Security is not a product, but a process.

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16
votes
2answers
3k views

Auto-booting and Securing a Linux Server with an Encrypted Filesystem

I'm setting up some new Ubuntu servers, and I'd like to secure the data on them against theft. The threat model is attackers desiring the hardware or rather naïve attackers desiring the data. ...
14
votes
3answers
2k views

Log every command executed from root

I want to give access to my root server to an external system administrator, but i want to be sure to double check what he is doing to my server, e.g. copying data i don't want them to do and so on. I ...
50
votes
11answers
10k views

Does changing default port number actually increase security?

I have seen advice saying you should use different port numbers for private applications (e.g. intranet, private database, anything that no outsider will use). I am not entirely convinced that can ...
14
votes
2answers
971 views

how do i perform root actions from non-root account?

I want to be able to restart services from a php-script. running under the www-user account. What's the preferred way to perform these actions? I recon I can place create a file with que'd commands, ...
26
votes
8answers
2k views

What should I do about a “misbehaving” user?

What should I do about this user? The user is: Downloading pornography Attempting unauthorized access Running hacking software Sending unsolicited email Installing software / tampering with the ...
42
votes
2answers
5k views

Why do I have to edit /etc/sudoers with visudo?

I've noticed that the sudoers file and cron config files act in a special way compared to other config files on Linux. They need to be edited with a special wrapper rather than any text editor. Why is ...
14
votes
7answers
10k views

How would you send syslog *securely* over the public Internet?

So I've got a few servers which I'd like to log centrally but obviously I don't want to pass the data insecurely over the internet. I've tried syslog-ng but can't make it work in a secure way, a ...
4
votes
2answers
3k views

SYN Flood Advice

Today I've been dealing with a server suffering from what looked like a SYN flood attack. It was a bit of a rush to get the site back online, so we did these three steps to bring the service back to a ...
11
votes
1answer
20k views

How to disable SSLCompression on Apache httpd 2.2.15? (Defense against CRIME/BEAST)

I read about the CRIME attack against TLS Compression (CVE-2012-4929, CRIME is a successor to the BEAST attack against ssl & tls), and I want to protect my webservers against this attack by ...
13
votes
4answers
3k views

Is iLO safe enough to be hung on the WAN

I am wondering if iLO is safe enough to be hung on the WAN, I looked for some articles but could not find any ? How do you guys secure iLO ? Do you put it behind a firewall ? Would you use a ...
3
votes
2answers
885 views

Read access control with Mercurial and Apache

I've set up Mercurial via Apache (hgwebdir.cgi). I would like to have the same functionality as when using Subversion and AuthzSVNAccessFile, in which I can restrict which user has read or write ...
1
vote
4answers
1k views

Is there a static, server-side vulnerability/virus/malware/BadThings™ scanner?

We run a shared hosting webserver with the usual LAMP stack. It is up and running since many years ago (uhm, Apache-1.3 and PHP-3 days?) and went through many iterations. We strive to have good ...
2
votes
3answers
718 views

bind9 in a chroot jail - necessary or not?

I always used to keep my bind9 installation in a chroot jail. Now I upgraded my vServer and have to install bind9 over again. Due to the virtualization solution my hosting provider uses, I cannot ...
45
votes
5answers
106k views

How do I grant start/stop/restart permissions on a service to an arbitrary user or group on a non-domain-member server?

We have a suite of Windows Services running on our servers which perform a bunch of automated tasks independently of one another, with the exception of one service which looks after the other services....
69
votes
10answers
80k views

Dealing with HTTP w00tw00t attacks

I have a server with apache and I recently installed mod_security2 because I get attacked a lot by this: My apache version is apache v2.2.3 and I use mod_security2.c This were the entries from the ...
29
votes
8answers
3k views

Securing PHP webservers

PHP applications have a reputation for higher than average security problems. What configuration techniques do you use for making sure the application is secure as possible? I'm looking for ideas ...
56
votes
4answers
12k views

How to handle security updates within Docker containers?

When deploying applications onto servers, there is typically a separation between what the application bundles with itself and what it expects from the platform (operating system and installed ...
32
votes
8answers
6k views

What are best practices for managing SSH keys in a team?

I work with small teams (<10) of developers and admins with the following characteristics: Most members of the team have >1 personal computer, most of which are portable Team members have access ...
22
votes
15answers
27k views

Is there an alternative to /dev/urandom?

Is there some faster way than /dev/[u]random? Sometimes, I need to do things like cat /dev/urandom > /dev/sdb The random devices are "too" secure und unfortunately too slow for that. I know that ...
47
votes
19answers
3k views

The IT Manager is Leaving - What do I lockdown?

The IT Manager may be leaving, and it's possible that the parting of ways may not be completely civil. I wouldn't really expect any malice but just in case, what do I check, change or lock down? ...
19
votes
22answers
7k views

Why are Linux-based operating systems considered safer than Windows? [closed]

I hear that Linux-based systems are better for security. Apparently they don't have viruses and do not need antivirus software. Even my university claims this - they refuse to have Windows on their ...
50
votes
5answers
15k views

How to decide where to purchase a wildcard SSL certificate?

Recently I needed to purchase a wildcard SSL certificate (because I need to secure a number of subdomains), and when I first searched for where to buy one I was overwhelmed with the number of choices, ...
32
votes
9answers
15k views

How to hide a password passed as command line argument?

I'm running a software daemon that requires for certain actions to enter a passphrase to unlock some features which looks for example like that: $ darkcoind masternode start <mypassphrase> ...
23
votes
3answers
6k views

What kinds of security vulnerabilities does providing DNSSEC expose?

I was planning to sign my DNS zone with DNSSEC. My zone, the registrar and my DNS server (BIND9) all support DNSSEC. The only one who doesn't support DNSSEC is my secondary nameserver provider (namely ...
29
votes
7answers
7k views

Reasons to disable / enable SELinux

In the line of this question on StackOverflow and the completely different crowd we have here, I wonder: what are your reasons to disable SELinux (assuming most people still do)? Would you like to ...
10
votes
6answers
3k views

What should every sysadmin know before administrating a public server?

Similar to this question on Stack Overflow, what should a sysadmin who is used to private, intranet-type situations know before being the administrator of a public site? These could be security ...
29
votes
5answers
9k views

Functional implications of differences in SSL and TLS

I know that TLS is essentially a newer version of SSL, and that it generally supports transitioning a connection from unsecured to secured (commonly through a STARTTLS command). What I don't ...
18
votes
3answers
69k views

What are the IUSR and IWAM accounts for in IIS?

I'm looking for a good explanation of the IUSR and IWAM accounts used by IIS to help me better configure our hosting environment: Why are they there? What's the difference between them? Do the names ...
14
votes
6answers
4k views

How difficult is it to setup a mailserver?

I want a secure mail solution, as I am looking to move away from Google and other parties looking into my private data. How much of a PITA is it to setup my own mailserver? Should I go for an ...
16
votes
7answers
21k views

Automatically check for Security Updates on CentOS or Scientific Linux?

We have machines running RedHat-based distros such as CentOS or Scientific Linux. We want the systems to automatically notify us if there are any known vulnerabilities to the installed packages. ...
10
votes
2answers
14k views

How do I deploy an internal certificate authority?

IE7 aggressively warns about certificate failure; we have some internal sites that run over HTTPS and thus need a valid cert. We appear to have an certificate authority on the intranet that can sign ...
6
votes
3answers
3k views

Managing service passwords with Puppet

I'm setting up my Bacula configuration in Puppet. One thing I want to do is ensure that each password field is different. My current thought is to hash the hostname with a secret value that would ...
15
votes
8answers
3k views

What are main steps doing forensic analysis of linux box after it was hacked?

What are main steps doing forensic analysis of linux box after it was hacked? Lets say it is a generic linux server mail/web/database/ftp/ssh/samba. And it started sending spam, scanning other ...
14
votes
7answers
3k views

Storing rarely used single-purpose passwords

How do you handle the storage of passwords that, by nature of their usage, you can't expect administrators to memorize? Such as: Administrator/root password when everyone logs on using their own ...
9
votes
8answers
18k views

How to prevent a LOIC (DDOS) attack? [duplicate]

The program LOIC (in the news a lot the last days) causes a lot of damage. What can I do on my server to prevent this kind of attacks? Auto-block ip when receive a strange connection? Because mostly ...
30
votes
6answers
80k views

How to remove strict RSA key checking in SSH and what's the problem here?

I have a Linux server that whenever I connect it shows me the message that changed the SSH host key: $ ssh root@host1 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: ...
18
votes
9answers
1k views

User password age/complexity policy

Has anyone got any resources for determining a reasonable password policy for my users? My personal leaning is to ratchet up password complexity and allow them to change them less often as a kind of ...
18
votes
8answers
8k views

Should we disable the root user?

Should we remove the root password, disable remote login and basically require adminstrators to use sudo to perform administrative actions?
13
votes
9answers
6k views

SSH server zero-day exploit - Suggestions to protect ourselves

According to the Internet Storm Center, there seems to be a SSH zero-day exploit out there. There is some proof of concept code in here and some reference: http://secer.org/hacktools/0day-openssh-...
11
votes
3answers
928 views

Finding how a hacked server was hacked

I was just browsing through the site and found this question: My server's been hacked EMERGENCY. Basically the question says: My server has been hacked. What should I do? The best answer is ...
9
votes
4answers
7k views

How do you manage service account credentials (passwords)? [closed]

In a Windows environment how do you address the following issues with service accounts? Regular Password changes - with single service accounts used on multiple machines how do you regularly change ...
20
votes
3answers
31k views

How do I block specific IPs and IP ranges in IIS7?

I'm trying to block various IP addresses from every site that I have hosted from an server running Windows 2008 and IIS7. I've found various information about how to do this using Deny rules from "...
14
votes
7answers
5k views

Should I bother to block these rather lame attempts at hacking my server?

I'm running a LAMP stack, with no phpMyAdmin (yes) installed. While poking through my Apache server logs I noticed things like: 66.184.178.58 - - [16/Mar/2010:13:27:59 +0800] "GET / HTTP/1.1" 200 ...
8
votes
4answers
738 views

Remote Root Login

I know one of the first things you do to secure a server is disallowing remote root login. Passwords are pretty weak; what do people think of only allowing root login via ssh keys or other password-...
8
votes
2answers
3k views

iptables | Types of ICMP: which ones are (potentially) harmful?

I read that certain types¹ of ICMP packets can be harmful. Questions: Which ones and why? How should I layout an iptables ruleset to handle each type of ICMP packet? Should I rate-limit any of these ...
6
votes
3answers
1k views

Do I have to buy a second wildcard certificate for a subdomain?

We already have a wildcard certificate for *.mycompany.com. Our network has hosts that are only reachable internally. All of them belong to the internal.mycompany.com subdomain. There is a private ...
6
votes
2answers
7k views

Custom fail2ban Filter for phpMyadmin bruteforce attempts

In my quest to block excessive failed phpMyAdmin login attempts with fail2ban, I've created a script that logs said failed attempts to a file: /var/log/phpmyadmin_auth.log Custom log The format of ...
23
votes
3answers
36k views

What is muieblackcat?

I've recently installed ELMAH on a small .NET MVC site and I keep receiving error reports System.Web.HttpException: A public action method 'muieblackcat' was not found on controller... This is ...
11
votes
11answers
1k views

Site hacked, looking for security advice [duplicate]

Possible Duplicate: My server's been hacked EMERGENCY Last weekend my company's site was hacked. They did the nicest thing of doing that on a Friday evening so we only noticed the attack ...
9
votes
1answer
798 views

Is it possible to hide a malicious alias in Bash on Linux?

Is it possible to conceal the existence of a malicious alias in Bash on a Linux system and have it executed by the user without their knowledge?