19

Packet checksums are not cryptographic measures, and are not intended to be a security feature. Anyone (even an attacker) can calculate the checksum for a packet containing anything, and there's no secrets/keys involved in the calculation. Checksums are intended to catch errors during the transmission of the packet: flipped bits, miscommunication, etc. ...


10

PART 1: Generic explanation, unnecessary to read if you have read the question. The first (how does the packet arrive at the attacker): Victim sends a packet with source IP '192.168.1.3' and source MAC '00:00:00:00:00:03' to destination IP 'DEST' and destination MAC '00:00:00:00:00:01'. Where 'DEST' is some external IP like '47.32.1.6' The router ...


8

Get to the roots ! If you know what ARP does, things will be clearer. On a subnet (machines plugged into the same set of hubs and switches), the machines talk to each other with MAC addresses: the MAC address uniquely identifies each ethernet/WiFi card. Machines, a priori, do not know MAC addresses; they just know IP addresses. So, when machine A wants to ...


8

By their function, a switch will only forward packets to the port where the destination computer (identified by it's MAC address) is. For this reason, they are said to mitigate sniffing attack. However, switches are not security devices but network devices. In order to know where a specific computer is, they have to learn where they are. For this, they ...


7

Not only can checksums be recomputed after a packet has been modified. This happens during normal operation of IP. It is not at all unusual for a router to have to update three different checksums on a packet before it will be able to forward an unmodified payload. The three checksums I am referring to are on the Ethernet, IP, and transport layers of the ...


6

If you have a https page, but load some assets (JavaScript) over plain http, then: Many browsers (recent Chrome versions, maybe also Firefox) won't even load the script by default an attacker can intercept the script, and replace it with — for example — another script that will simply copy the entire <body> contents of your https page, rendering https ...


6

You are assuming that once you are authenticated to the Access Point that you can automatically see all WiFi traffic from all nodes in the clear. In WPA, each node is given their unique key with which to communicate with the Access Point.


6

It depends on the class of the switch, for example: Wifi routers and home routers have LAN Isolation, however this one is usually disabled by default Layer 2/3 campus class switches usually have ARP filtering, but if it's not enabled than you can spoof MAC or IP address from different VLAN (you can use same MAC or different one for any IP address). The one ...


5

ARP is local to a network "wire". In traditional Ethernet, there was a single cable going through all machines in a LAN; the full network is then a collection of LAN, linked together through special machines (routers) who have several ethernet cards, one on each LAN to which the router is connected. When an IP packet must travel from machine A to machine B, ...


5

First, let's clarify what is meant by a static arp entry. The Address Resolution Protocol is used to map the layer 2 address to the layer 3 address, typically this is Ethernet and IP. A static arp entry means that you always expect a specific IP to be at a given hardware address. With a default Windows or Linux implementation, you will be using a TCP/IP ...


5

The attacker can try to flood the MAC table of the switch, and then the switch could fall down in "hub" mode. Then the switch would send the packets of Alice and Bob on all port. So Eve could sniff their network packets. Another way to hack is to poison the switch MAC table. If Eve knows the MAC address of Alice and Bob, Eve could tell the switch that he ...


5

The detect ARP spoofing, you typically capture packets and look for gratuitous ARP advertisements. That way you can also see what device is doing the spoofing. To defend, you need to configure your device/network with static ARP assignments.


5

I just happen to be writing a series of articles covering such network attacks from a practical point-of-view. Here is the article on DHCP, ARP will follow. DHCP and ARP are indeed two different attacks allowing the attacker to achieve a MITM within a subnet. DHCP Spoofing is done by a rogue DHCP server on the network which replies to DHCP requests ...


5

Scapy does not route the traffic, nor does it touch the traffic at all in this scenario. When you enable IP forwarding on a host, it becomes a router. When the host receives a packet not destined for one of its own addresses, it will route the packet per its routing table. Since the traffic from the victim has a destination IP address not matching the ...


5

This is actually not a security question at all. The question you want to be asking is how one node on a network can see the packets that are not destined for it. For this answer, you need to understand how Ethernet networking works. Ethernet networks are broadcast networks, meaning that every node on the same segment can see every other node's traffic. No ...


4

Suggest you research the latest Cisco APs. I believe these devices are able to isolate each wireless client from each other and from the network. All client traffic is routed instead of switched. You can then setup ACLs to keep WiFi attached clients from reaching anything they should not have access to. Also most enterprise-grade switches support anti-...


4

Question is : why the ARP modified versions hasn't been used on large scale yet ? What is the cost of addressing this versus the risk? ARP is a local subnet issue. If someone is already successfully on your LAN you probably have a much bigger problem because they can still do attacks at higher layers of the communications stack. Is this where you want to ...


4

Configure your switch to use Private VLANS (PVLANS). PVLANS basically say that physical ports Gi1/1 - 47 can only talk to physical port Gi1/48 (where your gateway is). Even things on the same subnet must go through the gateway to talk. In a setup with N hosts there is generally no reason for the hosts to talk so a PVLAN config is optimal for security. ...


4

According to my research on the subject, and running tests there are no quick fixes for tracking the source individual perpetrating this type of attack because of the nature of it. Meaning tracking, but not filtering/blocking. The attack method itself is basically easy to do compared to the scale of other types of attacks out there due to fundamental flaws ...


4

case 1 - Will only tell the target that you are the router. If you don't tell the router that you are the target, the router will send packets to the target, the target will send the reply to you, and it will stop there. This will effectively DOS the target because you aren't forwarding the packets to the router. case 2 - Is the complete ARP spoofing ...


4

Your assumption is mostly correct but not completely. As you suspect, cases (b) and (c) are the same because it is of no relevance whether the switch is built in to some other hardware or standalone. So I will call both cases (b). An ethernet switch will normally optimize the traffic flows so that packets are not sent to ports where they don't need to go. ...


4

Short answer: Switches only help when upgrading from a hub, don't add it to your network unless you need it. M'vy and GreatSeaSpider have given great answers!, I will try to simplify and show visually what they mean. It's all about collision domains! Image A explains what each device does, and Image B shows how that affects a network. (source: networking-...


4

You can do this using DNSchef. It is described here at the Kali Webpage. You can also find a useful documentation at the developers webpage. When it gets more complex I suggest you to use configuration files instead of command line switches.


4

By using disassocate packets. Those packets has the source MAC of an AP and force the client to disconnect and reconnect to the AP. By keeping sending those packets, you can keep any client away and unable to connect to this specific access point. Edit: A summery for people can't access links. From a tool named Aircrack-ng Deauthentication ...


4

There is no indication of ARP spoofing, at least not in the information you have provided. What you should see in case of ARP spoofing is that your default gateway has the wrong MAC address, i.e. you would need to verify the MAC address in this entry: 172.16.130.193 00-25-90-ea-31-33 dynamic Everything else are all perfectly valid entries: 224....


4

ARP spoofing is easy to detect. If a router sees an ARP advertisement packet for an IP address that it knows is already associated with a different port or MAC address, it can block it, shut down the port the packet came from, or take other appropriate action. Any decent IDS will pick up an ARP spoofing attack. All that said, I find that it's quite uncommon ...


4

Firstly, in order to do ARP poisoning you have to be connected to the wireless network you're going to poison responses on. You may already know that, but your question doesn't indicate that you know that's a requirement, so I wanted to make sure that it was clear. As for your answer: Simply put, ARP poisoning works because ARP works. The only thing that ...


4

Depending of the device, they may send who-has ARP request every Xs. (or in case they think they've lost connection with your router) This will result in your router giving back the correct mac address and the ARP cache of the victim will not be longer compromise. To counter that, you can sniff your network (eg using scapy) to check for ARP request ...


4

However, when an HTTPS connection comes in, it refuses to accept my certificate. That's expected. You are trying to man in the middle a TLS connection with a certificate which is either not issued by a CA trusted by the client or where the subject of the certificate does not match the hostname of the target URL. That's exactly the kind of attacks ...


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