Network Security - securing network infrastructure and connections

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20
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6answers
66k 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 ...
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 ...
30
votes
7answers
18k 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 ...
19
votes
5answers
2k 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 ...
42
votes
2answers
19k 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). ...
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 ...
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. ...
109
votes
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 ...
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 ...
20
votes
7answers
28k 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 ...
16
votes
5answers
13k 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 ...
30
votes
9answers
19k 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 ...
7
votes
2answers
8k 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 ...
7
votes
2answers
747 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 ...
48
votes
5answers
45k 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?
18
votes
7answers
946 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 ...
13
votes
5answers
2k 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 ...
12
votes
3answers
11k 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 ...
12
votes
2answers
3k 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
3answers
3k 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 ...
6
votes
2answers
387 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 ...
16
votes
2answers
707 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 ...
11
votes
1answer
4k views

SFTP, FTPS and SecureFTP differences and security implications

What are the basic differences and security implications of using SFTP, FTPS and SecureFTP.
4
votes
4answers
8k 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 ...
6
votes
2answers
8k 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 ...
5
votes
3answers
7k 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 ...
8
votes
2answers
468 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 ...
6
votes
2answers
5k 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 ...
2
votes
3answers
300 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, ...
83
votes
8answers
6k 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 ...
14
votes
3answers
512 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 ...
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 ...
16
votes
12answers
24k 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
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. ...
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 ...
29
votes
8answers
11k 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 ...
9
votes
5answers
2k views

Can voice chat be spied?

I wonder if voice chat (via public services like yahoo, google talk, skype, etc) is practically secure? Is it possible for the ISP or any middle point? I do not consider hacking the computers, but ...
22
votes
5answers
23k 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 ...
9
votes
6answers
6k views

Automated tools for Cisco IOS config auditing?

Are there any automated tools for auditing config files exported from Cisco IOS devices? Free/Open Source is always nice, but anything that does the job would be of interest.
6
votes
2answers
6k views

Is it possible to use the aircrack-ng tool to crack a WPA2 Enterprise network?

is this tool (aircrack-ng) capable of cracking into a WPA/WPA2 Enterprise network? This tool has major success cracking the passwords of WEP/WPA networks. If it can, how, but if not, is there another ...
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 ...
8
votes
5answers
5k views

Can I block based on Mac Address?

Incase of dynamic IP's the hacker can work around by taking a new IP or use a Proxy, is it possible to make a ban based on Mac Address ? I want to block at the Webserver level so that unwanted users ...
6
votes
2answers
5k views

Is it possible to speed up WPA/WPA2-PSK cracking using a rogue AP?

We know that WPA/WPA2-PSK uses a PTK (Pairwise Transient Key) for each client to encrypt the communication. This PTK is generated through the process known as 4-way handshake. As told in the related ...
4
votes
1answer
520 views

What are the vulnerabilities of VOIP-specific security protocols?

Existing relevant questions: How do you Secure VOIP in a large organization What are the main issues and best practice security controls when exposing SIP and H.323 to the Internet? Do secure phone ...
9
votes
2answers
2k views

Is IP spoofing relevant to TCP? Is it relevant for TLS or SSH?

I have read the TCP Connection Establishment on Wikipedia In brief the packets to start are SYN, with a (hopefully) random sequence number A from the client. SYN-ACK, responding, with A+1 and ...
7
votes
3answers
532 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 ...
7
votes
4answers
1k views

Why don't ISPs filter on source address to prevent spoofing?

I'm under the impression that if all the ISP's were required to filter on the source IP address of all outbound packets, that spoofing would be reduced considerably. Are any ISPs implementing this ...
6
votes
1answer
712 views

How to get hold of and use WPA session keys?

I'm testing sniffing and decrypting my WPA2 wifi network traffic. But when using airdecap to decrypt the capture file (created by airodump) using my WPA passphrase I only get broadcast traffic. If I ...