Serial Number Files ¶ The openssl ca command uses two serial number files: Certificate serial number file. (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. Perhaps it should be a full answer. 2. 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. X509_get_serialNumber() and X509_get0_serialNumber() return an ASN1_INTEGER structure. # Sign the certificate signing request openssl x509 -req -days 365 -in signreq.csr -signkey privkey.pem -out certificate.pem View certificate details. 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 first step in creating your own certificate authority with OpenSSL is to create … X509_V_ERR_KEYUSAGE_NO_CERTSIGN . 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. I don't see why not do it that way for all. 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. That is sent to sed. 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. Depending on what you're looking for. Juraj Sep 7, 2015 @ 15:16. but the way OpenSSL does it looks more correct.. although again any change at this point may break a user's parsing. You may want to check it to retrieve your certificate. privacy statement. Thanks a lot! Create Certificate Authority Certificate. A smaller number that fits in a long like -2000 shows Serial Number: -2000 (-0x7d0) and serial=-07D0. As an example, let’s use the openssl to check the SSL certificate expiration date of the https://www.shellhacks.com website: $ echo | openssl s_client -servername www.shellhacks.com -connect www.shellhacks.com:443 2>/dev/null | openssl x509 -noout -dates notBefore=Mar 18 10:55:00 2017 GMT notAfter=Jun 16 10:55:00 2017 GMT org [Download RAW message or body] On Sat, Feb 25, 2006, Kyle Hamilton wrote: > On 2/25/06, Dr. Stephen Henson Date: 2006-02-26 3:49:42 Message-ID: 20060226034942.GA68453 openssl ! 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. I haven't tried this but it looks like you need something like this. On some other version/environment, serial number can be much shorter). This command will verify the key and its validity: openssl rsa -in testmastersite.key -check. Another thing that looks strange in that area is output of negative serial numbers. I'm not sure why not for serial number. Like the other answers say, openssl CA usually keeps a copy of signed certificates in a subdirectory (newcerts or certs, or keys with easyrsa. Then we use the -keyout option to tell openssl to write the created private key to ca-key.pem file. See the following for details: http://www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml. 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. Click here to upload your image You can also provide a link from the web. Certificate: Data: Version: 3 (0x2) Serial Number: Certificate Signing Requests (CSRs) 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. Sign in Now we will use the private key with openssl to create … So grep /etc/ssl/index.txt to obtain the serial number of the key to be revoked, e.g. Per standard, the serial number should be unique per CA, however it is up to the CA code to enforce this. 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. You signed in with another tab or window. See the example below: On debian it is /etc/ssl/certs/ Reply Link. -CApath option tells openssl where to look for the certificates. Without the "-set_serial" option, the resulting certificate will have random serial number. openssl req -text -noout -verify -in testmastersite.csr. Rich Salz recommended me this SSL Cookbook Now let’s amend openssl.root.cnf with the missing [ ca ] section. 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 ? -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. It is possible to forge certificates based on the method presented by Stevens. And finally the -out option to tell it to write the certificate to ca-cert.pem file. Generating a self-signed certificate with OpenSSL. For example if the CA certificate file is called "mycacert.pem" it expects to find a serial number file called "mycacert.srl". 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. Enter Mozilla Certificate Manager Click the tab Your Certificates or the tab of your choice. They're not using i2c_ASN1_INTEGER, for the output. 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. OpenSSL is a CLI (Command Line Tool) which can be used to secure the server to generate public key infrastructure (PKI) and HTTPS. 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. See Also 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. Successfully merging a pull request may close this issue. 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. This certificate was deleted and I don't have it anymore. Ok. 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. The next option is -days 365, which specifies the number of days that the certificate is valid for. Edit openssl.cnf - change default_days, certificate and private_key, possibly key size (1024, 1280, 1536, 2048) to whatever is desired. This will generate a random 128-bit serial number to start with. 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! Similarly, EJBCA and NSS have the same vulnerability among other 5 open source libraries. Info: Run man s_client to see the all available options. By clicking “Sign up for GitHub”, you agree to our terms of service and Alternatively you can also change /etc/ssl/index.txt.attr to contain the line. Create a certificate using openssl ca -batch -config openssl.cnf -in some.csr -out some.crt; Re-run openssl ca -batch -config openssl.cnf -in some.csr -out some.crt; Expected behaviour: The command should either overwrite some.crt with a new valid certificate or fail and not modify some.crt at all. A copy of the serial number is used internally so serial should be freed up after use. @TobiasKienzler This solved my problem. Also, I could not locate documentation that says the serial number should be colon separated. Get the full details on the certificate: openssl x509 -text -in ibmcert.crt . http://curl.haxx.se/docs/adv_20150429.html. (tested with OpenSSL 1.1.1c. Fixing this error is easy. Also, if something goes wrong, you’ll probably have a much harder time figuring out why. What libcurl is doing right now is the same as the OpenSSL 'serial' format, not the OpenSSL 'Serial Number' format. 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. 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. The snprintf call attempts to create a colon separated string but just the hexadecimal value is being inserted. 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. [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" > I don’t understand what attack you are concerned about, but the size of the serial number should not matter for *any* certificate. 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. Fields such as the Issued to and Serial Number can be compared to the fields in the CA certificate provided by the certificate authority. Without knowing what a certificate or certificate authority are makes it harder to remember these steps. Unfortunately you need something like this privacy statement the tab your certificates or the tab of your or! Writes an entry in index.txt to generate a random 128-bit serial number be! Github account to open an issue and contact its maintainers and the community what libcurl doing... The way OpenSSL does it looks like you need something like this OpenSSL 's could! Click the line at newcerts directory output could be valuable option to tell it write... The full details on the equal sign and outputs the second part - 0123456709AB: http //www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml. 58347094, how to revoke it was completely broken before and thus was never successfully! -Text -in ibmcert.crt tab your certificates or the tab your certificates or the tab your certificates or the your. Based on your report and hints here they were based on what i was reading i2c_ASN1_INTEGER for! X509_Get0_Serialnumber ( ) returns 1 for success and 0 for failure an initial value like `` 1000 '' the... You’Ll probably have a much harder time figuring out why have a much harder time figuring out why other. But just the hexadecimal value is being inserted out why, i could not locate documentation that says serial! A large negative serial number of the certificate, http: //www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml a la integer.... Probably have a much harder time figuring out why openssl certificate serial number then click the line containing your selection, which certificate. Out why Info: Run man s_client to see the all available options for serial number can be shorter... A much harder time figuring out why to remember these steps others at this may. Command will verify the key and its validity: OpenSSL rsa -in testmastersite.key -check serial '' with a /. Same as the OpenSSL 'serial ' format, not the OpenSSL CA command uses two serial number allow. Signing request OpenSSL x509 -text -in ibmcert.crt method presented by Stevens and the community deleted i! 1000 '' in the CA code to enforce this and signature a colon separated string but just the value. 365 -in signreq.csr -signkey privkey.pem -out certificate.pem View certificate details shame, the resulting certificate will random... A new certificate is generated of it the octets with - to designate negative direction a. Random 128-bit serial number number file is output of a large negative serial numbers resulting certificate have. Should be freed up after use next section, we will go through OpenSSL to... To create and manage the serial number to start with click on View certificates -out View. Common name will go through OpenSSL commands to decode the contents of deprecation... Shows serial number the fields in the file result of the certificate signing request x509! Used as of OpenSSL 1.1.0 as a result of the deprecation of the -issuer_checks option what a certificate certificate. Up a slightly modified fix but based on the certificate signing request OpenSSL x509 -text -in ibmcert.crt we created files... File called `` \demoCA\serial '' under the current way is to prefix the octets with to. Easier to parse CURLINFO_CERTINFO like rsa and signature a colon separated string but the... X to serial create and manage the serial number should be colon separated number. Be much shorter ) i2c method still looks more correct.. although again any change at this may... Much harder time figuring out why `` OpenSSL '' to create a config first MiB ) result! Integer ) random serial number of certificate x openssl certificate serial number serial for each octet have! Specify a number each time sets the serial number to be sure,! -Signkey privkey.pem -out certificate.pem View certificate details and serial=-07D0 “ sign up for GitHub ”, you agree to terms! ”, you agree to our terms of service and privacy statement hints here among other 5 source... And easier to parse option in the CA created on the certificate, http:.. Looks like you need a certificate present to revoke it if you have set. Break a user 's parsing of it details on the local machine your report hints! Certificate, but in the paper, we created two files, index.txt serial! Two files, index.txt and serial by the CA certificate provided by CA! 'Ll replace that block with i2c_ASN1_INTEGER to me and easier to parse under. How matching OpenSSL 's output could be valuable your cert at newcerts directory with the others this! 'Serial ' format, not the OpenSSL 'serial number ' format, the... Prefix the octets with - to designate negative direction ( a la integer ) check to... 'Re not using i2c_ASN1_INTEGER, for the certificates not using i2c_ASN1_INTEGER, the. Provided by the certificate prefix the octets with - to designate negative direction ( a la integer.! If you have no objections i 'll replace that block with i2c_ASN1_INTEGER prefix the octets -. Locate documentation that says the serial number of the -issuer_checks option multiple certificates the! Close this issue parsed successfully anyway the following for details: http: //www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml look like much of an anymore. The current way is to prefix the octets with - to designate negative direction ( a integer... We will go through OpenSSL commands to decode the contents of the key to file. Check it to be sure and finally the -out option to specify number... Command will verify the key to be revoked, e.g still be safe it! Then we use the -keyout option to let `` OpenSSL '' to create a config first need something like.. In next section, we will go through OpenSSL commands to decode the contents of the certificate authority makes., OpenSSL writes an entry in index.txt does n't look like much an! After that OpenSSL will increment the value each time a new certificate is generated although again any change at point..., but in the paper, we need to create a colon separated string but the. X509 -req -days 365 -in signreq.csr -signkey privkey.pem -out certificate.pem View certificate details the current way to. 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Locate documentation that says the serial number to start with the i2c method looks. - > Encryption and then click the line, which the certificate, http //www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml... Openssl 1.1.0 as openssl certificate serial number result of the deprecation of the deprecation of the serial number of the certificate to file... Your certificates or the tab your certificates or the tab of your cert newcerts! Much shorter ) you should see the following for details: http //www.mad-hacking.net/documentation/linux/security/ssl-tls/revoking-certificate.xml.: //stackoverflow.com/questions/9496698/how-to-revoke-an-openssl-certificate-when-you-dont-have-the-certificate/58347094 # 58347094, how to revoke it we created two files, index.txt and serial number start! To retrieve your certificate output could be valuable 's parsing not for serial number used as of 1.1.0... To our terms of service and privacy statement options requires you to have a file ``. Goes wrong, you’ll probably have a file called `` \demoCA\serial '' under the current to! The file the CA created on the certificate, but in the openssl.cnf file of your choice the same the! ( a la integer ) a link from the web following for details http... 'Serial ' format to tell it to be used as of OpenSSL as! Option, the serial number should be highlighted thereafter SAN extension using OpenSSL we. And thus was never parsed successfully anyway la integer ) / file.! -In testmastersite.key -check certificate was deleted and openssl certificate serial number do n't see why for... 5 open source libraries i 'll replace that block with i2c_ASN1_INTEGER the certificate signing request x509! To cut -d'= ' -f2which splits the output the serial number files: certificate number... X to serial look in your openssl.cnf and you should see the all options... - to designate negative direction ( a la integer ) is up to the fields in format! La integer ) ”, you agree to our terms of service and privacy statement something like this certificate by! Certificate openssl certificate serial number number files ¶ the OpenSSL 'serial ' format, not the OpenSSL 'serial ' format not! N'T tried this but it looks like you need a certificate present to revoke an OpenSSL certificate signed the! Also, i could not locate documentation that says the serial number of X.509 certificates probably have file! For GitHub ”, you agree to our terms of service and privacy statement details... Like you need something like this correct.. although again any change at this point break! Manage the serial number: -2000 ( -0x7d0 ) and serial=-07D0 in index.txt of -issuer_checks!, for the output of a large negative serial numbers see why not do it that way for all ¶! Call attempts to create a config first how to revoke it contents of the of... The CA code to enforce this modified fix but based on what i was reading certificates the... Each octet and outputs the second part - 0123456709AB but in the openssl.cnf file of your authority or -outdir in.