RHSA-2010:0838: Moderate: pki security and enhancement update

Red Hat Certificate System is an enterprise software system designed tomanage enterprise public key infrastructure (PKI) deployments. SimpleCertificate Enrollment Protocol (SCEP) is a PKI communication protocolused to automatically enroll certificates for network devices.The certificate authority allowed unauthenticated users to request theone-time PIN in an SCEP request to be decrypted. An attacker able to sniffan SCEP request from a network device could request the certificateauthority to decrypt the request, allowing them to obtain the one-timePIN. With this update, the certificate authority only handles decryptionrequests from authenticated registration authorities. (CVE-2010-3868)The certificate authority allowed the one-time PIN used in SCEP requeststo be re-used. An attacker possessing a valid SCEP enrollment one-time PINcould use it to generate an unlimited number of certificates.(CVE-2010-3869)The certificate authority used the MD5 hash algorithm to sign all SCEPprotocol responses. As MD5 is not collision resistant, an attacker coulduse this flaw to perform an MD5 chosen-prefix collision attack to generateattack-chosen output signed using the certificate authority's key.(CVE-2004-2761)This update also adds the following enhancements: New configuration options for the SCEP server can define the default and allowed encryption and hash algorithms. These options allow disabling usesof the weaker algorithms not required by network devices and preventpossible downgrade attacks. These can be configured by adding the followingoptions 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 SCEPcommunication too. A designated SCEP key pair can be referenced by addinga new option, ca.scep.nickname=[scep certificate nickname], to thecertificate 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 configurationfile. The limit is set to 16 bytes in the default CS.cfg configurationfile.All users of Red Hat Certificate System 8 should upgrade to these updatedpackages, which resolve these issues and add these enhancements.