Updated rhpki-ca, rhpki-common, and rhpki-util packages that fix three security issues and add several enhancements are now available for Red Hat Certificate System 7.3. The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.
Red Hat Certificate System is an enterprise software system designed to manage enterprise public key infrastructure (PKI) deployments. Simple Certificate Enrollment Protocol (SCEP) is a PKI communication protocol used to automatically enroll certificates for network devices. The certificate authority allowed unauthenticated users to request the one-time PIN in an SCEP request to be decrypted. An attacker able to sniff an SCEP request from a network device could request the certificate authority to decrypt the request, allowing them to obtain the one-time PIN. With this update, the certificate authority only handles decryption requests from authenticated registration authorities. (CVE-2010-3868) The certificate authority allowed the one-time PIN used in SCEP requests to be re-used. An attacker possessing a valid SCEP enrollment one-time PIN could use it to generate an unlimited number of certificates. (CVE-2010-3869) The certificate authority used the MD5 hash algorithm to sign all SCEP protocol responses. As MD5 is not collision resistant, an attacker could use this flaw to perform an MD5 chosen-prefix collision attack to generate attack-chosen output signed using the certificate authority's key. (CVE-2004-2761) This update also adds the following enhancements: * Support for the stronger encryption algorithm Triple-DES (DES3), and stronger hash algorithms SHA1, SHA256, and SHA512, for use in SCEP communication. These algorithms are in addition to the previously supported DES and MD5 algorithms. * New configuration options for the SCEP server can define the default and allowed encryption and hash algorithms. These options allow disabling uses of the weaker algorithms not required by network devices and prevent possible downgrade attacks. These can be configured by adding the following options to the certificate authority's CS.cfg configuration file: ca.scep.encryptionAlgorithm=DES3 ca.scep.allowedEncryptionAlgorithms=DES3 ca.scep.hashAlgorithm=SHA1 ca.scep.allowedHashAlgorithms=SHA1,SHA256,SHA512 * With this update, the certificate authority's SCEP server is disabled by default. The SCEP server can be enabled by adding the 'ca.scep.enable=true' option to the certificate authority's CS.cfg configuration file. * A separate key pair can now be configured for use in SCEP communication. Previously, the main certificate authority's key pair was used for SCEP communication too. A designated SCEP key pair can be referenced by adding a new option, ca.scep.nickname=[scep certificate nickname], to the certificate authority's CS.cfg configuration file. * The certificate authority now allows the size of nonces used in SCEP requests to be restricted by adding a new option, ca.scep.nonceSizeLimit= [number of bytes], to the certificate authority's CS.cfg configuration file. The limit is set to 16 bytes in the default CS.cfg configuration file. All users of Red Hat Certificate System 7.3 should upgrade to these updated packages, which resolve these issues and add these enhancements.