Network Security - securing network infrastructure and connections

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How can someone hack my PC if I am connecting to the internet through NAT?

If I own a private IP address, 192.168.2.1 for the sake of it, and I am physically connected to my router, which it's internal interface is 192.168.2.254 and it's external interface is some public IP ...
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1answer
2k views

AWS VPC - should connections between instances be over SSL?

Say I have a few EC2 instances in an AWS VPC network, each assigned its own private address for the subnet at creation. Say one of them is a DB, and another one some kind of web app talking to the DB. ...
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2answers
3k views

Bypassing a reverse proxy/NAT

Reverse proxies and NAT would seem to obscure a network behind such technologies to the point where it would be hard if not impossible to identify ports open and services running. Given that many ...
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3answers
581 views

Tools needed to setup a paranoid remote backup server

I'm a system admin with little security experience. I want to schedule the copying of our backups to protect our data in case of fire. The best solution would be to copy the data onto a new ...
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2answers
756 views

What is a “pre-play” attack?

I understand what a replay attack is, but I keep reading about a pre-play attack. What is it? Is it when someone intercepts an unused message and blocks the sender so they can't finish using it, and ...
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1answer
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ports blocked by firewall and not the server

I was asked this question at an interview and i wasn't sure about the answer. The question was "suppose you were checking the open ports on a particular webserver which was behind a firewall, how ...
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2answers
2k views

Malware known to use port knocking to evade detection by network scanners?

Are there any known cases of malware in the wild that utilize port knocking on a backdoor to evade detection by network scanners?
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2answers
1k views

Online SQL Server database for a Business app. Security considerations

A business application works with a SQL Server database. A SQL Server 2008 is installed on one of the computers of the local network. Technically this app works OK if the server computer with the SQL ...
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3answers
13k views

How to best set up public WiFi without giving access to the rest of my network?

For reference, this is just for my home network. Anyway, I have quite a few of my neighbors ask me to share my internet with them. I'd really like to eliminate this "here's the password" portion ...
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4answers
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extract from pcap all protocols found

I have some pcap files, and i would like just to get a list of protocols that are present on that pcap file. I would like it in a batch mode, not using wireshark I think tshark is able to do it, but ...
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8answers
820 views

Battling Malware without spending money

Our environment consists of about 80 users running Windows 7. Previous to me showing up as a full time IT employee, the company had contracted an outsource IT solution. As part of their set up, they ...
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3answers
653 views

Is secure Caller ID possible for SIP / VOIP?

Is there any way (standard, proposed or draft) that will allow for secure Caller ID over SIP / VOIP networks? I have constantly heard that Caller ID is insecure when used over these services. Can ...
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4answers
375 views

What are the main security considerations that must be taken into account if you intend on creating a (localised) whistleblower website?

Also: Is it something that can be achieved with limited funds? I ask because I am intrigued by the obstacles that are in place.
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6answers
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How to detect eavesdropping by your ISP

I've noticed some funny behavior lately with my home Internet connection such as connections dropping frequently, rate limiting occuring, and packet loss. I know how to get around this online, use a ...
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2answers
13k views

Recommended Cipher Suites for TLS 1.0, 1.1 and 1.2

There are a lot of cipher suites defined in the in the specifications itself of TLS 1.0, 1.1 and 1.2. And furthermore, there exist RFCs which add even more cipher suites to a specific version (e.g. ...
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3answers
7k views

Security measures for a WiFi access point?

I am planning to purchase a program that comes with an App that allows you to control the program via phone. The developer told me that the connection will be done via an extra WIFI box connecting to ...
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3answers
957 views

Can an attacker “simulate” a private IP address?

I have a SSH server with a rule that does not allow password connections outside the local network. So people already on the local network, either physically or via VPN, are allowed to connect with ...
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4answers
260 views

How to design a home network for IoT devices?

I'm trying to work out how best to design a home network which contains (potentially hostile) devices. I'm running into my limits of networking knowledge! I have two challenges. Unsecure Devices ...
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2answers
20k views

Is NAT Loopback on my router a security problem?

Some DSL routers prevent NAT loopback. Security is sometimes cited as the reason. Is NAT loopback really a security issue? And if so, how is this exploited? NAT loopback... where a machine on the LAN ...
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9answers
600 views

Which factors should you take into account when deciding whether users should be informed of a penetration test?

Say you are conducting a penetration test of an internal network. The internal network comprises of workstations, servers and company and contractor laptops. In an ideal world, the penetration test ...
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4answers
1k views

How to determine if a VPN provider respects data confidentiality?

I've read about why I really should use a VPN and I've been looking into different providers, but there's one thing I'm worried about. Can't a VPN provider just look at my traffic all they want and ...
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1answer
956 views

Checksums do not match when I download file over http

Just for the test I did the following: Downloaded a page from wikipedia via wget on remote server and named the file test.dat. Then I executed md5sum. I download the file via http and check it back ...
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1answer
207 views

Long running SMTP session

I recently noticed an SMTP session on my server which started when a remote host connected but never seemed to result in any emails being delivered. I could see that it was probably a SPAM site and so ...
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3answers
889 views

How did the spammers get this address?

A few months ago I configured a test mail server on Amazon AWS, all legit. I used a new address to my catchall-domain (something similar to, but not exactly, ...
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2answers
576 views

How do you Secure VOIP in a large organization

As part of a large organization looking to implement VoIP, to get on the bandwagon of savings and converged network focus, I'm being asked to look at the security concerns to develop a policy to help ...
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2answers
703 views

How to implement secure device identification in a for-pay wifi router to prevent usage fraud?

After reading this question about how for-pay wifi routers identify specific devices it got me thinking about what a secure alternative might be. I know that certain research has focused on ...
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3answers
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Secure PXE network OS installation

How can one make sure that when PXE is being used to boot a remote operating system, that the data being sent is encrypted (or at the very least that integrity is maintained)? Would it be possible to ...
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1answer
5k views

Obtain credentials by spoofing WPA/WPA2 Enterprise network?

I have a large scale wireless network secured using WPA/WPA2 Enterprise authentication. Recently, I was made aware of the possibility that someone may use a dd-wrt router and a computer to spoof the ...
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4answers
1k views

A firewall without any extra features [closed]

I have Kaspersky Internet Security (KIS) installed on my system. I always keep it disabled, yet using a few practices, I kept my system virus free for years: I disabled autorun using these tricks; I ...
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6answers
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Dual Router Configuration

I have a home network that was hacked into recently. The people that got into my network actually accessed my personal files and although I cannot prove it, I think they might have stolen some of ...
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3answers
14k views

How can I keep a roommate from seeing my web activity?

I have a roommate who is a network security engineer and I think he hacked our home network and now knows what sites I am visiting and what I am doing online. Although he is not stealing anything I ...
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8answers
30k views

How to block some websites and torrent usage in a small office?

In my office there are approaximately 25 systems are connected through network and all having internet accessibility.but some people are missusing this facilities like downloading films from torrent ...
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5answers
7k views

What kind of attacks against home router's NAT do exist?

I always thought NAT was some kind of a security feature and I still think it is, because if it didn't existed the internet, respectively the clients behind NATs, would be even more insecure, since ...
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685 views

networking and security

I'm trying to pick up networking security within a reasonable amount of time. I'm not specifically looking to learn about all the little tools that are available (although I do want to know about ...
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1answer
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Does restricting the names of computers allowed to connect to a wifi network provide any security

In response to a statement elsewhere that MAC address filtering was essentially useless for protecting a wifi network because it was trivially by passable by network attack tools, I was asked if the ...
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4answers
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Is the US military secret network SIPRNet physically or cryptographicaly separated/secured?

I've read the Wikipedia articles on SIPRNet and NIPRNet (which are pretty light on details) and they are supposed to be considered separate. At the network level, are they technologically ...
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5answers
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What Man-made Physical Threat Could Pose Severe Danger to a Server Farm?

I am writing a novel in which a researcher attempts to work against a study he is a part of by purposely sabotaging operations on the research compound. I am wondering if the following is plausible. ...
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2answers
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Using RSA with 3DES instead of plain 3DES. Does it make sense?

I have a large legacy code. Currently it is using 3DES encryption for a network based application. It encrypts data packets with a main key. This key is used to encrypt and decrypt (symmetrical). And ...
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2answers
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How to be safe from wifikill!

I recently found that my friend is using wifikill apk on his rooted android and I would like to get rid of that software as I always get kicked from my wifi. I have to give him the password of my wifi ...
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2answers
360 views

What is secure enough for web applications?

we intend to build a network in a small health center with No Internet Access it is expected to have 30 terminal machines, all machines will use an electronic medical record web application we want ...
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4answers
9k views

How to detect hosts running in virtual machines with nmap?

I have to determine if a given subnet has virtual hosts. Are there any ideas about what switches to use?
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4answers
817 views

IP Address spoofing?

According to: https://secure.wikimedia.org/wikipedia/en/wiki/IP_address_spoofing "this technique is mainly used when the attacker does not care about the response or the attacker has some way of ...
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2answers
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sniffing/recording GSM 3G signals

Is it possible to sniff or record and process GSM 3G signals (from some reciever) given that there is no other signals interrupting etc (the most comfortable conditions) Update (with some supporting ...
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3answers
4k views

Encryption on mobile phone - myth?

Well, about six months ago I had pleasure to meet Harald Welte and when he talked about m-banking (banking via smartphones) he said that the most people thing it's safe while, in fact, mobile ...
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4answers
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How can a company reduce exposure to packet spoofing? What solution should exist, but doesn't?

I'd like to understand what anti-packet-spoofing technology exists (or should exist) to verify an inbound packet. Maybe this is as simple as a Cisco ACL, Firewall Rule, implemented at the network ...
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3answers
5k views

Advantages of separating Web server from Database

What are the security advantages of installing the database of a web application on a server other than the one containing the web server?
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2answers
684 views

What does a Firewall mean by “connect to TCP port without your permission”?

McAfee is reporting incoming network connections blocked from IPs like 198.252.206.149 (StackExchange Inc.), 54.179.231.116 (Amazon Technologies Inc.), 74.125.68.106 (Google Inc.), etc. The ports ...
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1answer
1k views

Is it possible to recognise and prevent MitM attacks on devices which use self-signed SSL certs?

I use both Linux and Windows at work on a large enterprise LAN. The majority of the network configuration is out of my reach. Certain SaaS applications that are hosted locally on the enterprise LAN, ...
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6k views

Block all BotNets and TOR addresses from accessing our site

I've heard that many DOS attacks and general "black hat hacking" attempts occur over the TOR network. Is it possible for me to dynamically block source IP's by their presence in a BotNet or similar ...
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3answers
869 views

Is IPv6 with NAT less secure than IPv4?

This is a follow up to a snippet from another answer. There, user Ninefingers writes: (...) only allow outbound connections, ever. Do this in spite of NAT as IPv6 will make those NAT defences ...