Concerned with software or hardware firewalls

learn more… | top users | synonyms (1)

4
votes
3answers
12k views

How do you properly setup Tor on Windows 7?

How do you properly setup Tor on a Windows 7 box to guarantee that ALL connections will run through Tor?
4
votes
1answer
7k views

Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I think)...
4
votes
2answers
633 views

Firewall design for big enterprise business

I am wondering if there is any best practice firewalling rules that should be put in effect in most modern networks. For example should the network atleast have the following firewall zones? Client ...
4
votes
2answers
5k views

What's the difference between an application-level and circuit-level gateway?

From Wikipedia, I understand that circuit level gateways look at TCP handshakes to filter illegitimate traffic and that application level gateways somehow filter application specific traffic. But I ...
4
votes
1answer
421 views

Exploited by newbie3viLc063s

My debian server got exploited by some scriptiekiddie who used Newbie3viLc063 http://pastebin.com/jma8JRG1 . Scriptkiddie uploaded logo_php.png to my server (My permissions sucked :s) and he did run ...
4
votes
3answers
14k views

Is it really better to use port 80 or 443 for outgoing traffic in order to bypass user firewall?

I recently created a reverse connection shell in C#. I tested it with some computers and I noticed that some computers connected back correctly and I established connection with them but another ...
4
votes
1answer
355 views

Placing a firewall—without creating a new subnetwork

I have a couple of networks that have multiple IP addresses, and where I have absolutely no choice as to the equipment used for the network's edge router (the device that connects both to the LAN and ...
4
votes
1answer
355 views

Can a Cisco ASA 5505 block this DDoS attack?

Since more than a week ago, my dedicated server (located at ovh.com) has been under TCP SYN (I think) attack. OVH don't care about it but this attack is killing my server with a high CPU load (...
4
votes
2answers
71 views

monitor port scan on the same segment

if theres a port scan on the same segment and it does not reach the firewall at all, it is not detectable by anything. is there any solution to that ? maybe using the windows fw on ach workstation to ...
4
votes
2answers
2k views

Cisco ASA Security Contexts: Any Real World Installs?

We are looking at deploying a Cisco ASA 5520-I am looking at the security contexts feature, and was wondering if anyone has deployed their ASA in this way, and how it is working out for them. Have ...
4
votes
2answers
357 views

What criteria do you use for evaluating Client-Side / Endpoint security products?

What features are important to you in client-side AV and Firewall products? Who benefits from these features? Managment, the end user, helpdesk. Are there features that are being 'sold' by the ...
4
votes
2answers
439 views

Firewall egress filtering by domain

In our production environment, we are connecting to a few core external service providers though their APIs, and are required to have all other services blocked (PCI DSS). We currently have a ...
4
votes
3answers
2k views

Effectively limiting outgoing firewall traffic to frequently-changing IPs

PCI DSS 1.2.1 states: Restrict inbound and outbound traffic to that which is necessary for the cardholder data environment. Verify that all other inbound and outbound traffic is ...
4
votes
1answer
1k 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 ...
4
votes
1answer
288 views

IPtables Linux Firewall and IPsec traffic

Can iptables filter out incoming datagrams that are IPSec-tunneled packets going to port 25?
4
votes
2answers
494 views

Long character sequence in first string of HTTP GET request breaks the web service's HTTP response. Buffer overflow?

During my current security audit test I've stumbled on something I can't possibly comprehend. The behavior exhibits signs of a buffer overflow in the target or in some intermidiate service (HTTP proxy/...
4
votes
1answer
217 views

DMZ Firewall settings

I am involved in project where I have to install a new server for a new application to a preexisting production network. The new server shall sit in the DMZ and two controllers will sit on the ...
4
votes
1answer
841 views

IP address filtering vs web application security

We have a web application behind a firewall that requires no user authentication. If we open up access to this application via the firewall to a small list of IP addresses what is the risk of ...
4
votes
1answer
79 views

Is there such thing as an OS “internal firewall”

I was wondering if there is such thing as an OS "internal firewall". If it exists, it must be under a different name. I am looking for a way to control which applications can talk to which other ...
4
votes
1answer
509 views

Benefits of home router behind Linux firewall?

Like a lot of people I have a simple consumer grade router at home. The setup is pretty standard: Ethernet from the cable modem --> router's WAN Given the poor track record of consumer routers ...
4
votes
4answers
1k views

Find out what Linux software is trying to phone home

I have seen some suspicious outbound communications blocked on my VPS, which hosts a small experimental Web site, and want to find out which application is making the attempt. The server is running ...
4
votes
3answers
11k views

Securing a network attached storage on the internet

I recently purchased a network attached storage for personal file storage and would like my family members to store files on the device from their computers as a remote backup. I'd like to secure ...
4
votes
1answer
216 views

firewall with cloud based malware analysis risks

Palo Alto, and probably others firewalls will offer it, has a feature to do malware analysis in a separate (cloud-based) process that does not impact stream processing. What I would like which risks ...
4
votes
2answers
4k views

Windows Firewall Connection Security with Certificate

I've been fiddling with the Windows firewall configuration of some computers within a VMWare based LAN (no domain). To aid in my testing and debugging, I created a small, self-hosted console ...
3
votes
2answers
2k views

How does a firewall help to protect a server?

Since a potential attacker will exploit the services that are already open to public by firewall rules, how will a firewall help to protect my server from attackers?
3
votes
4answers
440 views

What does a switched network protect us from? What does it not protect us from?

There seems to be some misconceptions regarding what a switched network will protect us from, and what technologies/precautions a secure environment requires when segmenting trusted users from hostile ...
3
votes
3answers
551 views

iptables rule to ban and redirect malicious traffic

I'm running Apache 2 and after analysing the access_log I discovered that my website is visited more than 800 times a day (today 924) from majestic.co.uk bot. The bot use this range of IP addresses: ...
3
votes
3answers
3k views

How can reverse proxies be used to bypass acceptable use policies of a company?

I am wondering how reverse proxies can be used to bypass company acceptable use policies? What can be done to prevent it?
3
votes
2answers
2k views

Reverse shell connections

Why are reverse shell connections so popular in the event of a successful intrusion? Many "hacking" videos show this and it is often seen in practice. Would not most servers restrict outgoing ...
3
votes
1answer
127 views

Why guest's connections can pass host's firewall?

I've been wondering about this. Assume a host with a strong firewall setup (for example only allowing port 80). That host has some virtual machines without firewall. Why the connections made on ...
3
votes
4answers
1k views

Security risk of allowing ICMP “destination unreachable” packets on AWS

If I configure an Amazon AWS VPC, should I explicitly allow ICMP "destination unreachable" packets inbound? I am wanting the VPC firewall to block everything by default, however does this mean this (...
3
votes
3answers
2k views

Why block network ports?

There was another good question here on why you should block outgoing traffic: Why block outgoing network traffic with a firewall? But I was hoping to get an answer on why it is a good idea to block ...
3
votes
3answers
3k views

why blocking incoming traffic does not block chatting or VOIP

I just recently blocked all incoming traffic(all local ports and all external ips) in my windows 7 firewall and I understand that will not stop me from accessing websites as browsing needs outbound ...
3
votes
2answers
7k views

If a port is closed how come you can still use it?

What does it actually mean for a port to be closed or stealthed? According to tests I've run all my ports (tested) are stealthed but clearly I can still use the internet. Also are the terms "blocked" ...
3
votes
2answers
179 views

Decrypt and then re-encrypt all requests to the internet at firewall level

I don't have strong skills about this matter but I am very curious about the following communication so may I ask: One institution sent a message to all network users saying that "all requests to the ...
3
votes
2answers
841 views

Using only a firewall, how do I protect a database server from be exposed?

If I had two firewalls, I could put a web server within a DMZ and then with the second firewall restrict the access to the DB server. However, If I only have one firewall, how could I accomplish this?...
3
votes
5answers
6k views

SYN flooding attack causing high CPU on hardware firewall

I have a ZyWall USG 200 firewall. A few days ago there was a SYN flooding attack on it causing 100% CPU load. After investigating it turns out this was attack from a single IP address and while the ...
3
votes
2answers
256 views

How to red team against firewalled architecture?

Prior Knowledge I understand the types and differences between firewalls. I have (what I believe to be) a relatively good mental model of a firewall. I understand routing, iptables, signature ...
3
votes
2answers
505 views

Blocking executables at the firewall in the enterprise

The infrastructure team in our medium enterprise has requested blocking of all executables at the firewall. We have a firewall which is capable of DLP, so therefore this can be set up fairly easily. I'...
3
votes
2answers
261 views

Is it safe to not update Windows if you dont accept any incoming connections?

I see this guy shared his thought: How to be safe even without most updated Windows updates So he claims that as long as you do not accept any incoming connections and just use sandbox of Chrome, ...
3
votes
2answers
130 views

Reverse Proxy or direct?

imagine I have an architecture as shown. In order to get to the internal web server, should I use a reverse proxy like as shown and redirect traffic to my web server? Is this a more secure way ...
3
votes
2answers
431 views

Firewall egress filtering / quick whitelisting

Suppose your Aunt or Uncle is easily fooled by phishing attempts and their computer has multiple root kits and key loggers running. Assume their computing habits will never change. Looking at his ...
3
votes
2answers
4k views

Benefits of REJECT over DROP on a single PC

Recently I learned about the difference between DROP and REJECT in a firewall. I understand that REJECT is better because it closes the connection immediately instead of waiting for timeout as DROP ...
3
votes
3answers
474 views

Are local firewalls necessary

Is having local firewalls enabled on machines actually necessary if you run hardware based firewalls like pfsense or a netgear fvs338 and use that to control in/out bound connections? I personally do ...
3
votes
2answers
1k views

Reviewing IP(s) that has been blocked by firewall / router

Is there a best practice on how to review IP(s) that are blocked on firewall / router and determine if they are safe to be removed from banned list? Occasionally, the firewall guys see a high counts ...
3
votes
2answers
10k views

Disabling windows firewall remotely

i use metasploit for pentesting windows 2003 sp2 server but when windows firewall is on i am not able to perform pentest successfully is there any way to disable firewall remotly?
3
votes
1answer
70 views

Blocking all incoming traffic, will it still accept a response from a request I initiated?

I am a 'newbie' when it comes to firewalls, but I am trying to launch some machines that will connect to Facebook's Graphs API. I only want these machines to contact Facebook and nothing else. By this ...
3
votes
1answer
823 views

How can the Google web crawler bypass portals?

This is a situation that I have encountered on a number of occasions. I will conduct a web search in Google, a link to a file (.pdf for example) will take you to that file on the server. It opens up ...
3
votes
1answer
2k views

Incoming Packet From Source Port 80

I'm sure no daemon or browser is using network resources, but I found incoming packets from Wireshark: 98.126.43.174 source port 80 --TCP--> MyIp destination port 339 [SYN, ACK] 98.126.43.174 ...
3
votes
2answers
3k views

How secure is opening an incoming port for a java application?

If a java application is listening on UDP port xxxxx and a firewall is allowing connections to that java application through the same UDP port xxxxx, what vulnerabilities will a Windows 7 machine be ...