Tagged Questions

SSL (Secure Sockets Layer) and/or TLS (Transport Layer Security)

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2
votes
3answers
2k views

Uploading files through an HTTPS web application

We have a client facing web site. A certificate is required to land on the login page, where upon you then need a username and a password to further login. System has Apache servers acting as load ...
5
votes
1answer
386 views

SSL - Null Prefix Attacks Still Possible?

At DEFCON 17 (2009) Moxie Marlinspike gave a talk were he was able to use a malformed certificate signing request to get SSL certs signed for domains he doesn't own. The gist of it was that for the ...
2
votes
3answers
959 views

SSL vs Encryption

I am working on creating an android mobile application which needs to connect to a server from time to time. The application makes use of sensitive data which I would not like to get into the wrong ...
9
votes
2answers
13k views

Specific risks of embedding an HTTPS iframe in an HTTP page

I need help listing the specific risks of embedding an HTTPS iframe that enables credit card checkout inside of an HTTP page. Are there security issues with embedding an HTTPS iframe on an HTTP page? ...
6
votes
2answers
181 views

Should I test my SSL certificate for “RSA Shared Primes” before using it?

There are several papers from 2012 that say it's possible to factor several moduli by factoring shared primes. The link above includes python sourcecode to verify and test for this fact. Given this ...
9
votes
3answers
5k views

Can someone explain a little better what exactly is accomplished by generation of DH parameters?

I'm setting up a node.js server: https.createServer({ ... ciphers: 'ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH', honorCipherOrder: true }, app).listen(443); ...
15
votes
3answers
780 views

Can a nation-state adversary perform a MITM attack by compelling a CA to issue them with fake certs?

As I understand it, with any encryption system based on a trust chain / CAs (eg SSL, TLS, S/MIME), it would be possible for a nation-state adversary (such as the NSA) to compel the CA to issue them ...
1
vote
2answers
511 views

Why is malwarebytes.org's SSL certificate from someone else?

I tried downloading and updating malwarebytes from https://www.malwarebytes.org but their certificate seems to be incorrect. This is the warning: This is probably not the site you are looking for! ...
5
votes
2answers
227 views

Configuring election website to prevent MITM attacks

Consider an election web site that will be used for voting over the Internet. What steps should the administrator of such a web site take to provide adequate security against man-in-the-middle attacks ...
13
votes
2answers
1k views

Is there a tool to verify browser TLS/SSL configuration

I am looking for a tool to verify the configuration of ssl/tls settings in the browser. I have found a few sites that enumerate supported ciphers and the preferences but none of them seem to provide ...
4
votes
3answers
603 views

In what way is a partially encrypted webpage insecure?

What are the potential vulnerabilities that might arise if a webpage is only partially encrypted. I can think of 2 possibilities: You can change the non-encrypted parts of the page (HTML, CSS, ...
2
votes
1answer
692 views

Are there any vulnerabilities when making cross-domain HTTP requests during an SSL connection?

I recently starting using the Calomel SSL Validation plugin for Firefox to test the SSL security on the sites I visit. When navigating to American Express' log in page, I noticed Calomel reports the ...
4
votes
1answer
598 views

Do I need to keep certificate signing requests and public keys?

I've created an RSA key. Created a CSR. Got it signed and now I have my certificate. It's for a webserver running https. The public key can be generated from the private key, so I guess I don't need ...
1
vote
1answer
644 views

Possible to limit server connections to clients with a specific certificate?

Usually when I read about SSL and HTTP it says that the certificate is set up to authenticate that the host is who it says it is. Is it possible to configure the host to prevent it from processing ...
27
votes
2answers
1k views

Why aren't infinite-depth wildcard certificates allowed?

As far as I can tell, an SSL certificate for *.example.com is good for foo.example.com and bar.example.com, but not foo.bar.example.com. Wildcards certificates cannot have *.*.example.com as their ...
6
votes
2answers
659 views

Why do embedded systems store server's public certificate in ROM?

In the home automation scenario, smart gateway can bridge the many smart devices with Internet. In many cases, a server's public certificate is stored in the embedded system's ROM during ...
14
votes
2answers
3k views

How does non-ephemeral Diffie-Hellman key exchange become compromised in SSL when the RSA private key is leaked?

From my understanding, one of the major reasons we recommend Diffie-Hellman Ephemeral (e.g. DHE or ECDHE) over non-ephemeral DH, for SSL / TLS, is that compromise of the RSA private key (i.e. private ...
3
votes
1answer
437 views

Why isn't TLS just called SSL v 4.0?

SSL and TLS seem to be somewhat interchangeable. So much so that they are generally lumped together ("SSL/TLS") when referring to HTTPS and other services. Its almost as if TLS is version 4.0 of SSL. ...
22
votes
9answers
4k views

Is encryption in HTTPS done by the browser or by the system?

This may be a common sense question, but I am not able to find any documentation on this after searching on google for a long time When browser makes a HTTPs request, does it encrypt the data then ...
8
votes
1answer
482 views

Build a secure channel without SSL/TLS

I'm looking at possible options to build a secure channel between multiple embedded devices with limited cryptography capabilities and an HTTP server (It could be some sort of web service). 1. ...
6
votes
3answers
444 views

How to fuzz proprietary protocol over SSL?

I'm doing vulnerability research on a client/server architecture that uses a custom proprietary protocol sent over SSL (port 443). I need to be able to intercept the traffic, and be able to view it in ...
2
votes
0answers
74 views

How does Perfect forward secrecy work in https? [duplicate]

How does Perfect forward secrecy work in https? How to check whether it is enabled or not? Which big site actually use this? Paypal? Facebook? Amazon? I have read this Wikipedia article, but I don't ...
1
vote
1answer
342 views

SSL: MITM possible if private key is known? [closed]

If a Man-in-the-middle has the private RSA key of the SSL encryption. It should be possible for the Man-in-the-middle to decode the entire HTTPS datastream right? So, then the encryption is ...
6
votes
3answers
2k views

Is it possible to pass TCP handshake with spoofed IP address?

Little time ago, me and my friends argued if TCP handshake can be passed with a spoofed IP address. Assume I have a https web server that allows only admin's IP numbers. Can anyone connect that web ...
3
votes
3answers
325 views

User agent information from HTTPS flow

We are categorizing the network traffic, like determining if it is Facebook, Yahoo etc... Now I have been asked also separate mobile devices (like iPad, Nexus, iPhone). It is easy to do that in HTTP ...
1
vote
1answer
152 views

Dangers of client & server package, communication over HTTPS using user's own self-signed certificate?

I want to create a client & server package with the option of an encrypted connection. From my limited understanding, to get HTTPS connections working, the user needs their own certificate ...
4
votes
2answers
4k views

Certificate Chain checking

I have a very specific question. A client verifies a sever by taking the certificate and checking specific values and that the digital signature of the intermediate CA is correct (According to the ...
2
votes
3answers
887 views

When to use SSL ? / When to send passwords via mail?

Self-Proclaimed Experts are quick to say that for every time a password is being transmitted from a webserver to a user and vv, you need to use SSL. Because there will be people each time trying to ...
5
votes
2answers
3k views

Chrome does not show green bar with EV SSL but firefox and IE does

I just installed a EV SSL certificate on my server. It has been done correctly and is working, the issue is that Chrome does not show the company name in the green address bar, just shows the green ...
4
votes
2answers
866 views

Is it possible to create a secure chat web application relying on HTML5 web sockets?

Is it possible to create a secure chat web application using just HTML5 and Javascript? What possible security holes would there be if the server doesn't store the messages, just relay them using ...
2
votes
1answer
837 views

how to make socat ignore client certificate?

I'm trying to set up a listener to check if an application checks the server's certificate (I'm strongly assuming it is not). So I've created a self-signed certificate fake.pem for a listener and am ...
9
votes
4answers
3k views

How likely/possible is it that the NSA have broken common encryption techniques such as SSL/TLS?

Jumping on the NSA/Prism questions bandwagon - There's been a lot more attention drawn to facilities such as Room 641A which indicate that the NSA has been, amongst other things, applying mass ...
0
votes
3answers
927 views

SSL vs TLS, which is less vulnerable to DOS attacks?

When I learned TLS does not allow a connection to be created until it is has finished a secure handshake, i figured that would make it better for preventing DoS attacks. However, all I seem to find ...
2
votes
1answer
344 views

Is there a Skype plugin that uses TLS and ZRTP

I'm curious, if one can upgrade the security Skype offers to avoid a man in the middle snooping in on the calls by both parties using a client side plugin? Does one exist for this purpose? A bit of ...
1
vote
1answer
642 views

What is the difference between an HTTPS traffic setup with Stunnel and a SSL-VPN

We have a scenario where we cannot connect to our stunnel server running on port 443 on our network, which only allows access to Internet via a proxy server. On the contrary, when we tried a SSL VPN ...
3
votes
1answer
1k views

MITM and replay attacks prevention

I have a client (a mobile app) and a server, the app connects to the server via SSL. The server uses a self-signed certificate, and the client has a file (I'm not entirely sure what, something to do ...
13
votes
3answers
1k views

Multi-tenancy, SSL Certificates, and Subject Alternative Name

The X509 specification allows a CA to issue a single certificate for multiple hostnames, by using the "Subject Alternative Name" extension. From the spec: The subject alternative name ...
3
votes
1answer
751 views

How to MiTM insert an iframe using burp or another tool?

So, I am trying to obtain a cookie without the secure flag enabled over HTTPS. After reading about it, I came across an answer: You visit https://secure.example.com/ which drops a cookie on your ...
5
votes
2answers
1k views

Is it possible to force a new SSL session

Using tools like Wireshark, it's possible to decrypt SSL traffic as the client by logging the (pre)master secret, without using a mitm attack or the server's private key. But I found that for some ...
1
vote
1answer
111 views

Secure authentication cookie for web site

Hello i want to know if this auth token is secure enough for a site of millions of logged in users: ...
7
votes
2answers
1k views

Is “Fingerprint Check” enough to verify HTTPS certificates?

So I'm at place A, see this sign: and I'm writing the fingerprints to a piece of paper (this website is just an example): Ok. Then, I go to place B (other country, etc.) then I check this ...
9
votes
3answers
229 views

What simple security considerations can I / should I make for a read-only API?

Right now I'm setting up an API, to be consumed on the client-side to set up a directory site. I'm wondering what extra steps I need to take just to prevent people from gaining write access to the ...
5
votes
3answers
677 views

Why do we allow SSL certificates to be replaced before their expiry date, without revokation of others?

Imagine a situation where a rogue CA creates a certificate for your site. Since the user's browser trusts the CA, it will accept the certificate without any fuss. However, the site's real certificate ...
2
votes
1answer
71 views

Remote network security option

I'm a bit confused with some different network security techniques. Say we want a secure communication with a particular mail server in a remote company network. Reading and sending mails should be ...
6
votes
3answers
525 views

Security implications of an exploited router

So I completely understand that routers and local networks need to be kept locked down, etc. What real security threats can come about from an attacker who has remotely accessed (telnet or web gui) ...
2
votes
3answers
3k views

Can attackers steal SSL certificate from server and use it for MITM attacks?

I'm writing an iOS app for private use to acts as a client for a PHP server. To secure the connection I'm using a self-signed SSL certificate. Since the server is self-hosted, on the first connection ...
4
votes
1answer
849 views

TOR detection in network

After I read this link, I tried to understand how they manage detect TOR traffic The most understandable source for me was this paper He is saying TOR trafic can be detected by port, cipher suite ...
3
votes
2answers
864 views

Change 'Key Usage' of a certificate

Is it possible to change the 'Key Usage' property of an existing ssl certificate of a web site? Our goal is to host a web service so that a third party can integrate with our solution, and their ...
5
votes
5answers
3k views

How secure is using CRAM-MD5 for email authentication, when not using an SSL connection?

Background: My current server-provider tells me it's no problem to store the passwords in plain-text in the database, saying he has to do so because they use CRAM-MD5 for email authentication. My ...
2
votes
2answers
2k views

Force SSL/TLS client cert authentication even if server does not request it?

Usually the server specifies in the Server Hello message if a client certificate is needed/wanted. Does anybody know if it is possible to perform an authentication via client cert if the server does ...