Kategoriarkiv: Old Base

Simple IPTABLE firewall

Protect your network with Linux’s powerful firewalling features. Linux has long had the capability for filtering packets, and it has come a long way since the early days in terms of both power and flexibility. The first generation of packet-filtering … Læs resten

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Statiske mac tabeller

Use static ARP table entries to combat spoofing and other nefarious activities. As discussed in [Hack #31], a lot of bad things can happen if someone successfully poisons the ARP table of a machine on your network. The previous hack … Læs resten

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Using ARPWATCH

Find out if there’s a “man in the middle” impersonating your server. One of the biggest threats to a computer network is a rogue system pretending to be a trusted host. Once someone has successfully impersonated another host, they can … Læs resten

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Enforce user and groups resource limits

Make sure resource-hungry users don’t bring down your entire system. Whether it’s through malicious intent or an unintentional slip, having a user bring your system down to a slow crawl by using too much memory or CPU time is no … Læs resten

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Restricted Shell Environments

Keep your users from shooting themselves (and you) in the foot. Sometimes a sandboxed environment [Hack #10] is overkill for your needs. If you want to set up a restricted environment for a group of users that only allows them … Læs resten

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Control login access with pam

Seize fine-grained control of when and where your users can access your system. In traditional Unix authentication there is not much granularity available in limiting a user’s ability to log in. For example, how would you limit the hosts that … Læs resten

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Automated systrace policy creation

Let Systrace’s automated mode do your work for you. In a true paranoid’s ideal world, system administrators would read the source code for every application on their system and be able to build system-call access policies by hand, relying only … Læs resten

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Restricting system calls with systrace (BSD)

Keep your programs from performing tasks they weren’t meant to do. One of the more exciting new features in NetBSD and OpenBSD is systrace, a system call access manager. With systrace, a system administrator can specify which programs can make … Læs resten

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Restrict apps with grsecurity

To restrict specific applications, you will need to make use of the gradm utility, which can be downloaded from the main grsecurity site (http://www.grsecurity.net). You can compile and install it in the usual way: unpack the source distribution, change into … Læs resten

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Lock down your kernel with grsecurity

Harden your system against attacks with the grsecurity kernel patch. Hardening a Unix system can be a difficult process. It typically involves setting up all the services that the system will run in the most secure fashion possible, as well … Læs resten

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