Concerned with software or hardware firewalls

learn more… | top users | synonyms (1)

4
votes
1answer
194 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
780 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
76 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
354 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
10k 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
213 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
1k 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
4answers
28k views

How can attackers bypass firewalls? [closed]

I have read the Wikipedia article on firewalls but don't understand firewall security and how an attacker from the outside can bypass the firewall to hack target system. We all know it happens but ...
3
votes
3answers
394 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
2answers
1k 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
3answers
4k views

is it worth to implement a firewall on a web server you control?

I see the main reasons for a firewall on a web server to be defense in depth and extra cushion for a possible admin error of running an unnecessary daemon. I'm trying to see if I am overlooking ...
3
votes
4answers
412 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
2k 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
3answers
214 views

Can firewalls get affected by the traffic they process

Does such attack exist? Forgive my wild imagination but is it possible for a hacker to pretend/try to communicate with a service on the server and when the firewall examines the traffic it get's ...
3
votes
1answer
124 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
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
2answers
6k 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
155 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
751 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 ...
3
votes
5answers
5k 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
239 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
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
370 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. ...
3
votes
2answers
72 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
330 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
3answers
440 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
664 views

Configure Linux to allow network activity based on binary?

On Windows, rules can be added to the firewall to allow/deny network traffic based on which binary is sending/receiving the data. Can this be done on a Linux box, and if not, why not? Is it a bad ...
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
54 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
2answers
315 views

Why does a nmap scan give different results depending on whether it's run from inside or outside a LAN

I am testing/setting up a Thompson TG585v7 router/firewall. Results when running nmap from a computer INSIDE the LAN $ sudo nmap -O 210.86.xxx.xxx Starting Nmap 6.40 ( http://nmap.org ) at ...
3
votes
1answer
284 views

Blacklisting during a penetration test?

So i had a debate recently where one of my colleagues believed that by launching a penetration test (one requested by our clients) from our one of our IP's we could potentially get that IP/all IP's in ...
3
votes
2answers
2k 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 ...
3
votes
1answer
1k views

I'm using a Cisco ASA as a VPN endpoint. Where do the VPN clients get firewalled?

(Is this too application specific? It seems like a reasonable question that would be useful to other people...) So, I've got this ASA in front of a network that I didn't set up. It's been ...
3
votes
1answer
139 views

Who watches the watchmen? User empowerment over firewall behaviour on a personal computer

I've been exploring the gamut of free Windows firewall applications recently and have encountered the following problem: The better firewalls are excellent at stopping other apps from phoning home ...
3
votes
3answers
386 views

Security issues in a Dotnet Web application

I was required to fix three low risk security issues of a Web Application on a Windows 2003 server, NetFramework 2.0, IIS/6.0. It is tracert-able. That may assist for crackers to know network ...
3
votes
2answers
306 views

Can ipopts be used to circumvent a pf or iptables firewall source IP based blocking?

Can one use ipopts, and in particular IP source routing, to circumvent source-based blocking in pf or iptables? For example, with OpenBSD's pf: block in all # default deny block out all pass in on ...
3
votes
1answer
145 views

Are Keystroke and Click Loggers Legal? [closed]

I worked with the firewall "Nobero" which is paid and bit expensive. It is a complete Network Firewall including groups policy, banning URLs and social sites. But It has a feature of tracking users' ...
3
votes
1answer
112 views

IPsec: Is AH in tunnel mode secure?

I have a site-to-site IPsec VPN which was performing poorly (10 -20% upload/download speeds as a percentage of available WAN circuit bandwidth) when using ESP in tunnel mode with DES encryption and ...
3
votes
1answer
143 views

Tracking down the source of email attacks

For the past week our company's IDS has been blocking 100-200 meeting invite emails per day from a specific client that are loaded with buffer overflows targeted at Exchange 2003. The payloads are ...
3
votes
1answer
712 views

Limit BitTorrent Sync connections to a specific network

Is it possible to limit BitTorrent Sync connections to a a specific network using the client software? Right now the closest I can come up with would be IP limitations imposed on each client using a ...
3
votes
3answers
9k views

Config Server Firewall: What Outgoing ports need to be open for wget and apt-get install?

I am just configuring CSF and I have to specify my outbound ports here. I am trying to close as many as possible leaving only what I need open, however what do I need to leave open for wget? # Allow ...
3
votes
1answer
2k views

How can I find the process that is trying to use smtp to send email?

Previously I asked Who (which process) is calling curl? and I got very good answers (this answer in particular) which basically replace the curl binary with a shell script that logs each call to curl ...
3
votes
1answer
4k views

Is opening both TCP/UDP less secured than just TCP or UDP when needed and why?

If application needs opened port X UDP, or X TCP combination. Is there any potential risk by opening both UDP/TCP as I usually am not sure which one the application uses?
3
votes
2answers
43 views

Firewall UDP Packet Source Port 53 Ruleset Bypass

I have a question regarding recent PCI DSS scan performed on our network. On some of the Windows 2008 servers (physical and VM), there is a risk found "Firewall UDP Packet Source Port 53 Ruleset ...
3
votes
1answer
37 views

Firewall - Allow WMI internal network

I am not totally sure if this is the correct stackexchange to place this question, so just let me know if it should be somewhere else. I am looking into IT asset management systems and for these ...
3
votes
1answer
318 views

Is it possible to force client use TCP instead UDP for DNS queries?

Assume I am managing a firewall between DNS server and clients. Is there any way to force clients use TCP rather than UDP, so we can prevent DNS spoof types of DDoS attacks?
3
votes
1answer
147 views

Security of OpenVPN against sophisticated DPI solution

I'm planing to build a device (prototype) that act as a portable security gateway. To make this, I choosed OpenWRT running on Raspberry Pi with OpenVPN for VPN connection. My main purpose of this ...