same user, so file system access ...
5
votes
3answers
3k views

Wine or sandboxie as sandboxes

I'm looking for a sandbox for Windows. I've looked at sandboxie but I don't know if it delivers what it promises. Is it actually safer to run programs inside sandboxie ? I know a full-blown VM could ...
1
vote
1answer
99 views

set uid for reboot binary & pm-suspend : security hole?

I think all the question is in the title : For the use of my laptop to be more convenient I made a chmod 4755 to /sbin/reboot and /usr/lib/pm-utils/pm-action so I don't have to make a 'sudo' before ...
5
votes
3answers
473 views

Live Linux which does not mount any hard drive in the computer

I am searching for a Linux System which runs from a CD and does not mount any hard drive of the computer. I want to prevent any possiblity to write something on the hard drive of the computer and on ...
0
votes
1answer
1k views

Retrieving saved password from Firefox on Linux [closed]

I know there are ways to get the cookies from browsers in Windows and retrieve and decrypt saved passwords from them. Is there a similar way to do so on CentOS?
7
votes
2answers
7k views

Is it possible to use the aircrack-ng tool to crack a WPA2 Enterprise network?

is this tool (aircrack-ng) capable of cracking into a WPA/WPA2 Enterprise network? This tool has major success cracking the passwords of WEP/WPA networks. If it can, how, but if not, is there another ...
1
vote
2answers
267 views

Linux kernel 3.2 syscalls

Just trying to get the assembler instructions for <__execve> of the code below because i want to build the shell spawn opcode list: #include <stdio.h> int main() { char *happy[2]; ...
6
votes
2answers
212 views

Process authentication for Linux

Is there any possibility to authenticate a running process in Linux to be sure that this is the original/right one? I know that an Linux operating system is only that secure like the way you use it. ...
0
votes
1answer
160 views

Different types of segmentation faults in Linux [closed]

In Linux, when the NX-bit triggers the segmentation fault seems to be "error 15", whereas a more typical error, such as attempting to read from invalid memory, results in "error 7", (seen from dmesg ...
5
votes
2answers
3k views

Pitfalls of SSD encryption

Encrypting an SSD is a process that is sometimes warned should be done with caution. E.g. http://en.gentoo-wiki.com/wiki/DM-Crypt_with_LUKS mentions how the SSD may keep hidden space used for wear ...
7
votes
2answers
612 views

Filling the disk with random data prior to encryption?

Filling the disk with random data prior to encrypting it will supposedly make it harder for the attacker to perform any cryptanalysis. Most sources seem to state this is because it will be harder for ...
11
votes
1answer
435 views

Slot machine segfault: what can we determine?

We walked into a casino and saw this near the entrance. I don't have a specific question, but is there anything that would be interesting to share and explain from the image?
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.
20
votes
4answers
8k views

What can an attacker do with Bluetooth and how should it be mitigated?

What are the security risks of Bluetooth and what technologies and best practices should be used to protect my device? What can an attacker do once a malicious device is paired with mine? ...
3
votes
2answers
790 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
4answers
434 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 ...
0
votes
3answers
161 views

How to retrieve a site whose server is running Linux

I'm struggling to find a way to retrieve through Google a list of sites having Linux as their server operating system. Actually, I'd like to be able to test the following command: nmap -O ...
2
votes
2answers
195 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 ...
3
votes
2answers
268 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 ...
2
votes
1answer
120 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 ...
1
vote
1answer
102 views

How to forbid one directory only in TOMOYO (2.5)?

(For example) I want to restrict write access to /home/backup from anybody, except a particular backup script. (To protect from accidental deletion.) For this, I suppose, it is enough to have two ...
3
votes
1answer
202 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
321 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 ...
1
vote
3answers
193 views

Protect linux kiosk display

We use a small computer with linux attached to a big tv to display some data to the public. Normally, there is no keyboard connected. When a keyboard is connected at boot, we start the configuration ...
5
votes
5answers
555 views

HOWTO : Email encryption in a browser

I have read about encryption and I think it's a good idea for me to encrypt my email. I run ubuntu 12.10 and use Firefox for browsing. In my quest for learning how to use gmail/hotmail to send and ...
4
votes
2answers
1k views

Impact of Mathew Garrett's Secure GRUB Bootloader on UEFI Secure Boot

My eyebrows rose with Matthew Garrett announcing his Secure GRUB Bootloader less than three hours after no longer being a Red Hat employee. This work and its impact on the trust chain design of the ...
0
votes
1answer
225 views

SSH Log: “Accepted password for user…”

I have only port 29999 open for SSH connections. But in the log file I see entries like this: Accepted password for user1 from 190.101.200.100 port 55805 ssh2 saying that a connection was accepted ...
3
votes
1answer
374 views

How do I configure Terminal Server (and clients) for use over untrusted Wifi networks?

Suppose a client wants to directly connect to Terminal Server exposed to the Internet, without a VPN, ... what software & settings is needed to properly protect against WiFi based attacks? ...
12
votes
4answers
428 views

How to safely synchronize time over Internet?

All modern OS now keep accurate time by regularly synchronizing time over an untrusted network - Internet. Could an attacker conducting a MITM attack, influence or change the time of a computer while ...
9
votes
1answer
15k views

TCP Peer unexpectedly shrunk window messages in dmesg log

We get quite few messages like these in our dmesg log on various servers: TCP: Peer 0000:0000:0000:0000:0000:ffff:d431:5861:56369/80 unexpectedly shrunk window 2522304441:2522312601 (repaired) TCP: ...
2
votes
1answer
143 views

Why must VMX instructions trap?

What would happen if each of these instructions didn't trap into VMX root when executed in VMX non-root? INVEPT, INVVPID, VMCALL,VMCLEAR, VMLAUNCH, VMPTRLD, VMPTRST, VMREAD, VMRESUME, VMWRITE, ...
1
vote
2answers
225 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 ...
2
votes
1answer
185 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 ...
3
votes
3answers
668 views

Online security check via command line

My scenario is that I have a VPS with Apache (mostly for development of my own projects) accessed via SSH; and I time to time I would like to do a quick check just to be sure that there's no potential ...
97
votes
8answers
5k views

Attacking an office printer?

I did an nmap scan on an advanced office printer that has a domain name and is accessible from outside the corporate network. Surprisingly I found many open ports like http:80, https:443, and ...
3
votes
2answers
758 views

Possible implementations of networked+encrypted filesystem

Is it possible to implement scheme where remote server just share its filesystem (or resizable container file in it) and it's locally encrypted and mounted? And what is best practical method? (On ...
3
votes
1answer
81 views

auditing mod security rule sets

Is there a audit system that can help me try my strings? Such as user agents, post/get data, a simple way to test general sql injections to see how my rule sets hold? I know with fire fox I can ...