Questions tagged [openssl]

OpenSSL is an open-source implementation of basic cryptographic primitives, X.509 certificate utilities, and SSL and TLS protocols.

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52
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2answers
69k views

Decrypting TLS in Wireshark when using DHE_RSA ciphersuites

How can I decrypt TLS messages when an ephemeral Diffie-Hellman ciphersuite is used? I am able to expose the premaster secret and master secret from the SSL Client. Using that, how to decrypt the ...
245
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4answers
111k views

SSL3 “POODLE” Vulnerability

Canonical question regarding the recently disclosed padding oracle vulnerability in SSL v3. Other identical or significantly similar questions should be closed as a duplicate of this one. What is the ...
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2answers
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What should end-users do about Heartbleed?

What should a website operator do about the Heartbleed OpenSSL exploit? mainly talks about what people running websites should do about Heartbleed. What should end-users of websites be doing? Do ...
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5answers
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openssl: recover key and IV by passphrase

A large amount of files were encrypted by openssl enc -aes-256-cbc -pass pass:MYPASSWORD Openssl should derive key+IV from passphrase. I'd like to know key+IV equivalent of that MYPASSWORD. Is ...
225
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1answer
89k views

How exactly does the OpenSSL TLS heartbeat (Heartbleed) exploit work?

I've been hearing more about the OpenSSL Heartbleed attack, which exploits some flaw in the heartbeat step of TLS. If you haven't heard of it, it allows people to: Steal OpenSSL private keys Steal ...
207
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15answers
304k views

Provide subjectAltName to openssl directly on the command line

Is it possible to provide a subjectAltName-Extension to the openssl req module directly on the command line? I know it's possible via a openssl.cnf file, but that's not really elegant for batch-...
18
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4answers
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Missing X509 extensions with an openssl-generated certificate

My goal is to create a certificate with opensslsimilar to this one generated with cfssl Certificate: Data: Version: 3 (0x2) Serial Number: 60:44:dc:0d:80:f4:54:55:e8:...
113
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5answers
56k views

What should a website operator do about the Heartbleed OpenSSL exploit?

CVE-2014-0160 http://heartbleed.com This is supposed to be a canonical question on dealing with the Heartbeat exploit. I run an Apache web server with OpenSSL, as well as a few other utilities ...
258
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11answers
38k views

How to explain Heartbleed without technical terms?

Most of my friends who are not experienced in computers want to know what Heartbleed is and how it works. How would one explain Heartbleed to someone without a technical background?
59
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4answers
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Does Heartbleed mean new certificates for every SSL server?

If you haven't heard of the Heartbleed Bug, it's something to take a look at immediately. It essentially means that an attacker can exploit a vulnerability in many versions of OpenSSL to be able to ...
24
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2answers
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Extract pre-master keys from an OpenSSL application

Consider an application using OpenSSL which has a bug. A packet capture of the full SSL session is available, as well as a core dump and debugging symbols for the application and libraries. A RSA ...
61
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2answers
23k views

Does the heartbleed vulnerability affect clients as severely?

If I have a web crawler (using a non-patched version of OpenSSL) that can be coaxed to connect to an evil https-site, can they get everything from my process memory? To attack a server you can keep ...
28
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1answer
36k views

SSL certificates and cipher suites correspondence

I have been learning about the SSL/TLS protocol (from https://tools.ietf.org/html/rfc5246) and have a few conceptual questions about the protocol. The client and server exchange "hello" messages ...
13
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1answer
6k views

Is openssl aes-256-cbc encryption safe for offsite backup

I have around 20000 files (around 9GB) each of which is encrypted using openssl enc -aes-256-cbc -in infile -out outfile -k mypassword command. Each file uses same password. My openssl version is 1.1....
11
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3answers
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Use openssl to individually verify components of a certificate chain

This is related to another question, How to verify a signature of one entity by another using OpenSSL CLI? I used openssl s_client -showcerts -connect www.google.com:443 to collect three certificates ...
5
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1answer
794 views

Can OpenSSL decrypt the encrypted signature in an Amazon Alexa request to a web service?

OpenSSL newbie here. We're using OpenSSL to parse and verify the certificate and signature that Amazon's Alexa sends to external web services, following their list of requirements in the instructions ...
36
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4answers
29k views

Can someone explain 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); ...
20
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5answers
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How can I verify that SSLv3 protocol is disabled?

I'm trying to disable SSLv3 in ejabberd 2.1.10 on Ubuntu 12.04. There is no way to disable it in config file, so I have to patch the source and rebuild the package: https://github.com/processone/...
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6answers
204k views

Converting keys between openssl and openssh

If I use the following openssl req -x509 -days 365 -newkey rsa:2048 -keyout private.pem -out public.pem -nodes I get private.pem and public.pem If I use ssh-keygen -t rsa -f rsa I get rsa and ...
31
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2answers
16k views

stronger encryption for SSH keys

I configured my server to encrypt user passwords using 500,000 rounds of SHA-512. The question is, how does the standard AES-128-CBC encrypted SSH private key stack up to that, provided the same (or ...
91
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2answers
122k views

How do I get the RSA bit length with the pubkey and openssl?

I have a public key generated with ssh-keygen and I'm just wondering how I get information on the keylength with openssl?
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5answers
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Creating my own CA for an intranet

I need to create my own CA for an intranet and unfortunately it seems there's no good answer about this on Security.SE. There are many resources online about this, but all of them are different and ...
67
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3answers
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Heartbleed: Why does the client supply the length of the message at all?

"The fix for this bug is simple: check that the length of the message actually matches the length of the incoming request." Why do we even have the client report the length at all? If we can know ...
27
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2answers
24k views

What is the difference between Diffie Hellman generator 2 and 5?

Generating Diffie Hellman parameters in OpenSSL can be done as follows: $ openssl dhparam -out dh2048.pem 2048 Generating DH parameters, 2048 bit long safe prime, generator 2 This is going to take a ...
21
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2answers
7k views

Can Heartbleed be used to obtain memory from other processes?

According to http://heartbleed.com/, memory contents can be leaked from the server to the client and vice versa. Say that I have been banking in a separate browser profile (but under the same user). ...
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2answers
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Can a SSL Certificate dictate protocol?

I know you can set the protocol/cipher via your web server: Nginx: ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_ciphers HIGH:!aNULL:!MD5; Apache: SSLProtocol all -SSLv2 SSLCipherSuite ...
161
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2answers
23k views

What is DROWN and how does it work?

There is a new recent attack "on TLS" named "DROWN". I understand that it appears to use bad SSLv2 requests to recover static (certificate) keys. My question is: How? How can you recover static ...
43
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3answers
20k views

Determine if private key belongs to certificate?

Given a certificate¹ and a private key file², how can I determine if the public key on the certificate matches the private key? My initial thought was to simply encrypt some text with the public key ...
20
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2answers
49k views

OpenSSL generate different types of self signed certificate

Does anyone know how to use OpenSSL to generate certificates for the following public key types: DSA - For DHE_DSS key exchange. Diffie-Hellman - For DH_DSS and DH_RSA key exchange. ECDH - For ...
28
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6answers
18k views

Heartbleed and Routers/ASAs/other

OK, so I first heard about heartbleed a few hours ago through the stack exchange questions feed, and after a moments panic, realised that the only web servers I have secured via OpenSSL are on the ...
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2answers
25k views

How can you check if a private key and certificate match in OpenSSL with ECDSA?

I know how to do this with RSA keys (see this article: Determine if private key belongs to certificate?) however I do not know how to do this for ECDSA certificate / key pairs. With RSA keys, the ...
31
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3answers
53k views

Generate CSR from existing certificate

Can we generate the CSR (certificate signing request) used for certificate signing from the signed certificate? It should work with the original private key when signed again with different authority.
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2answers
6k views

openssl enc uses md5 to hash the password and the salt

Wikipedia states that md5's collision resistance is 2^18 (https://en.wikipedia.org/wiki/MD5). I just found out that openssl enc uses md5 to hash the password and the salt. Let's assume that I want ...
7
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1answer
5k views

Do I put my subordinate (intermediate) or root CA certificate in my truststore?

I have a server using a certificate signed by my subordinate (intermediate) CA. My java based client needs to put either the intermediate or root CA cert in it's truststore so when it communicates ...
13
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4answers
62k views

Using the openssl command, how can I tell if it's using TLS 1.0?

Due to a security scan, I was told to not use TLS1.0. I found a link that gave me commands to use to check if a specific protocol is used/enabled. The command I ran (with output is) (Output from TLS1....
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2answers
14k views

Subject Alternative Name in Certificate Signing Request apparently does not survive signing

So I have been able to create a Certificate Signing Request with a Subject Alternative Name of the form subjectAltName=IP:1.2.3.4 by following the recipe in a previous (splendid) answer. When I ...
3
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4answers
3k views

Trust a non-root CA in OpenSSL

Is it possible to have OpenSSL trust a non-root CA such that a certificate signed by that non-root CA can be properly verified? I've noticed that the default behavior for OpenSSL is to only verify ...
7
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3answers
7k views

File security when encrypting files directly with the openssl command / and what about SHA1 hashing password first?

I've been using this command to encrypt files for a while now: openssl aes-256-cbc -a -salt -in secrets.txt -out secrets.txt.enc Then I type in a password. Can someone tell me, roughly speaking, ...
3
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2answers
5k views

Can't request ocsp status with chain of certificates

I have deployed basic ocsp server from OpenSSl Cookbook by Ivan Ristic page 44 with following command $ openssl ocsp -port 9080 -index db/index -rsigner root-ocsp.crt -rkey private/root-ocsp.key -CA ...
6
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2answers
3k views

WPA2 Enterprise EAP-TLS Key Exchange

I'm in the process of implementing 802.1x WPA2 Enterprise Authentication using FreeRadius and EAP-TLS (Mutual TLS Cert Based Auth). I am keen to understand how to actual protocols work together and ...
5
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3answers
3k views

Is it possible to modify a CA without having to reissue all of the derived certificates?

Background: I have my own authoritative certificate that I generated myself for signing certificates for services my friends and I use, including web server, ircd, etc. It's convenient because I don'...
2
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1answer
5k views

Why is this version of OpenSSL (1.0.1e) not vulnerable to Heartbleed?

I recently ran into a requirement that needed a web server set up with SSL, to show that its possible to extract the private key from a server with a vulnerable version of OpenSSL (Heartbleed). Hence, ...
1
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1answer
2k views

decrypt a soap message using openssl

I've tried to do the same as found in How to you manually decrypt a SOAP message using openssl? Unfortunatly without success... Here is my situation : I'm trying to do the same stuff only my data ...
0
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1answer
78 views

Can you use Https to prove document was sent from domain?

I'm aware that you can use tools like GPG to both encrypt and sign information. However HTTPS seems to only be used for encryption. The browser shows me the connection is secure, but there is no way ...
0
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1answer
510 views

Generate X509 ERR_CERT_COMMON_NAME_INVALID

I am trying to set up https server on python3, but I could not generate a certificate and a key properly. That is the server code: import http.server, ssl server_address = ('localhost', 4443) httpd =...
0
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2answers
166 views

Different certificates for the same website?

When I load https://objective-see.com in Safari, it shows me a certificate with CN=objective-see.com. However, when I retrieve the certificate using echo -e | openssl s_client -connect "objective-see....
125
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5answers
558k views

How do I use “openssl s_client” to test for (absence of) SSLv3 support?

In order to mitigate the "Poodle" vulnerability, I'd like to disable SSLv3 support in my (in this case, TLS, rather than HTTPS) server. How can I use openssl s_client to verify that I've done this?
106
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3answers
74k views

Which elliptic curve should I use?

I am currently renewing an SSL certificate, and I was considering switching to elliptic curves. Per Bernstein and Lange, I know that some curves should not be used but I'm having difficulties ...
36
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1answer
8k views

How does OpenSSL generate a big prime number so fast?

In order to generate a 2048 bit RSA key pair, you need to generate two big prime numbers with 1024 bits length. As far as I know, OpenSSL chooses a random 1024 bit number and starts looking for a ...
13
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2answers
12k views

OpenSSL PKCS#7 vs. S/MIME

OpenSSL 1.0.1c onwards seems to offer CMS support. I have difficulty understanding the difference between smime and pkcs7. S/MIME specs are layered on PKCS#7 (so says Wikipedia). Now in openssl I ...