Hot answers tagged wifi
52
Unprotected Wifi networks, particularly in public places, are most certainly a threat. This is because you are connecting to a network without knowing who else could be on the network.
'Free Wifi' provided by cafes, restaurants, etc serve as excellent places for harvesting passwords.
The attacker will perform a Man in the Middle attack, typically by ...
43
Something left unsaid, Why is the user wanting a WiFi? As long as the user feels they have a legitimate need they will continue to find workarounds to any of your attempts at blocking it.
Discuss with the users what they are trying to accomplish. Perhaps create an official wifi network ( use all the security methods you wish - it will be 'yours' ). Or, ...
32
You can't allow customers to be on the same network as your own computers.
A lot of new WiFi access-points take care of this for you, by creating two wifi networks, where the "guest" network does not have access to internal computers. The Cisco/Linksys 4200 is what I have at home for guests, and it's easy to setup, but there are many other systems that have ...
28
The schemes you mention are protocols for securing 802.11x traffic over wireless networks. They don't mandate how the AP password is encrypted or hashed during storage. However, the security of the protocol does rely on making the key secure.
WEP relies on a broken RC4 implementation and has severe flaws in various aspects of its protocol which make ...
27
Most probably the blocker is designed to let images through, maybe because they are hotlinking some images on the page where they ask for you to login.
Appending ?.jpg to the URL makes the blocker think that the URL is an image. On the other hand, anything after the ? doesn't change the actual webpage requested, it only changes the GET headers. (so ...
21
After some discussion with @epeleg in chat, I think I may have a more thorough and (hopefully) clear answer.
TL;DR: The protection afforded to a Wi-Fi network by encryption with a PSK is directly proportional to the complexity of the PSK, and the effort taken to safeguard that PSK. For any environment, this requires striking a careful balance between ...
20
HTTPS is secure over public hotspots. Only a public key and encrypted messages are transmitted (and these too are signed by root certificates) during the setup of TLS, the security layer used by HTTPS. The client uses the public key to encrypt a master secret, which the server then decrypts with its private key. All data is encrypted with a function that ...
18
An attacker can always determine the client's MAC address if they can sniff packets to or from the client. This is true regardless of whether encryption is used or not. The MAC address is in the outer encapsulation layer of the 802.11 packet, and there is no encryption applied to that level. Here's a good link at Microsoft that lays out the packet ...
17
Is it safe for a small business to let customers use their wifi while waiting?
No. Even if no customer intentionally attacks his WiFi network they could be carrying some type of malware on their laptop/smart phone/portable device that might spread. Additionally the WiFi signal doesn't end at the front door. You have probably connected to a WiFi some ...
15
Letting guest coming on your network is not a good idea. But this has already been said.
A major point that must must remarked is that even for guest you need identification and authentication. In fact (I am not aware of you laws) you want to make sure to be able to track back any user of your WiFi in case of a problem with justice. If someone comes to tell ...
14
WPA2 is NOT protected against ARP poisoning.
When you perform ARP poisoning, you announce that your MAC address is responsible for a given IP address. All of this happens at a layer higher than WPA2 is aware of. Let's say layer 3. Because the WPA2 encryption link is down on layer 2, and packets destined for the attacked IP are now addressed to the ...
14
Regardless of what you do at the AP, I believe I can say with a fair amount of certainty that you will at some point find that your wireless data is being broadcast "outside the walls".
First, you must understand that your AP is not the only wireless transmitter on your home network. All of your wireless clients that connect to the AP are also ...
14
I do not know if your question is about dictionary attacks in general, or dictionary attacks in the case of a WiFi network with password protection.
For the general question of dictionary attacks: there are two kinds of dictionary attacks, the online attacks and the offline attacks. An offline attack is one such that the attacker got enough data to "test" ...
14
Firewalls can't tell where your traffic is coming from in terms of the physical network - they only see the data that the protocol provides, such as MAC / IP, which aren't much use in this case.
I think you're falling into the trap of looking for a technical solution to a managerial problem. Remember Immutable Law of Security #10: Technology is not a ...
13
They're stumbling blocks, but not insurmountable. SSID hiding can provide some protection from people looking for any SSID they can get their hands on, and MAC filtering can keep casual riffraff out. As the only methods of protecting a WLAN they're pretty weak.
For someone who wants your network specifically encryption (most especially un-broken encryption) ...
13
The other answers are correct, however there is one big fish being mostly ignored:
DNS cache poisoning
As @Larry said, since you own the router you own the DNS. Meaning you can cause any other user of that network, use any server you want for any address they request.
But more than that:
You can make leave your DNS ownership in place, even ...
13
Was prompted by conversation with @Iszi on chat to make things much clearer - to just highlight the main increased risks.
An attacker could reroute every request sent by users of the network leading to:
Phishing attack - for example the normal guidance for users is to never click on untrusted links for things like online banking, but to always type in the ...
12
Yes and no. They may not have your password in plaintext, but they have enough to potentially guess it and verify that guess (i.e. offline brute forcing).
WPA2 authentication is performed through a four-way handshake. Instead of just sending your password in plaintext to any access point you connect to, this handshake ensures that unless both parties ...
12
There is no firewall rule which can help you there: by construction, the rogue AP provides a network path which bypasses your firewalls. As long as the users have physical access to the machines they use and their USB ports (that's hard to avoid, unless you pour glue in all the USB ports...) and that the installed operating systems allow it (then again, hard ...
12
Yes, a VPN connection encrypts the connection between your computer and the remote VPN host. The connection would just look like gibberish to anyone sniffing the traffic, either in the coffee shop or on the Internet. It is worth noting that the same applies to any content sent over HTTPS even if you aren't using a VPN.
It is also worth noting that if you ...
12
The question (to most people) is an oxymoron. By definition, people will think that "open WiFi" means "un-encrypted WiFi. To me you seem to be asking "Why did the people that wrote the 802.11 standard way back in 1997 make the decisions that they did?"
The short answer - we can only find out by asking them (or seeing if there are any discussion documents ...
11
If I'm using websites that do not use HTTPS, but I'm on a WEP-protected Wi-Fi network, are my cookies safe from being sniffed by third-parties?
No. Outsiders can crack WEP networks almost as if they weren't encrypted at all, these days. Insiders have even more ease of access. Even on WPA/WPA2 networks, there are still exploits that enable insiders to ...
11
Anyone who witnesses the association process of a new client can eavesdrop on their connection.
As reassociations can be forced by a rogue host that sends a forged disassociation packet in the name of the target, it is practically always possible to listen in on all connections on a WPA(2) network with a preshared key.
You can even try it for yourself in ...
11
You will need a wireless nic that permits a 'monitor' mode, and that requires some special drivers and special nics.
Kismet's list of cards for Linux
tests on different cards
pineapple device (special device)
airpcap nic (specialized nic for Windows)
Once you get a card, you will need software to deal with the data and Kismet is the leader in this area ...
11
In addition to the answers around the policy side of things there's a couple of technical approaches that can help you here, depending on how tightly controlled your IT environment is.
USB port lockdown - in your particular case the user has made use of a USB Wi-Fi stick to create the AP. If you have software which can lock-down what classes of USB device ...
11
If your bank Web site uses HTTPS, and you dutifully check that the server name in the URL is indeed the expected name, and you don't disregard warnings about unverified or expired certificates, then yes, it is safe.
If these conditions are not met, then no, it is not safe -- but it would not be safe from anywhere else either. Public WiFi is not special in ...
10
I take it when you say WPA2 you mean WPA2-Personal. It is good enough in most cases at the moment as long as its combined with a really good password. https://www.grc.com/passwords.htm is a good generator for them.
Cloak your SSID. It won't stop a determined attacker but will stop some of the script kiddie like attackers.
Only allowing specific MAC ...
10
Speaking generally
MAC's are easily spoofed.
WEP is cracked in minutes.
WPA/WPA2 implementations are not secure in all routers.
IMO man-in-the-middle attacks are almost unavoidable
The main problem is that the control data in 802.11x is never encrypted.
Because every wireless authentication must start using the unencrypted control sequence, it will be ...
10
TL;DR: FaceNiff probably exploits WPA's "Hole 192" and uses ARP poisoning to set up a Man-in-the-Middle attack. The steps, in short, are:
Eve uses the Group Temporal Key (GTK) to inject ARP packets into the network, with the network's gateway IP paired to her MAC address.
Clients register Eve's MAC address as their new gateway.
Clients send packets ...
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