Questions tagged [handshake]

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19
votes
3answers
5k views

Can attackers change the public key of certificate during the SSL handshake

The communication is not encrypted during the SSL handshake. If an attacker conducts a man in the middle attack between server and client to capture the certificate, and change the public key in the ...
4
votes
1answer
220 views

Circumventing Netflow's visibility on SSL traffic

In a SSL handshake, the hostname is visible most of the time as it is needed to validate the certificate over HTTP. Netflow is thus able to pick up the common name from the certificate exchange, ...
3
votes
1answer
301 views

Is it possible to make HTTPS 0-RTT with help from DNS?

This article gives an implementation of encrypted SNI where a public key is retrieved from the DNS. It feels like cheating but imagine this: If the server publishes its certificate on its DNS record, ...
3
votes
1answer
13k views

HandShake TLS- Certificate Unknown

I have added the necessary certificates to communicate a web service by TLS, both the client and the server added the certificates to the keystore, but in the handshake, certificate unknown is ...
3
votes
1answer
123 views

TLS 1.2 Handshake: Does the server have to take all extensions sent by the Client?

I am unsure about how extensions are handled in TLS v1.2. During the handshake, the client is able to add some extensions during ClientHello. As far I understood, the server can pick arbitrary ...
3
votes
1answer
90 views

Why can SSH negotiatie two different encryption and authentication algorithms?

I recently found out, that according to the RFC, SSH can negotiate two different cipher (and MAC) algorithms for server-to-client-encryption and for client-to-server-encryption (check section 7.1. for ...
3
votes
1answer
610 views

What are the factors making a WPA2 handshake suitable for cracking?

Days ago I was dumping handshakes of my APs using airodump-ng. I would later use aircrack-ng to crack them using wordlists which would purposely contain the passphrases. However, I noticed that some ...
3
votes
1answer
241 views

Authentication handshake between two independent apps

I need help on a solution for below scenario from a security perspective. Scenario: There are two independent web applications App1 and App2. User will log in to App1 by performing authentication ...
3
votes
0answers
461 views

Raspberry Pi (Raspbian) not capturing WPA2 handshake with Aircrack-ng [closed]

I've been using Aircrack for a short time now with my Alfa wfif adapter on my laptop and it's been working perfectly. However when I try and do the same thing on my Raspberry Pi it's having issues ...
2
votes
1answer
169 views

Does the SSL record protocol encrypt the handshake protocol too?

As I know the first communication protocol which establishes between client and server in SSL is handshaking protocol and as this site says: The SSL record protocol is used to transfer any data ...
2
votes
2answers
8k views

What is the Session ID parameter indicate in Client Hello and Server Hello messages

I was trying to understand the TLS handshake in depth. I set up Wireshark and captured the github.com traffic. While inspecting the Client Hello and Server Hello, I found a parameter Session ID. ...
2
votes
4answers
10k views

How long til a 4-way handshake is captured with Aireplay-ng

I've got a TP-Link TL-WN722N wifi adapter which I believe allows monitoring/injection to a network (was reassured by the comments of other users). When I follow a guide by Vulnerableuser I can get to ...
2
votes
1answer
125 views

Is it possible to setup 1-way TLS client authentication without server certificates?

Is it possible with TLS to only authenticate the client? In other words can one-way TLS be setup in such a way that only the host initiating the connection uses a client certificate and the second ...
2
votes
1answer
330 views

In TLS 1.3 handshake, can an internal error at the client be interpreted as a decrypt error at the server?

In TLS 1.3 handshake protocol, the client sends the ClientHello message to the server. The server then sends back the ServerHello message followed by some encrypted messages. The client then computes ...
2
votes
2answers
88 views

Handshake without asymmetric encryption

One of my teacher said "Without asymmetric encryption, we would be forced to use third-party to initiate any connection". I don't understand how it can be possible, what if an attack occur during the ...
2
votes
1answer
144 views

TLS handshake random bytes reused

What would happen if the random bytes provided by the client and the server in the first two messages would be reused by one peer/by both peers? I think it would highly reduce the provided security, ...
2
votes
1answer
269 views

TLS 1.2 Missing Finished Message

I'm setting up a TLS connection for the purposes of sending secure SIP. The remote gateway (Twilio) doesn't always send a finish message and as such those requests fail. Everything else appears to ...
2
votes
0answers
41 views

Which messages are included in (D)TLS Finished message's verify_data field for session resumption

The https://tools.ietf.org/html/rfc5246#section-7.4.9 states which messages are included for PRF computation that is included in Finished messages It is clear for 'regular' (initial) handshake But ...
2
votes
0answers
774 views

Airgeddon-ng Handshake fail [closed]

I've followed the following instructions below. This is a freshly installed Parrot OS, not using VirtualBox and etc. I am also using Alfa AWUS036NHA wifi adapter. ifconfig sudo airmon-ng start wlan1 (...
2
votes
0answers
87 views

WPA technical doubts (3)

This is the third post about the set of doubts that came up when I tried to understand WPA3. I am new to this world of cyber-security so every bit of help is welcome! Someone told me that in WPA2 ...
2
votes
0answers
227 views

Why WPA2 did not design a PTK based on asymmetric cryptography?

I was shocked to learn how the PTK is crafted from the PMK in WPA2 WiFi. PMK is made with crypt_hash(SSID + PSK). OK, seems good. Then, the client and the Access Point (AP) make the famous 4 way ...
2
votes
0answers
78 views

What forces SSL exchange to require my smartcard to finish handshake

First, I hope that this is a legitimate question because it is spawned by what I am experiencing and what is happening. The environment is as follows... I have an apache reverse proxy, that I stood ...
1
vote
2answers
936 views

Do TLS standards require the server-side preference to always be used when negotiating ciphers to use?

Someone told me the other day that the TLS standards require the server-side to always have the authority to decide which mutual cipher to use when negotiating with a remote client. This makes sense,...
1
vote
2answers
2k views

Where is Hashing Used in the TLS Handshake

I understand the basic steps in the TLS handshake. My question is, where and how does one-way hashing fit into the steps below? Is it the session key that is hashed? Many texts mention that the ...
1
vote
1answer
48 views

Is it possible that a single handshake can have 2 TLS versions included?

I am seeing different TLS versions (1.3 and 1.2) in the handshake and intermittently it fails with this error: TLSv1.3 (OUT), TLS handshake, Client hello (1):. 2020-05-28T14:44:00Z.664 [thread-...
1
vote
2answers
124 views

Decide for client certificate auth in https based on hostname or url

Let's assume this (made-up) scenario: I install a webserver that reacts on two hostnames (anonymousserver.com and authenticatedserver.com) I would like the following behaviour: If the webserver is ...
1
vote
1answer
113 views

how are symmetric keys generated in TLS [duplicate]

My confusion stems from reading that TLS handshake uses some kind of Diffie Hellmann, when I was certain that the symmetric key was generated by a digest of earlier packets encrypted with clients ...
1
vote
1answer
786 views

TLS-Handshake, Server Key Exchange, Diffie-Hellman: Where does key length come from?

Where does the key length come from? In this example it is 2048 bits long: Secure Sockets Layer TLSv1.2 Record Layer: Handshake Protocol: Server Key Exchange Content Type: Handshake (22)...
1
vote
1answer
982 views

Sniffed SSL/TLS decryption : handshake necessary?

I read some topics where people claim to be able to decrypt SSL/TLS communications just by having the private key of the recipient. But, I recently learned that a public key can, but should never ...
1
vote
1answer
79 views

How is the MIC (message integrity code) generated in WPA2?

We know that in WPA2's four-way handshake, a MIC is generated in order verify the supplicant (client). But how it is generated? Is something hashed to get the MIC? The PTK (pairwise transient key) ...
1
vote
1answer
87 views

TLS- Key exchange for session keys. Why?

I have a question about the Key Exchange Algorithm used in TLS process. I have read that the Key Exchange algorithm is used by client and server to exchange session keys. Do the client and server ...
1
vote
1answer
78 views

Does a TLS client needs to support one of the named groups (curves?) supported by the server for TLS handshake to succeed?

Does a TLS client needs to support one of the named groups (curves?) supported by the server for TLS handshake to succeed? Longer version: I'm running a web site using Windows Server 2016. The web ...
1
vote
2answers
2k views

SSL handshake not visible in Wireshark

In my organization we have a cloud proxy that work on a loopback address. The vendor of this proxy has deployed an app on our machine which listens on the loopback address. I have captured the apps ...
1
vote
0answers
64 views

SSL Handshake in Android via Bluetooth Classic [closed]

I am working on implementing an Android App (client) which will be connected to Raspberry Pi (server) via Bluetooth Classic. To make data transfer securely, I want to implement SSL encryption between ...
1
vote
0answers
48 views

How does BLE secure connection ensure man in the middle protection?

I understand BLE secure connection pairing mode is improvement over Legacy Pairing. The issue with legacy pairing was intial TK value can easily be bruteforce by an attacker. In contrast, in secure ...
1
vote
0answers
57 views

How are symmetric encryption algorithms tracked once handshake is complete in common secure communication protocols?

My understanding is that most secure web communication protocols ultimately want to agree on a symmetric encryption algorithm to use for sending and receiving data. Once an algorithm is agreed upon by ...
1
vote
2answers
155 views

Key reinstallation attack how does it work without a pre-shared key?

The author of the key reinstallation attack released scripts on Github to test AP and clients. To test the clients, you have to connect to a fake AP but you still need to know the pre-shared key. Of ...
1
vote
0answers
500 views

SSL/TLS handshake potential vulnerabilities [duplicate]

After handshake one could be assure that data are encrypted and secure. But before that, handshake parameters are transferred via not secured channel. One could be MitM during the handshake procedure....
1
vote
0answers
286 views

what is the logic in choosing a certificate chain during a “server-hello” message in a SSL/TLS handshake

In a client-server ssl handshake, my server sends a certificate chain back to the client in a server-hello message. But I want to understand as to how that particular certificate chain is getting ...
1
vote
2answers
3k views

Airodump-ng doesn't capture handshake or sees any devices connected on Kali, but captures everything on Backtrack. How to fix it? [closed]

I ran into a problem in using kali linux system. Kali doesn't allow me to see any devices connected to certain spot or capture any handshakes, I know that it can capture them(and see connected ...
1
vote
1answer
90 views

TLS 1.2. Handshake: Where do Client and Server negotiate how the master key is built from randoms and pre?

I am currently trying to solve an exercise where I should look at a TLS 1.2 handshake trace while having access to pre and both randoms (server random and client random). In order to decrypt ...
0
votes
1answer
99 views

How SSL Handshake recognise any attack

I already know that a replay attack on an SSL handshake is ineffective, but if we suppose that an "intruder" has listened and has got all of the information from a previous handshake, how will the ...
0
votes
1answer
315 views

How does client verify the certificate provided by the server which is signed by different intermediate CA

I am creating a c++ secure client-server application using openssl library. I am still not clear about some aspects of the SSLHandshake procedure I have enabled Mutual TLS in-order verify the both ...
0
votes
1answer
237 views

SSL server sends wrong certificate when accessed via Java

In my project I have to integrate with another system which uses quite specific SSL (and also specific cipher suite). Here's what I mean. Whenever I try to access the server with Java (send a request)...
0
votes
1answer
74 views

What is the relation between “signature_algorithms” handshake extension and TLS ciphersuite

I am learning TLS handshake and find client/serve will negotiate a cihpersuite during client/server hello. Usually, the last part of a ciphersuite is a hash algorithm, like SHA256 in ECDHE-ECDSA-...
0
votes
1answer
372 views

What is the role of leaf certificate private key In TLS handshake [duplicate]

What is the role of leaf certificate's private key if this certificate is signed by the intermediate certificate's private key and the certificate signature will only be validated using its public ...
0
votes
1answer
88 views

Is Certification path construction algorithm needed for SSL/TLS?

In the TLS Handshake a Certificate message is sent. This message contains the (chain of) certificates needed to validate the provided certificate of the communicating party. However, I have also ...
0
votes
1answer
71 views

Do wifi access points and routers get some kind of data from devices when a device is able to see them?

I was wondering if when a router is broadcasting its signal, it is able to handshake with devices that are wifi enabled and looking for a wifi network to connect and get some info from them?
0
votes
1answer
211 views

Can do I brutefore wifi password with handshake without wifi detection? [closed]

I have captured handshake but now I want to bruteforce wifi without detection it (in different place). Is it possible? If yes, how to do that?
0
votes
1answer
1k views

Finding wpa2 key length

Is it possible to determine WPA key length through a successful handshake? Below is a screen capture showing the packet capture session of interest as displayed in Wireshark: My question came from ...