Questions tagged [protocol]

A system of rules designed to allow the communication between two or more participants. The two main types of protocols are either stateless protocols (UDP) or stateful protocols (TCP).

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7
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2answers
1k views

Router's serial port only outputs garbage

I'm trying to reverse engineer a 2Wire ADSL modem/router, mainly for practice. I opened it and found a serial port (with a header conveniently already in place) but I'm not getting any useful data out ...
7
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1answer
966 views

Reverse engineer TPMS sensor data

I'm trying to reverse engineer data received from TPMS (car tire pressure) sensors. I was able to receive and demodulate the data (433 MHz, FSK, Manchester encoding). Probable packet fields: bytes 1-...
6
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1answer
334 views

HackRF One - Replay Attack on Garage Door does not work (12 DIP switches)

TL;DR solution Setting 4MHz sample rate and 2Mhz bandwidth in the capture tab (according to the Nyquist theorem the sample rate has to be double the bandwidth) Using the length of a DIP switch ...
5
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0answers
604 views

Reverse engineering an hydrometer's Bluetooth communication

This is a very specific question. I'm currently working on a project to create an android application capable of reading the values of an hydrometer via Bluetooth. By reading the datasheet, I suspect ...
4
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3answers
365 views

Modern tools for reversing binary network protocols

What are some modern tools or techniques for attempting to reverse a binary protocol sent over UDP? I've been trying to do research on this, and it seems like almost everything is obselete. Previous ...
4
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2answers
1k views

Reverse engineer 4-bit checksum (?) in Sanyo air conditioning IR packet

I am reverse engineering IR protocol of Sanyo air conditioner. AC sends the whole current state of remote on each key press. Data sent is 67 bits long, last 4 bits seem to be the some kind of error ...
4
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0answers
333 views

Trouble finding the right Checksum algorithm

After reading a lot of posts here and their solutions, Punching lines in CRC calculators for several days now. I can't seem to find on which Checksum this code is based. Background This is a data ...
4
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0answers
865 views

How to find a login packet structure (client-side only)? [closed]

As Google did not yield any results, I decided to ask it here. I'd like to reverse the login sequence of a game (using gamespy). In this login sequence, first the game uses the gamespy protocol (...
3
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1answer
273 views

What Checksum/CRC algorithm in RF packet?

I am banging my head to figure out the checksum of a RF device, it seems to be a simple one but no luck so far... The first 3 bytes is the SyncWord then 9 bytes is the payload and the last byte ...
3
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1answer
432 views

How to analyze packets?

I have a packet that I want to analyze which consists 16 bytes. I can produce as much as of these packets needed to analyze. Even though packet does the same thing on application the data in the ...
3
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1answer
153 views

Is it possible to sniff an ATA Drive password?

Context: I have a proprietary Tandberg Data RDX QuickStor Internal USB3 drive bay for PC (item number 8666-RDX) and some storage cartridges for it. Esentially, these are just regular TOSHIBA MK3276GSX ...
3
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1answer
278 views

Decipher variable length serial protocol

I have an ebike consisting of a controller which regulates power to the motor and a smart LCD which can adjust max speed, power output, pedal assist sensitivity etc as well as displaying the current ...
3
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1answer
356 views

NFC Tag reverse engineering failed by a non-responding tag

I was curious about a system using NFC and I tried to find out what was the protocol. But after digging few days around, I have the card detected by my reader (acr122u) but that's all I get. I can't ...
3
votes
1answer
907 views

Reverse engineer checksum algorithm

I am trying to reverse-engineer the protocol used between my Air-conditioner and the wired control unit on my wall. (In order to have my home automation be able to monitor and control the A/C.) The ...
3
votes
1answer
950 views

Reversing serial RS485 half duplex bus protocol understanding

I have a master & slaves setup in which the slaves only respond when spoken too. I can snoop & record an existing master/slaves conversation. I have an extra slave device that I would like ...
3
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1answer
82 views

On reverse engineering an udp protocol to control a drone

My goal is to control my drone with my raspberry pi using python and not the app that is being delivered together with it. First I connected the app to the drone, flew and used aircrack-ng to get the ...
3
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0answers
128 views

Reverse engineering non-standard LIN protocol

I'm trying to reverse engineer an ECU / GSU protocol from a model airplane jet turbine, in order to make a telemetry adapter. I have decoded several other protocols in the past with good success but ...
3
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0answers
1k views

Reverse engineering unknown RS232/UART binary protocol

Background story For couple of days I'm trying to crack the protocol used the old medical device, in order to collect data for a research in an automated way. The device in question is Novametrix ...
3
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0answers
124 views

CRC with OR but seed differ every time the protocol restart

It's some days I'm trying to understand how this protocol works without any success. I need some help. Basically I'm sniffing an UART signal. 115200 8N1 I understood what's happening under the hood ...
2
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2answers
1k views

Identifying protocol in a pcap file?

Is it possible to identify a protocol in a pcap file? I have a file which is a capture of data going between my phone and an IP camera, and I'd like to identify the protocol. I am using the app "MEye" ...
2
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1answer
778 views

Deducing Protobuf Schema and Datatypes

I have a number of protobuf files but no .proto schema file! cat myfile.pbuf | protoc --decode_raw > outputfile.txt Using the above command, I was able to decode the file into a somewhat readable ...
2
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3answers
2k views

How to monitor/reverse engineer RS485-connected display device traffic?

Can anyone point me in the right direction for tutorials etc on reverse engineering RS484 connected battery management system? I have a large 12V lithium battery module which has an internal BMS and ...
2
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2answers
689 views

Reverse engineer DB25 protocol

I have a device that consists of a machine and a control head, connected with a cable with Dab25 connectors at both ends. The control head contains various buttons and dials for operating the dip ...
2
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2answers
264 views

Understanding a messengers protocol encryption

For my own personal curiosity and development (building a bit of code mimicking the protocol), I am trying to figure out what the communication protocol encryption is made out of in a particular chat ...
2
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1answer
231 views

UE Megaboom serial protocol

I recently got a UE Megaboom Bluetooth speaker. Apart from various audio profiles, I noticed the speaker also exposes a Serial Port BT profile. I suspect this is the channel the app uses to control ...
2
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1answer
96 views

Can't identify checksum type in unknown RS485 protocol

I need to reverse a RS485 protocol in order to extract some values for further usage. Unfortunately only these few messages are available at the moment. They repeat continuosly. Only in special ...
2
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1answer
2k views

Calculating check sum of m-bus data frame

I'm trying to calculate the check sum of a m-bus data frame. In page 1 of this PDF I'm able to read that the frame's check sum "is calculated from the arithmetical sum of the data mentioned above, ...
2
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1answer
787 views

How to identify HTML5 geolocation protocol of a browser? [closed]

I've been trying to figure how a html5 browser like chrome or firefox performs geolocation under the hood but I'm running into some difficulties. Difficulties To be more precise, I want to know what ...
2
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1answer
80 views

How to determine a type of binary serialization?

I'm trying to analyze the messages that the game sends to the server through WebSockets. I have a simple WebSockets proxy that stands in the middle and prints all messages to the console. I noticed ...
2
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0answers
137 views

serial protocol patterns

I am reversing a serial 232 protocol and I found these pattern in the data. E5 A7 CD 01 00 79 .. .. 40 00 23 00 23 00 23 00 23 00 22 00 22 00 22 00 21 follows some recording and expected approx ...
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0answers
640 views

Reverse engineering TPMS sensor data [closed]

I'm trying to reverse engineer data received from TPMS (car tyre pressure) sensors. I used rtl_433 tool to capture the data from sensor at 433 MHz. Tool was able to detect data is using FSK modulation ...
2
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0answers
402 views

Finding the h.264 stream in a bytestream

I have a bytestream that contains h.264 bytestream packets in it. How can I find it? Output from stream: https://mega.co.nz/#!3llAnLaQ!pc1JPDpDOP6948F2x44LqeYm-p5CDnb91Da334rt4fY The first 13 bytes ...
2
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1answer
131 views

Safecom TA-810 protocol (having trouble with the CRC)

(i've also posted this question on stackoverflow before i found out there was a specific stackexchange site for reverse engineering. My bad. Original post here: https://stackoverflow.com/questions/...
1
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1answer
861 views

Decrypt SSL/TLS traffic from a Java web applet

I am trying to reverse engineer the protocol of a chat written in java to implement my own client. The official client is a java applet embedded in the website so I thought it might use just https but ...
1
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2answers
2k views

DPFMate Keychain tool

Got this Digital Keychain Photo viewer thingy. Comes with the DPFMate.exe software, which does not run under Windows 10. So far I've confirmed, that it runs perfectly on what they avertise - Windows ...
1
vote
1answer
348 views

What checksum algorithm is this network protocol using?

I've been working my way through an undocumented TCP-based protocol by monitoring traffic with tcpdump, Wireshark, and some Python packages (scapy, numpy) with good luck so far, but I've hit a wall ...
1
vote
1answer
266 views

Understanding decoding communications over interfaces

I'm currently in the middle of trying to decode the communication of an hydrometer. Thanks to a previous question made in this site I was able to find a PDF describing the communication of a different ...
1
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1answer
1k views

Books/tutorial on reversing protocol

Can someone recommend any tutoial or books on how to analyze unknown network protocol. Basically given the dumps of network traffic, I need some guide/examples on reversing the protocol.
1
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1answer
187 views

Reverse UART communication protocol

I'm objective is to build a custom wifi module to be used on a Samsung AC AR24HSFSAWKN. I have such an official module SWL-B70F for which I'm trying to reverse engineer the communication with the main ...
1
vote
1answer
86 views

What's wrong with my mitm to support rr commands with gdbserver on IDA?

First of here is the gdb remote protocol doc. The idea of the below script is the following - you enter an actual command (one that will be send as a direct packet see packets) in the gdb window then ...
1
vote
1answer
107 views

Checksum field within IR protocol

I am trying to reverse engineer the IR protocol for my air conditioner (GREE - remote control YAP1FF) and with the data I found online and a lot of testing with a IR receiver there is only one field I ...
1
vote
1answer
195 views

Methods for Reverse engineering proprietary protocol

I have a class of devices that I want to connect to. They use a protocol co-developed by a couple companies back in the day and was never published. Electrically there is only one wire which wraps ...
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4answers
1k views

XMPP clubs in league of legends

Hopefully I'm asking this at the right place. League of legends recently added the option to join a club. Clubs still use the XMPP protocol just like before for their public chat rooms: XMPP for ...
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0answers
158 views

Reconstructing struct/union-based IPC protocol wire format

I'm embarking on my first reverse-engineering adventure. I think I've picked a rather dense piece of steak to start out with. I have three C programs which communicate together using an unknown IPC ...
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0answers
43 views

Likely protocol determination by chip IDs and connections?

CONTEXT: My first post in this stack. Absolute beginner at RE. Also generally a beginner at anything electronics. Please be kind and correct me instead of ridiculing me. GOAL: Replace a damaged ...
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0answers
26 views

FFC on the back of a Chromebook Pixel Display Assembly

Hello! I want to get the touch overlay of a Chromebook Pixel Display Assembly to work. I attached a picture of the Cable coming out of a mxT1664S touch controller. Can someone tell me what type of ...
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0answers
119 views

Protocol RE, mysterious checksum function

Im trying to reverse engineer a protocol in which some text is sent and has a specific number appended. I figured out that the number is some kind of a checksum (depends on the text somehow) and also ...
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0answers
49 views

Reversing a serial communication with two inputs

I'm making a device that needs me to transfer some sort of initiation code like handshaking to start further communications. There is 2 inputs and 2 outputs the first output is pretty similar to a two'...
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0answers
850 views

Reversing network traffic and rebuild packets

I want to learn something about reverse engineering. I want to rebuild the TeamSpeak connection (client connects to server). I hooked the recv and send + encrypt/decrypt functions and logged the ...
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0answers
163 views

Trying to replicate a serial protocol

Spent the last few weeks reading, typing, testing, rinse & repeat to no avail in solving a problem. Problem: Trying to reverse engineer a serial protocol at work. Instrument is currently being ...