Network Security - securing network infrastructure and connections

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31
votes
6answers
134k 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 ...
51
votes
6answers
20k 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 ...
33
votes
7answers
35k 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 ...
23
votes
3answers
5k 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. ...
24
votes
5answers
4k 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 ...
58
votes
2answers
49k 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). ...
3
votes
0answers
156k views

Hack into a computer through MAC and IP address [closed]

Is my computer vulnerable to someone who knows my modem's MAC address and my public IP address? What kind of vulnerabilities would this imply? Could they actually get access to my computer just with ...
1
vote
1answer
479 views

Attacking a server on port 80 while only port 22 is open on the firewall

There is a question bugging me a after reading on network security. Theoretical situation: there is a packet-filtering firewall, which only accepts tcp/ip communication with destination port 22 on a ...
19
votes
5answers
22k views

How to find out that a NIC is in promiscuous mode on a LAN?

How to find out that a NIC is in promiscuous mode on a LAN?
24
votes
6answers
24k 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 ...
29
votes
4answers
28k views

Should SSL be terminated at a load balancer?

When hosting a cluster of web application servers it’s common to have a reverse proxy (HAProxy, Nginx, F5, etc.) in between the cluster and the public internet to load balance traffic among app ...
17
votes
6answers
2k 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 ...
36
votes
9answers
42k 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 ...
120
votes
8answers
13k views

Are “man in the middle” attacks extremely rare?

In "Some thoughts on the iPhone contact list controversy and app security", cdixon blog Chris Dixon makes a statement about web security Many commentators have suggested that a primary security ...
86
votes
8answers
9k 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 ...
33
votes
7answers
52k 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 ...
14
votes
5answers
15k views

What is the best practice for placing DataBase servers in secure network topologies

I have a classic DMZ architecture: My webserver is placed in the DMZ. The webserver needs to communicate with a database server. This database server is the most critical component of my network ...
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 ...
7
votes
2answers
498 views

What features do you look for in an Enterprise Log Management solution?

This question is for IT Pros, and people who manage a company's infrastructure. Developers should see this related answer for tools geared for them. What are your requirements for such a Event Log ...
8
votes
2answers
11k views

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 ...
23
votes
5answers
35k 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 ...
8
votes
2answers
8k views

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 ...
7
votes
2answers
1k views

Any advantage to securing WiFi with a PSK, other than to keep out unauthorized

As I understand WiFi with a PSK, such as WPA(2)-PSK or WEP, anyone on the same network can decrypt anyone elses packets because everybody has the same key. In which case, if you are not going to ...
82
votes
7answers
82k 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?
26
votes
7answers
6k 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 ...
32
votes
9answers
75k 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 ...
21
votes
7answers
1k 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 ...
15
votes
2answers
5k views

Reject IP packets with an ICMP error, or just drop them?

Consider an internet-facing host (the outer firewall). What should be done with undesired traffic: just drop it, or send back an ICMP error such as port unreachable? (In Linux terms: iptables -P DROP ...
13
votes
5answers
3k views

Access to a router's GUI

During a recent visit to a coffee shop, I noticed that they hadn't bothered changing their default user name and password for their router. I realise that someone could log on and be annoying to ...
43
votes
9answers
21k 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 ...
13
votes
3answers
4k views

Nessus vs third-party scans

As part of our PCI-DSS compliance process we get scans done by a third party. Based on the form and wording of the output, it's pretty clear they're using Nessus for most of their heavy lifting. Same ...
22
votes
4answers
6k 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 ...
4
votes
4answers
15k views

What are the laws regarding ISP recording IP addresses? How would they know who had which?

Since most internet users have ISPs using dynamic IP addresses (e.g. someone gets a new external IP address every few days) are there any laws requiring the ISPs to keep logs associating an IP address ...
13
votes
1answer
5k views

SFTP, FTPS and SecureFTP differences and security implications

What are the basic differences and security implications of using SFTP, FTPS and SecureFTP.
11
votes
5answers
17k views

Can Skype chat be protected from snooping? Are there safe alternatives?

I use Skype a lot. With all of my clients, staff, contractors and friends, however, the acquisition by Microsoft worries me, as two of my clients are direct MS competitors, and I often work on long ...
16
votes
2answers
1k 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 ...
8
votes
1answer
12k views

Are open ports dangerous?

I have forwarded port 80 to WAMPServer and 25565 to the MineCraft-server running Bukkit. (http://www.bukkit.org/) Am I vulnerable to attacks. Can hackers attack me if WAMP-server is running or if it ...
8
votes
3answers
11k 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 ...
6
votes
2answers
13k views

What is best practice for separation of trusted zones from a DMZ with a single firewall?

At our organization we have a single firewall sitting between our internal zones and the public internet. Currently all of our trusted zones are defined as different vlans on a layer 3 switch plugged ...
5
votes
7answers
2k views

What security risks exist in cell phone apps' data transfer?

Smartphones apps transfer various types of data over the provider's data network (or wifi, if enabled). What security risks are there in this transfer, and how can the risks be mitigated? I'm not ...
3
votes
5answers
1k views

Can teleworking let my boss to sniff my network traffic? What else could he do?

My boss proposed me to code from home on the their machines via internet, in two possible ways: I would connect to their computer and work on their machine, as if I was in front of the computer(from ...
9
votes
2answers
642 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 ...
8
votes
4answers
654 views

CAM table attack in 2011?

Today's switches are vulnerable to CAM Table attack? https://secure.wikimedia.org/wikipedia/en/wiki/CAM_Table
5
votes
3answers
7k views

Resolving an IP address of a Remote machine to its MAC address

I wanted to know whether its possible to get the MAC address of remote node (computer/Access Point) if I know its IP address. I have heard that if someone sends you an email (even through gmail), you ...
3
votes
7answers
2k views

Scanning A Subnet Externaly

Scenario: I have a router with a public IP address provided by the ISP and two hosts behind the router with a private IP (192.168.x.x). Is it possible to perform a port or vulnerability scan of a ...
2
votes
3answers
358 views

Without SSL, what vantage point does one need to MITM non-SSL'd HTTP?

OK, so there are two things here: being able to read the content of the requests and responses, and then being able to modify them. The former may depend on the latter, I'm not sure. But basically, ...
31
votes
10answers
28k 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 ...
21
votes
12answers
39k 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 ...
14
votes
3answers
1k 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 ...
22
votes
6answers
2k 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 ...