OpenSnitch alternatives

Douane is an application firewall that blocks unknown or unwanted traffic. It provides a more fine-grained filtering as it looks at the combination of application and used network ports. This is useful when allowing common browse traffic on port 80 and 443. Instead of all applications being able to use this port, only the ones that are granted access will be able to do so. When a new connection is not trusted yet, Douane will ask to allow or deny the traffic stream.

LPFW is the abbreviation for LeoPard FloWer and is an application firewall for Linux.

ArpOn protects a system by running as a daemon and guard against a Man in the Middle (MitM) attack due to ARP spoofing, cache poisoning, or an ARP poison routing attack.

The tool works by using three types of inspection to detect a related attack.

• SARPI (Static ARP Inspection), statically configured networks (without DHCP)
• DARPI (Dynamic ARP Inspection), dynamically configured networks (with DHCP)
• HARPI (Hybrid ARP Inspection), statically and dynamically configured networks (with DHCP)

This tool is typically used by developers and system administrators to protect their database against common database attacks. One of them is the SQL injection attack, that tries to bypass checks, resulting in data leakage. By using this tool, another level of security defense is implemented.

Typically this type of tool would be used as an additional defense layer to prevent injection attacks from reaching the database.

Portspoof is a small utility with the goal to make port scanning by other much harder. It achieves this by showing all configured TCP ports to be in the 'open' state instead of closed or filter. The related ports are also emulating valid services. This way a port scan on the system will reveal many open ports and look to have legitimate services running.

This tool may be used by developers that work with the Django framework. It adds a security layer on top of the application by looking at login attempts and track them.

0trace is a reconnaissance tool to perform so-called hop enumeration within an established TCP connection. The goal is to allow traceroute-like functionality, yet in an alternative way. It can be used to bypass firewall rules. Tools like 0trace are typically used during pentesting assignments.

360-FAAR is a tool written in Perl to parse policies and logs from firewalls. It can compare firewall policies and translate between a policy and log data. Supported firewalls include Checkpoint FW1, Cisco ASA, and Netscreen ScreenOS.

A tool like Assimilator can be of great help to 'normalize' all firewall rules into one place. Especially when a company uses different firewalls, each with their own syntax and specifics. Assimilator will then simplify the way firewall rules are created and managed.

Chiron is a security assessment framework for IPv6. It provides several modules including an IPv6 scanner, IPv6 Local Link, IPv4-to-IPv6 proxy, IPv6 attack module, and IPv6 proxy. These modules help to perform an assessment, like a penetration test.

The tool uses IPv6 extension headers to create a headers chain. This may allow evading security devices like IDS, IPS, and firewalls. Due to the flexibility of the framework, the tool can also be used to perform fuzzing of the IPv6 stack of a device.

Knock implements the principle of port knocking. It does so by using libpcap to sniff network traffic on interfaces and then use that to see if it matches a predefined sequence of steps.

nftables is supposed to replace netfilter as the primary interface of network filtering. It is available since Linux kernel 3.13. Both netfilter and nftables have been co-authored by Patrick McHardy.

Tools like opensvp can be used to test the strength of a configuration from the outside. It makes it a good tool for penetration testing and security assessments. While people may feel safe to have a firewall in place, it might be unknowingly vulnerable to several attacks on protocol level. This tool helps with finding these weaknesses.