Questions tagged [udp]

UDP (User Datagram Protocol) is a simple connectionless transmission model formally defined in RFC 768.

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Unknown NbtNS Traffic Leaving My PC

I was alarmed by the network monitoring team that there is some UDP traffic headed to the Internet on port 137 which was detected as SMB traffic by our monitoring solution. What is interesting is that ...
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66 views

Outgoing messages while under massive denial-of-service attack

As I understand it, there is no internet protocol that provides true broadcast like in say a card game or a partially synchronous network assumption. How close can internet protocols come though? We'...
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How Should Multiple Checksums Be Performed On the Same Data? [closed]

I am using CRC32 to verify the integrity of received UDP packets. Along with the generator polynomial, the sender will also specify how many checksums to perform on the sent data, as well as what ...
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34 views

Would adding `--data-string` to a UDP scan change the results?

I'm doing UDP scans on some internal servers and want to add a custom token (randomly generated string) to packets as much as possible in order to later filter out my scans from real non-testing ...
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1answer
167 views

HTTP/3 No more TLS or TCP [closed]

I was reading documentation about HTTP/3, and in the article, they sed that they are no longer TLS or TCP. So it's mean that a web site with no SSL 80 will be changed to what port and 443 will be ...
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3answers
366 views

Is there any alternative to nmap for UDP?

I know UDP Scan is very slow and there are a lots of parameters for nmap like, --max-retries etc. But i want to speedly udp port scan. I tried a lots of programs but not speedly. Any alternative nmap ...
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1answer
31 views

how do you find all upd connections a remote server has? [closed]

Given an IP address of a server connecting to unknown clients via UDP, is it possible to find the IP address of all connected sessions on that server? I do not have access to the server, I would like ...
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106 views

Will anyone figure out who I am if I am downloading torrent while logged in facebook in my browser?

I have protonvpn. I am downloading torrents. I don't want anyone to know that I am downloading torrents. I am also logged in to Facebook in my browser. So Facebook knows my VPN IP. And my ISP knows ...
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66 views

Using Noise Framework KK as alternative to DTLS?

I am trying to create a secure UDP connection in NET Core. Due to DTLS not being supported and it being quite the headache and existing libraries (DTLS.Net) are limited and inactive. Noise Framework ...
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2answers
108 views

What is the most powerful type of DDOS/DOS attack? [closed]

What I mean is what protocol are best to DOS something like TCP, UDP, HTTP?
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1answer
400 views

Server is sending large amounts of encrypted UDP traffic

The hosting company of a client has shut down their Windows server twice in the past week because the server seems to be sending out massive amounts of outbound encrypted UDP DNS traffic. I have now ...
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1answer
227 views

Why is SNMP vulnerable to IP Spoofing?

I read on Wikipedia's Article on SNMP SNMPv1 and v2 are vulnerable to IP spoofing attacks, whether it runs over TCP or UDP, and is a subject to bypassing device access lists that might have ...
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167 views

Why do firewalls focus on tcp and udp?

From what I can see, most firewalls seem to focus on tcp and udp. Why is that? Is it impossible or at least very unlikely for malware to use other protocols/custom protocols?
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324 views

Is UDP used for applications that require less security?

We often hear TLS over TCP socket and very famliar with its use case e.g. HTTPS. While I am learning Linux socket progamming, I read a An Introduction to OpenSSL Programming, Part I of II tutorial . (...
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1answer
73 views

UDP amplification: length(response_packet) < length(request_packet)

I was researching the GitHub DDoS attack of 2018, in which memcached UDP amplification was used. I noticed that a GitHub blog post referenced a CloudFlare post which described memcached-based UDP ...
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1answer
9k views

What is this service? [closed]

Fairly new to infosec and am going through a course on nmap. While scanning I found this and it looked interesting and was wondering if you all had any information on this? This is the port,state and ...
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2answers
710 views

Do I have to block UDP ports when I launch my own server with a public IP?

I am trying to give better security to my Raspberry sever. When I installed UFW, I allowed just port 80/tcp and my own high port for SSH communication, and by default are all others ports "deny". ...
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1answer
30 views

Why do processes on servers have socket types associated to the port number? [closed]

Why do some servers have TCP/UDP alongside the port they're listening to. To my understanding TCP and UDP are socket layers, they're methods of determining how the traffic is being sent over the ...
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1answer
1k views

What is the difference between DNS flood attack and UDP flood attack?

As title says, what is the difference between DNS flood attack and UDP flood attack? Plus, do they only exhaust the network bandwidth or do they also exhaust the server-side assets such as CPU, ...
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1answer
1k views

Encrypting UDP? (not using DTLS)

We are exploring options on encrypting messages to 3rd party devices which operate on UDP messages. Since each vendor will need to implement the encryption-decryption process as well, we would like ...
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2answers
410 views

How does DTLS replace the transport encryption of TLS? [duplicate]

I've been reading the RFC for DTLS over UDP, but can't seem to understand, how the transport encryption aspect of TLS was handled. It reads to me, like they just didn't bother, since there can be ...
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1answer
49 views

is -nU an option with nmap?

My coworkers seem to have -nU (no udp) as an option for their nmap scripts but I've never seen this in use and when I try to use this option with nmap, it does not work. I thought no udp was enabled ...
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2answers
345 views

One way protocol with encryption without tcp

I am trying to brainstorm how I might either: 1) create a protocol (although against this option) 2) use an existing protocol That does the following: 1) allows 1 way communication from 1 node to ...
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1answer
2k views

Vulnerabilities of DNS when utilized on a TCP port

There was some specific cyber security challenge (Cyber Cube 2018, GE). In one of the tasks, objective was to gain the access to some specific file that server included. After successfully solving ...
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Machine reaching out to Microsoft IP address using NBTstat command

I have limited logs for this event but the IPS says its a NBTstat query outbound over UDP port 137 to a Microsoft owned IP address. Should UDP 137 ever reach out externally? This is about all the ...
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1answer
349 views

Security implications of setting the broadcast flag on a UDP socket

Are there any negative security effects of setting the SO_BROADCAST option in a C UDP socket? I'm writing a C program and if I just set the broadcast option to 1 then all IP addresses work as intended,...
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1k views

UDP vs ICMP flood

How can we measure the efficiency of the flood technique? Will it be by the number of bots required for flooding the link? In case of UDP and ICMP, which one would be more efficient and why?
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Why is spoofing allowed in reputed VPS services?

I just learned about IP spoofing and so I set up VMs and sent spoofed UDP packets (8.8.8.8, Facebook's IP, Twitter's IP) to myself (home PC and mobile) from well-reputed VPS providers like AWS, ...
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2answers
1k views

How many UDP packets is too many?

My Company recently got hit by a spam email with a link that executed an .exe file. Apparently our Antivirus stopped it from executing (Symantec enterprise). I'm no security expert, but I am a ...
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2answers
800 views

UDP flood 300 Kbps + SYN probes / other attacks. Flood or DDoS at low rate?

So for over 2 weeks, Im receiving what appears a combination of attacks non-stop 24/7. First this UDP flood at a strangely small rate of 280 Kbps / 110 pps (360 bytes length) 02:29:41.978484 IP (tos ...
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2answers
2k views

Insecure/Obsolete TCP/UDP Ports? [closed]

I used CurrPorts to monitor TCP/IP network connections. This image shows when I don't connect to the Internet but I don't know why Avast Antivirus established this port. Is it insecure? This image ...
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1answer
321 views

How to handle UDP abnormally disconnection in DTLS?

DTLS-UDP is used between client and server. If the client ends abnormally,how does the server know that the client is gone? i have read rfc6347 and find nothing about that. thanks in advance.
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478 views

If TCP is more “secure” than UDP, how would a practical UDP “attack” look, for example during the initiation of a MS RDP connection?

In accordance to the recent question Why is TCP more secure than UDP?. How would an "attack" look when it comes to the practical aspect? A great example would be the use of TCP or UDP for Microsoft ...
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11answers
47k views

Why is TCP more secure than UDP?

While reading MS SDL (Microsoft Security Development Lifecycle) presentations I found a recommendation to replace UDP with TCP in applications because TCP is more secure than UDP. But both of them are ...
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1answer
369 views

How to block an application with iptable which use random port

Scenario: My goal was to allow TeamViewer to connect to my home workstation from my laptop only. So I have tried to bind my laptop's MAC with an IPtables rule as following, [arif@arif:~]$ sudo ...
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Spoofing an IP/MAC address to avoid ICMP Destination Unreachable being sent back [duplicate]

As far as I understand UDP flooding the idea is to send UDP packets across all ports from e.g. Alice to Bob, and get Bob's machine to check who listens to certain ports and generate many ICMP ...
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2answers
2k views

Using IPsec through NAT

I have read that it is recommended to encapsulate IPsec packets into UDP (port 4500) packets in order to circumvent NAT. Could anyone please provide a detailed explanation of the reasons behind this ...
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2answers
2k views

Authenticate a user thru a UDP socket

so let's say I had a basic socket, doesn't give you any information about the user other than the IP address, what would be my options If I wanted to authenticate a user in the most optimal way ...
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2answers
8k views

Windows firewall settings to receive UDP and pings

I use a windows 10 to receive UDP packets or pings from another computer which runs Win/Mac/Linux. I default, I turn off the firewall to receive pings or packets. I prefer not to turn off the ...
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1answer
552 views

Is it possible to scan the top X UDP ports and the top Y (X!=Y) TCP ports in Nmap using a single command?

Given X!=Y, is there any way to scan the top (--top-ports) X TCP ports and the top Y UDP ports using a simple Nmap command? The --top-ports parameter affects both the TCP and UDP scans (e.g., when -...
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2answers
158 views

Does the choice of protocol affect the efficiency of a DOS attack?

I was wondering, to make a DOS attack you need to send something to the target you are DOS-ing. And to send something you need to use some protocol. My question is, are all protocols the same speed? ...
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2answers
7k views

How realistic is it to spoof a specific UDP IP address? [duplicate]

Let's say that I'm a malicious user Bob and I have found a vulnerability in an application that will allow me to impersonate another user, Alice. Alice is connected to 'X' server with her IP address (...
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1answer
220 views

Client security using UDP

Introduction I am currently trying to build up a networking layer for Unity from scratch. Currently I am testing the communication via UDP using Node.js for the server and the client. However I guess ...
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1answer
2k views

Is it possible to successfully send a spoofed UDP header with a completely unrelated source IP?

I've read that many networks use ingress/egress filtering to eliminate the number of spoofed UDP packets sent and received by their network. Given that network provides have been much more diligent ...
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1answer
289 views

What is UDP port 56183

We seen suspicious probing from source port 53 to destination port 56183. May I know what services use port 56183 (udp)?
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1answer
75 views

Is it possible to get All IP's that belongs to given zip code? [closed]

For this kind of things can use Country IP blocker , but it only gives whole country IP's, so what im asking is , Is there any way to get All IP's that belongs to given Zip code?
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1answer
3k views

Does a Server connecting to port 3544 pose an increased risk

I had look at the firewall logs and i can see my production server connects to microsoft (13.92.90.48) on UDP port 3544. A quick reading suggests this is to do with Teredo tunneling (IPV6 translation ...
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No authentication, AES encrypted JSON over UDP

I was recently assigned the task of testing a new hardware device which communicates with a JSON API over UDP. For some reason or another, it was decided that AES-CBC-128 should be used to encrypt ...
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2answers
97 views

Find DNS Server of an IP over Internet [closed]

I know that many clients in the same network has a same DNS (Most of time but it can be changed.) But is there anyway to understand what DNS Server that an specific IP (Over Internet) uses through ...
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2answers
1k views

Minimum required processes with open ports on AWS?

I recently started an AWS box to be used for a public web site and it seems to have the following ports open... I was long ago convinced that it's a good idea to minimize the attack surface on any box ...