Certificate Authority Functions¶ When setting up a new CA on a system, make sure index.txt and serial exist (empty and set to 01, respectively), and create directories private and newcert. Certificate Signing Requests (CSRs) On 08/21/2017 09:20 AM, Salz, Rich via openssl-users wrote: > But in doing this, I can't figure out if there is a risk on serial > number size for a root CA cert as there is for any other cert. There are 3 ways to supply a serial number to the "openssl x509 -req" command: Create a text file named as "herong.srl" and put a number in the file. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy, 2021 Stack Exchange, Inc. user contributions under cc by-sa, https://stackoverflow.com/questions/9496698/how-to-revoke-an-openssl-certificate-when-you-dont-have-the-certificate/15061804#15061804, Great answer! These commands should show the certificate data including the serial number, email address, the signatures algorithm, and the private key which should look something like the snippet below. Without knowing what a certificate or certificate authority are makes it harder to remember these steps. Enter Mozilla Certificate Manager Click the tab Your Certificates or the tab of your choice. A copy of the serial number is used internally so serial should be freed up after use. Click here to upload your image This will generate a random 128-bit serial number to start with. https://stackoverflow.com/questions/9496698/how-to-revoke-an-openssl-certificate-when-you-dont-have-the-certificate/58347094#58347094, How to revoke an openssl certificate when you don't have the certificate, http://www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml. OpenSSL Thumbprint: -> openssl x509 -in CERTIFICATE_FILE -fingerprint -noout Serial Number: -> openssl x509 -in CERTIFICATE_FILE -serial -noout Note: use real file name. You may want to check it to retrieve your certificate. See Also Similarly, EJBCA and NSS have the same vulnerability among other 5 open source libraries. libcurl had something similar to that for small numbers prior to your change but it would have to be modified to take into account negative numbers. # Sign the certificate signing request openssl x509 -req -days 365 -in signreq.csr -signkey privkey.pem -out certificate.pem View certificate details. http://curl.haxx.se/docs/adv_20150429.html. Also, I could not locate documentation that says the serial number should be colon separated. I haven't tried this but it looks like you need something like this. Per standard, the serial number should be unique per CA, however it is up to the CA code to enforce this. Already on GitHub? It is therefore piped to cut -d'=' -f2which splits the output on the equal sign and outputs the second part - 0123456709AB. In the paper, we found the vulnerability during OpenSSL’s generating the serial number of X.509 certificates. Many HOW-TOs will have you echo "01" into the serial file thus starting the serial number at 1, and using 8-bit serial numbers instead of 128-bit serial numbers. Have a question about this project? These options requires you to have a file called "\demoCA\serial" under the current directory to be used as a serial number register. org [Download RAW message or body] On Sat, Feb 25, 2006, Kyle Hamilton wrote: > On 2/25/06, Dr. Stephen Henson Encryption and then click on View Certificates. Not used as of OpenSSL 1.1.0 as a result of the deprecation of the -issuer_checks option. Shame, the i2c method still looks more correct to me and easier to parse! Data: Version: 3 (0x2) Serial Number: xxxxxxxxxxxxxxxx Signature Algorithm: sha1WithRSAEncryption Issuer: CN=My organisation RootCA Validity Not Before: May 20 13:11:34 2016 GMT Not After : May 20 13:21:34 2021 GMT Subject: DC=org, DC=example, CN=My organisation Issuing CA X509_get_serialNumber() and X509_get0_serialNumber() return an ASN1_INTEGER structure. Also, if something goes wrong, you’ll probably have a much harder time figuring out why. Not used as of OpenSSL 1.1.0 as a result of the deprecation of the -issuer_checks option. X509_V_ERR_KEYUSAGE_NO_CERTSIGN . OpenSSL in their output uses the colon as a separator but only for long serial numbers (see openssl x509 -noout -text -in cert). I made an openssl certificate signed by the CA created on the local machine. Fixing this error is easy. You have to set an initial value like "1000" in the file. -create_serial is especially important. Generating a self-signed certificate with OpenSSL. I should've tested the output of a large negative serial number to be sure. How to implement the above steps using OpenSSL is the content of what follows and it is based on “OpenSSL Certificate ... certificates and serial ... certificate database and serial number. Though changing it to be consistent with the others at this point may break a user's parsing of it. Alternatively you can also change /etc/ssl/index.txt.attr to contain the line. To view the details of a certificate and verify the information, you can use the following command: # Review a certificate openssl x509 -text -noout -in certificate… That is sent to sed. I'm not sure why not for serial number. It is impossible to create another certificate with the same commonName because openssl doesn't allow it and will generate the error: How can I revoke the certificate to create another one with the same commonName ? Use the "-set_serial n" option to specify a number each time. If the chosen-prefix collision of so… but the way OpenSSL does it looks more correct.. although again any change at this point may break a user's parsing. We will also add a section to the config file named [ v3_intermediate_ca ] that we will later use whenever we want to sign an intermediate certificate using our root CA. Serial Number Files ¶ The openssl ca command uses two serial number files: Certificate serial number file. I don't see why not do it that way for all. @jay changing it could still be safe as it was completely broken before and thus was never parsed successfully anyway! X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH . 1013, then execute the following command: The -keyfile and -cert mentioned in Nilesh's answer are only required if that deviates from your openssl.cnf settings. Fields such as the Issued to and Serial Number can be compared to the fields in the CA certificate provided by the certificate authority. @TobiasKienzler This solved my problem. Get the full details on the certificate: openssl x509 -text -in ibmcert.crt . This command will verify the key and its validity: openssl rsa -in testmastersite.key -check. Take a look in your openssl.cnf and you should see the option "serial" with a path / file specified. To generate a ce r tificate with SAN extension using OpenSSL, we need to create a config first. What libcurl is doing right now is the same as the OpenSSL 'serial' format, not the OpenSSL 'Serial Number' format. Certificate: Data: Version: 3 (0x2) Serial Number: (Based on Nilesh's answer) In the default configuration, openssl will keep copies of all signed certificates in /etc/ssl/newcerts, named by its index number. The openssl ca -config openssl.cnf -gencrl -crldays 30 -out crl.pem will be the actual step to revoke the certificate, producing a signed list using the private key of the authority. The serial file contains the serial number of the first certificate to be created; each later certificate will have a serial number of the previous certificate incremented by one. to allow multiple certificates with the same common name. That's probably fine given that nobody's used it yet, but if you want I can change it to their 'Serial Number' format as seen in X509_print_ex. Landed in aff153f. Now we will use the private key with openssl to create … Serial Number: 14 (0xe) Signature Algorithm: sha256WithRSAEncryption Issuer: CN=I-CA Validity Not Before: Nov 29 14:20:54 2018 GMT Not After : Nov 29 14:20:54 2020 GMT Subject: CN=test.domain.net Subject Public Key Info: Certificate: Data: Version: 3 (0x2) Serial Number: 15 (0xA) Signature Algorithm: sha256WithRSAEncryption To get long serial numbers returned from the library I changed the above block to: The text was updated successfully, but these errors were encountered: Thanks! The first step in creating your own certificate authority with OpenSSL is to create … Don't miss-interpret it as a normal integer datatype, OpenSSL uses the special ASN1_INTEGER data type which is not really a 'number' but rather a array of bytes. It is possible to forge certificates based on the method presented by Stevens. Return Values. This certificate was deleted and I don't have it anymore. Depending on what you're looking for. A smaller number that fits in a long like -2000 shows Serial Number: -2000 (-0x7d0) and serial=-07D0. In next section, we will go through OpenSSL commands to decode the contents of the Certificate. openssl automatically saves a copy of your cert at newcerts directory. You signed in with another tab or window. Create CA Certificate: org> Date: 2006-02-26 3:49:42 Message-ID: 20060226034942.GA68453 openssl ! Although MD5 has been replaced by CAs now, with the development of technology, new attacks for current hash algorithm adopted by CAs, such as SHA-256, will probably occur in the future. If you have no objections I'll replace that block with i2c_ASN1_INTEGER. So grep /etc/ssl/index.txt to obtain the serial number of the key to be revoked, e.g. 2. openssl req -text -noout -verify -in testmastersite.csr. Sign in Not used as of OpenSSL 1.1.0 as a result of the deprecation of the -issuer_checks option. See the following for details: http://www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml. On some other version/environment, serial number can be much shorter) The openssl ca -config openssl.cnf -gencrl -crldays 30 -out crl.pem will be the actual step to revoke the certificate, producing a signed list using the private key of the authority. Info: Run man s_client to see the all available options. Create Certificate Authority Certificate. Similar to the [ req ] section, the [ ca ] section defines default parameter values for the openssl ca command— the interface to OpenSSL’s minimal CA service. After that OpenSSL will increment the value each time a new certificate is generated. Another thing that looks strange in that area is output of negative serial numbers. By clicking “Sign up for GitHub”, you agree to our terms of service and The serial number is taken from that file. The current way is to prefix the octets with - to designate negative direction (a la integer). Click Serial number or Thumbprint. This is the certificate that we want to decode (Part of the certificate displayed below is erased due to security concerns). X509_set_serialNumber() sets the serial number of certificate x to serial. X509_set_serialNumber() returns 1 for success and 0 for failure. For other octets retrieved via CURLINFO_CERTINFO like rsa and signature a colon is used as the separator for each octet. (max 2 MiB). In lib/vtls/openssl/c in version 7.41.0 at line 2466 we have: Since bufp gets pushed to return a certificate serial number setting the first character to null will always cause null to be returned, therefore, line 2477 should be removed. [prev in list] [next in list] [prev in thread] [next in thread] List: openssl-users Subject: Re: openssl req -x509 does not create serial-number 0 From: "Dr. Stephen Henson" /dev/null | openssl x509 -noout -dates notBefore=Mar 18 10:55:00 2017 GMT notAfter=Jun 16 10:55:00 2017 GMT -CAcreateserial with this option the CA serial number file is created if it does not exist: it will contain the serial number "02" and the certificate being signed will have the 1 as its serial number. If the file doesn't exists or is empty when the very first certificate is created then 01 is used as a serial for it. Without the "-set_serial" option, the resulting certificate will have random serial number. Mistake! If anyone came here looking for help when they screwed up their revocation using OpenVPN's tool (like me), then you can copy the "revoke-full" script and make a change to it. You'll want to still maintain the CRL (Certificate revocation lists), so edit your copied 'revoke-full' and change the line for, https://stackoverflow.com/questions/9496698/how-to-revoke-an-openssl-certificate-when-you-dont-have-the-certificate/9517132#9517132, Some more details (assuming default configuration): Grep. On debian it is /etc/ssl/certs/ Reply Link. See the example below: On some other version/environment, serial number can be much shorter). I can see how matching openssl's output could be valuable. Perhaps it should be a full answer. Like the other answers say, openssl CA usually keeps a copy of signed certificates in a subdirectory (newcerts or certs, or keys with easyrsa. Successfully merging a pull request may close this issue. If you have published the original certificate, revoking the old one is however the preferable solution, even if you don't run an OSCP server or provide CRLs. This article helps you as a quick reference to understand OpenSSL commands which are very useful in common, and for everyday scenarios especially for system administrators. I assumed they were based on what I was reading. OpenSSL is a CLI (Command Line Tool) which can be used to secure the server to generate public key infrastructure (PKI) and HTTPS. A smaller number that fits in a long like -2000 shows Serial Number: -2000 (-0x7d0) and serial=-07D0. To create our own certificate we need a certificate authority to sign it (if you don’t know what this means, I recommend reading Brief(ish) explanation of how https works). They're not using i2c_ASN1_INTEGER, for the output. > > I don’t understand what attack you are concerned about, but the size of the serial number should not matter for *any* certificate. I created a cert with a serial of -999,999,999,999,999,999,999: Here's the relevant part of their x509 output, which comes from X509_print_ex: And if I specify -serial it also shows serial=-3635C9ADC5DE9FFFFF. I also glanced over the negative thing before I ignored it but you're right, we should make sure to output the same serial number that openssl does, even when negative.

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