Network Security - securing network infrastructure and connections

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109
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8answers
11k views

Are “man in the middle” attacks extremely rare?

In http://cdixon.org/2012/02/12/the-iphone-contact-list-controversy-and-app-security/ Chris Dixon makes a statement about web security Many commentators have suggested that a primary security ...
83
votes
8answers
7k views

How can I protect my internet-connected devices from discovery by Shodan?

There's been a lot of buzz around this recent CNN article about Shodan, a search engine that can find and allow access to unsecured internet-connected devices. Shodan runs 24/7 and collects ...
51
votes
5answers
46k views

What is the difference between SSL vs SSH? Which is more secure?

What is the difference between SSH and SSL? Which one is more secure, if you can compare them together? Which has more potential vulnerabilities?
43
votes
2answers
20k views

Is it a bad idea for a firewall to block ICMP?

This question was inspired by this answer which states in part: The generic firewall manifest file finishes off by dropping everything I didn't otherwise allow (besides ICMP. Don't turn off ICMP). ...
39
votes
6answers
11k views

What techniques do advanced firewalls use to protect againt DoS/DDoS?

It is hard to protect a server against Denial of Service attacks, DoS/DDoS. The two simple ways I can think of is to use a server with much resources (e.g. CPU and memory), and to build the server ...
34
votes
1answer
2k views

What's the risk if I accidently type my password into a username field (Windows logon)?

I'm used to logging into my personal Mac which is a password-only field (like waking from sleep mode). Sometimes I have to use a Windows network on which I have an account, but of course I have to ...
30
votes
9answers
20k views

Why block outgoing network traffic with a firewall?

In terms of a home network, is there any reason to set up a router firewall so that all outgoing ports are blocked, and then open specific ports for things such as HTTP, HTTPS, etc. Given that every ...
30
votes
7answers
19k views

Why do people tell me not to use VLANs for security?

I have a network, where a have a couple of VLANS. There is a firewall between the 2 VLANs. I am using HP Procurve switches and have made sure that switch-to-switch links accept tagged frames only and ...
29
votes
6answers
3k views

Can malware be dangerous even when quarantined?

I am reading a book on network security and when talking about user confusion it writes: "It is not uncommon for a user to be asked security questions such as Is it safe to quarantine this ...
29
votes
8answers
12k views

Are powerline ethernet adapters inherently secure?

I have 2 Zyxel PLA407 powerline adapters. Router is downstairs connected to one adapter, other adapter is upstairs about 30 feet away connected to a desktop. I have a house, not an apartment or ...
28
votes
3answers
11k views

How do you stop a hacker when their IP address is 0.0.0.0?

Wordfence reports the following visitor: An unknown location at IP 0.0.0.0 visited 4 hours 45 mins ago IP: 0.0.0.0 Browser: Baiduspider version 2.0 Mozilla/5.0 (compatible; Baiduspider/2.0; ...
23
votes
7answers
2k views

Is having Steam installed a security risk?

Speaking to one of our security administrators at work, he insists that Steam is a well understood security risk and it shouldn't be installed on work machines. Saying it's not work related I ...
23
votes
9answers
46k views

How secure is TeamViewer for simple remote support?

I'm deploying a web-based ERP system for a customer, such that both the server and the client machines will be inside the customer's intranet. I was advised in another question not to use TeamViewer ...
23
votes
3answers
2k views

How does Convergence (CA replacement) prevent its notaries from being MITM'd as well?

I have been looking into Convergence and how it works, but I cant figure out how it is effective against a MITM attack that happens near the target system. My understanding is that Convergence works ...
23
votes
3answers
713 views

What are the security risks in enabling ipv6

We are considering enabling ipv6 on our webservers, so that we are reachable with both ipv4 and ipv6. Are there any security issues we should consider when enabling ipv6?
22
votes
5answers
24k views

Is it still unsafe to email credit card number nowadays?

We all know not to do it, but someone emailed my credit card number and cvv code to my gmail. I'm wondering if the risk is so low I don't have to call to cancel my card. The email is sent from a ...
22
votes
3answers
3k views

How do DoS/DDoS work?

In the last days one could frequently read about attacks from anonymous and LulzSec against different platforms like Sony or HBGary etc. Yesterday for example they DDoS'ed soca.gov.uk and jhw.gov.cn. ...
21
votes
7answers
11k views

DDoS - Impossible to stop?

Is it possible - in theory - to stop1 a DDoS attack of any size? Many people claim it's impossible to stop DDoS attacks and tell me I just shouldn't mess with the wrong people on the internet. But ...
20
votes
7answers
29k views

What is the difference in security between a VPN- and a SSL-connection?

I would like to design a client-server application where the server is placed on Internet. I assume that I could set up the client-server connection using VPN (is it using IPSec?) or using a SSL ...
20
votes
1answer
104k views

Why can you bypass restricted WiFis by adding “?.jpg” to the URL?

I recently read an article on Hacking a commercial airport WLAN. It's basically about circumventing paid airport WiFi redirections (they redirect you to a certain URL when you type something in the ...
20
votes
2answers
2k views

Do simple Linux servers really need a non-root user for security reasons?

Playing devil's advocate, Let's assume I purchase a Linux server from a hosting provider. I am given a password for the root user and am told I may login using SSH. The only purpose this server has ...
20
votes
6answers
70k views

If someone hacks my wi-fi connnection, what can they see and how?

I have two questions on wifi security: If someone knows my wifi password (be it WEP or WPA) what can they see on my screen? Do they just see URLs I visit, or can they see everything in my ...
19
votes
5answers
2k views

419 Nigerian scam problem

I fell in a scamming trap. It took me a while to figure it out. Blinded like an idiot. But it is what it is. I can only do as much as I can now. Tell me if there is anything else I should do. After ...
19
votes
5answers
3k views

Security impact of using a public password for free WiFi

We have a WiFi network that we want to be public and free. Does having a password that is known to everyone provide any additional security advantage to the people using this network as opposed to ...
19
votes
2answers
41k views

What is the real function and use of a DMZ on a network?

I read the article on Wikipedia describing what a DMZ (demilitarized zone) is on a network, but am still failing to grasp both how it is set up (ie: is it within the main network or sequestered away?) ...
19
votes
1answer
4k views

What are darknets, and how can they be used to provide security and anonymity in network communication?

One of the major problems with the internet is that it's difficult to stay anonymous while retaining the ability to communicate with a large number of people. While encryption can be done effectively ...
19
votes
3answers
7k views

What benefits does Nessus have over OpenVAS?

Nessus and OpenVAS appear to have fairly similar features. Why would you choose one over the other, besides the benefit of commercial support (which isn't available for Nessus Home Feed users ...
19
votes
3answers
1k views

What are the risks of using a CDN to speed up my website? How do I avoid them?

Content Delivery Networks (CDNs) are well known to speed up the performance of a website, but they create the obvious security risks if someone were to change the code that resides on the CDN. What ...
18
votes
7answers
955 views

Securing the security guy's home office: what should we do?

I read an article in the latest InfoSecurity magazine (an infosec trade rag by Elsevier) saying that us security professionals aren't necessarily taking the correct steps to protect our own home ...
18
votes
7answers
3k views

Port Knocking is it a good idea?

Normally for a server I like to lock down SSH and other non-public service to only be accessible by certain IP addresses. However this is not always practical if the business doesn’t have static IP ...
18
votes
6answers
1k views

How to secure a WiFi network?

What do I have to do to secure a WiFi network? Is there any best practices? I have been recommended to use WPA2 encryption on the router, is that enough? What can I do to improve the security even ...
18
votes
4answers
1k views

IPsec (Internet Protocol Security) facts

Internet Protocol Security (IPsec) is a successor of the ISO standard Network Layer Security Protocol (NLSP). What are the advantages, disadvantages, other interesting facts regarding the protocol?
18
votes
3answers
3k views

Are popular porn sites more likely to be infected with malware?

I'm trying to help my friend understand this because he believes that since a site is very popular, that it's less likely to infect its viewers because of its security! Is a popular site less likely ...
17
votes
9answers
3k views

Can IP address be a component of 2-factor authentication?

I have a bunch of Linux machines that I wish to administer over the Internet. I currently use SSH keys, but have been advised to use 2-factor authentication. SSH Keys are something you know. Is an IP ...
17
votes
5answers
6k views

Do you detect/react to DNS tunnelling?

I've just seen a talk about tunnelling TCP/IP over DNS requests, because port 53 UDP is usually open and unfiltered. What techniques exist to detect and block such tunnels, and have you ever seen that ...
17
votes
5answers
10k views

Can I detect a MITM attack?

Based on this question here: Are "man in the middle" attacks extremely rare? Is it possible to detect man-in-the-middle attacks, and if so, how would one go about it? In addition, what if ...
16
votes
2answers
1k views

Hosting an “IP Rental” address. Is this common, safe?

I have a supposed opportunity to get in with an individual with advertising and a side business of his, renting IP addresses. He has asked me to set a dedicated DSL account at my house. Is there any ...
16
votes
5answers
14k views

Security risk of PING?

I have been told that PING presents a security risk, and it's a good idea to disable/block it on production web servers. Some research tells me that there are indeed security risks. Is it common ...
16
votes
12answers
25k views

Public DMZ network architecture

Years ago, when I was a student, a network security professor taught me in a class what a DMZ is. The architecture he used in his slides was similar to this one: Now that I got employed, my boss, a ...
16
votes
6answers
1k views

What security risks does IP spoofing bring?

By manipulating the TCP packet and changing the source address one is able to spoof the IP. As I understand it, you will not be able to set up a full handshake by doing this, as you will never receive ...
16
votes
5answers
2k views

To firewall or not to firewall?

There's recently been some discussion (to be generous) about the pros and cons of having a firewall deployed in front of servers. The con mainly being that it's a point of failure in case of a DDoS. ...
16
votes
2answers
736 views

In what scenarios is relying on source IP address as a security control acceptable/unacceptable?

I've noticed that there's a number of questions where relying on source IP address as a control gets mentioned and in most gets dismissed as being unreliable. I'd be interested in hearing from anyone ...
16
votes
3answers
965 views

What techniques and tools do you use to relate security events?

You have central logging going, detailed app logging/alerting (e.g. modsec), network based security alerting (e.g. snort), and whatever else feeding your observation deck. Do you have any cool ...
15
votes
3answers
3k views

Recommendations for honeypot software

A couple of us wanted to setup a honeypot/honeynet with the goal of learning; not planned to be in a production environment. What's a good recommendation for a high interaction or low interaction ...
14
votes
3answers
2k views

Bruteforce attack on my FTP server

I recently setup VSFTPD on my personal server for sharing files over FTP. In the vsftpd.log file, i see hundreds of failed attempts to login with usernames like "adminitrator" , "adminitrator1", ...
14
votes
6answers
3k views

Are some uncommon TCP ports scanned less than others?

Ignoring the top 5-10% of port numbers for common services that are the commonly targeted by port scanners (i.e. ports 22-ssh, 23-telnet, 80-http, 139-smb/cifs, 443-https, 3389-rdp, etc.), are the ...
14
votes
4answers
10k views

How are spoofed packets detected?

My assumption: When a firewall is configured to drop spoofed packets, it tries to ping (not necessarily ICMP) the source IP and sees if it belongs to a real host or if it's up, and if not, it drops ...
14
votes
5answers
17k views

DHCP vs. Static IP Addressing

How do DHCP and Static IP addressing compare, from a security standpoint? What are the risks/benefits associated with each? I know the preferred solution between the two will vary with network size ...
14
votes
3answers
520 views

What security mechanisms are used in BGP and why do they fail?

I just read about Indosat trying to take over the Internet by mistake. I read on a Polish infosec-related website that most of their announced routes failed to propagate, but some of them reach the ...
14
votes
4answers
1k views

Threat assesment for a captive portal

I am interested in setting up a captive portal on a wireless network. From what I understand I would do this by initially having all guests in a temporary vlan, moving them to the real vlan when ...