Managing Kerberos and Other Authentication Services in Oracle® Solaris 11.2

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Updated: August 2014

Security Glossary

Access Control List (ACL)

An access control list (ACL) provides finer-grained file security than traditional UNIX file protection provides. For example, an ACL enables you to allow group read access to a file, while allowing only one member of that group to write to the file.

admin principal

A user principal with a name of the form username/admin (as in jdoe/admin). An admin principal can have more privileges (for example, to change policies) than a regular user principal. See also principal name, user principal.


Advanced Encryption Standard. A symmetric 128-bit block data encryption technique. The U.S. government adopted the Rijndael variant of the algorithm as its encryption standard in October 2000. AES replaces user principal encryption as the government standard.


A cryptographic algorithm. This is an established, recursive computational procedure that encrypts or hashes input.

application server

See network application server.

asynchronous audit event

Asynchronous events are the minority of system events. These events are not associated with any process, so no process is available to be blocked and later woken up. Initial system boot and PROM enter and exit events are examples of asynchronous events.

audit files

Binary audit logs. Audit files are stored separately in an audit file system.

audit policy

The global and per-user settings that determine which audit events are recorded. The global settings that apply to the audit service typically affect which pieces of optional information are included in the audit trail. Two settings, cnt and ahlt, affect the operation of the system when the audit queue fills. For example, audit policy might require that a sequence number be part of every audit record.

audit trail

The collection of all audit files from all hosts.

authenticated rights profile

A rights profile that requires the assigned user or role to type a password before executing an operation from the profile. This behavior is similar to sudo behavior. The length of time that the password is valid is configurable.


The process of verifying the claimed identity of a principal.


Authenticators are passed by clients when requesting tickets (from a KDC) and services (from a server). They contain information that is generated by using a session key known only by the client and server, that can be verified as of recent origin, thus indicating that the transaction is secure. When used with a ticket, an authenticator can be used to authenticate a user principal. An authenticator includes the principal name of the user, the IP address of the user's host, and a time stamp. Unlike a ticket, an authenticator can be used only once, usually when access to a service is requested. An authenticator is encrypted by using the session key for that client and that server.


1. In Kerberos, the process of determining if a principal can use a service, which objects the principal is allowed to access, and the type of access that is allowed for each object.

2. In user rights management, a right that can be assigned to a role or user (or embedded in a rights profile) for performing a class of operations that are otherwise prohibited by security policy. Authorizations are enforced at the user application level, not in the kernel.

basic set

The set of privileges that are assigned to a user's process at login. On an unmodified system, each user's initial inheritable set equals the basic set at login.


A symmetric block cipher algorithm that takes a variable-length key from 32 bits to 448 bits. Its author, Bruce Schneier, claims that Blowfish is optimized for applications where the key does not change often.


Narrowly, a process that makes use of a network service on behalf of a user; for example, an application that uses rlogin. In some cases, a server can itself be a client of some other server or service.

More broadly, a host that a) receives a Kerberos credential, and b) makes use of a service that is provided by a server.

Informally, a principal that makes use of a service.

client principal

(RPCSEC_GSS API) A client (a user or an application) that uses RPCSEC_GSS-secured network services. Client principal names are stored in the form of rpc_gss_principal_t structures.

clock skew

The maximum amount of time that the internal system clocks on all hosts that are participating in the Kerberos authentication system can differ. If the clock skew is exceeded between any of the participating hosts, requests are rejected. Clock skew can be specified in the krb5.conf file.


See privacy.


In the Cryptographic Framework feature of Oracle Solaris, a consumer is a user of the cryptographic services that come from providers. Consumers can be applications, end users, or kernel operations. Kerberos, IKE, and IPsec are examples of consumers. For examples of providers, see provider.


An information package that includes a ticket and a matching session key. Used to authenticate the identity of a principal. See also ticket, session key.

credential cache

A storage space (usually a file) that contains credentials that are received from the KDC.

cryptographic algorithm

See algorithm.


Data Encryption Standard. A symmetric-key encryption method developed in 1975 and standardized by ANSI in 1981 as ANSI X.3.92. DES uses a 56-bit key.

device allocation

Device protection at the user level. Device allocation enforces the exclusive use of a device by one user at a time. Device data is purged before device reuse. Authorizations can be used to limit who is permitted to allocate a device.

device policy

Device protection at the kernel level. Device policy is implemented as two sets of privileges on a device. One set of privileges controls read access to the device. The second set of privileges controls write access to the device. See also policy.

Diffie-Hellman protocol

Also known as public key cryptography. An asymmetric cryptographic key agreement protocol that was developed by Diffie and Hellman in 1976. The protocol enables two users to exchange a secret key over an insecure medium without any prior secrets. Diffie-Hellman is used by Kerberos.


See message digest.


Digital Signature Algorithm. A public key algorithm with a variable key size from 512 to 4096 bits. The U.S. Government standard, DSS, goes up to 1024 bits. DSA relies on SHA1 for input.


Elliptic Curve Digital Signature Algorithm. A public key algorithm that is based on elliptic curve mathematics. An ECDSA key size is significantly smaller than the size of a DSA public key needed to generate a signature of the same length.

effective set

The set of privileges that are currently in effect on a process.


Historically, security flavor and authentication flavor had the same meaning, as a flavor that indicated a type of authentication (AUTH_UNIX, AUTH_DES, AUTH_KERB). RPCSEC_GSS is also a security flavor, even though it provides integrity and privacy services in addition to authentication.

forwardable ticket

A ticket that a client can use to request a ticket on a remote host without requiring the client to go through the full authentication process on that host. For example, if the user david obtains a forwardable ticket while on user jennifer's machine, david can log in to his own machine without being required to get a new ticket (and thus authenticate himself again). See also proxiable ticket.


Fully qualified domain name. For example, (as opposed to simply denver).


The Generic Security Service Application Programming Interface. A network layer that provides support for various modular security services, including the Kerberos service. GSS-API provides for security authentication, integrity, and privacy services. See also authentication, integrity, privacy.


The modification of the default configuration of the operating system to remove security vulnerabilities that are inherent in the host.

hardware provider

In the Cryptographic Framework feature of Oracle Solaris, a device driver and its hardware accelerator. Hardware providers offload expensive cryptographic operations from the computer system, thus freeing CPU resources for other uses. See also provider.


A system that is accessible over a network.

host principal

A particular instance of a service principal in which the principal (signified by the primary name host) is set up to provide a range of network services, such as ftp, rcp, or rlogin. An example of a host principal is host/ See also server principal.

inheritable set

The set of privileges that a process can inherit across a call to exec.

initial ticket

A ticket that is issued directly (that is, not based on an existing ticket-granting ticket). Some services, such as applications that change passwords, might require tickets to be marked initial so as to assure themselves that the client can demonstrate a knowledge of its secret key. This assurance is important because an initial ticket indicates that the client has recently authenticated itself (instead of relying on a ticket-granting ticket, which might existed for a long time).


The second part of a principal name, an instance qualifies the principal's primary. In the case of a service principal, the instance is required. The instance is the host's fully qualified domain name, as in host/ For user principals, an instance is optional. Note, however, that jdoe and jdoe/admin are unique principals. See also primary, principal name, service principal, user principal.


A security service that, in addition to user authentication, provides for the validity of transmitted data through cryptographic checksumming. See also authentication, privacy.

invalid ticket

A postdated ticket that has not yet become usable. An invalid ticket is rejected by an application server until it becomes validated. To be validated, an invalid ticket must be presented to the KDC by the client in a TGS request, with the –VALIDATE flag set, after its start time has passed. See also postdated ticket.


    Key Distribution Center. A machine that has three Kerberos V5 components:

  • Principal and key database

  • Authentication service

  • Ticket-granting service

Each realm has a master KDC and should have one or more slave KDCs.


An authentication service, the protocol that is used by that service, or the code that is used to implement that service.

The Kerberos implementation in Oracle Solaris that is closely based on Kerberos V5 implementation.

While technically different, “Kerberos” and “Kerberos V5” are often used interchangeably in the Kerberos documentation.

Kerberos (also spelled Cerberus) was a fierce, three-headed mastiff who guarded the gates of Hades in Greek mythology.

Kerberos policy

A set of rules that governs password usage in the Kerberos service. Policies can regulate principals' accesses, or ticket parameters, such as lifetime.


    1. Generally, one of two main types of keys:

  • A symmetric key – An encryption key that is identical to the decryption key. Symmetric keys are used to encrypt files.

  • An asymmetric key or public key – A key that is used in public key algorithms, such as Diffie-Hellman or RSA. Public keys include a private key that is known only by one user, a public key that is used by the server or general resource, and a private-public key pair that combines the two. A private key is also called a secret key. The public key is also called a shared key or common key.

2. An entry (principal name) in a keytab file. See also keytab file.

    3. In Kerberos, an encryption key, of which there are three types:

  • A private key – An encryption key that is shared by a principal and the KDC, and distributed outside the bounds of the system. See also private key.

  • A service key – This key serves the same purpose as the private key, but is used by servers and services. See also service key.

  • A session key – A temporary encryption key that is used between two principals, with a lifetime limited to the duration of a single login session. See also session key.


A keystore holds passwords, passphrases, certificates, and other authentication objects for retrieval by applications. A keystore can be specific to a technology, or a location that several applications use.

keytab file

A key table file that contains one or more keys (principals). A host or service uses a keytab file in the much the same way that a user uses a password.


Key version number. A sequence number that tracks a particular key in order of generation. The highest kvno is the latest and most current key.

least privilege

A security model which gives a specified process only a subset of superuser powers. The least privilege model assigns enough privilege to regular users that they can perform personal administrative tasks, such as mount file systems and change the ownership of files. On the other hand, processes run with just those privileges that they need to complete the task, rather than with the full power of superuser, that is, all privileges. Damage due to programming errors like buffer overflows can be contained to a non-root user, which has no access to critical abilities like reading or writing protected system files or halting the machine.

limit set

The outside limit of what privileges are available to a process and its children.

name service scope

The scope in which a role is permitted to operate, that is, an individual host or all hosts that are served by a specified naming service such as NIS LDAP.


1. See message authentication code (MAC).

2. Also called labeling. In government security terminology, MAC is Mandatory Access Control. Labels such as Top Secret and Confidential are examples of MAC. MAC contrasts with DAC, which is Discretionary Access Control. UNIX permissions are an example of DAC.

3. In hardware, the unique system address on a LAN. If the system is on an Ethernet, the MAC is the Ethernet address.

master KDC

The main KDC in each realm, which includes a Kerberos administration server, kadmind, and an authentication and ticket-granting daemon, krb5kdc. Each realm must have at least one master KDC, and can have many duplicate, or slave, KDCs that provide authentication services to clients.


An iterative cryptographic hash function that is used for message authentication, including digital signatures. The function was developed in 1991 by Rivest. Its use is deprecated.


1. A software package that specifies cryptographic techniques to achieve data authentication or confidentiality. Examples: Kerberos V5, Diffie-Hellman public key.

2. In the Cryptographic Framework feature of Oracle Solaris, an implementation of an algorithm for a particular purpose. For example, a DES mechanism that is applied to authentication, such as CKM_DES_MAC, is a separate mechanism from a DES mechanism that is applied to encryption, CKM_DES_CBC_PAD.

message authentication code (MAC)

MAC provides assurance of data integrity and authenticates data origin. MAC does not protect against eavesdropping.

message digest

A message digest is a hash value that is computed from a message. The hash value almost uniquely identifies the message. A digest is useful for verifying the integrity of a file.


The installation of the minimal operating system that is necessary to run the server. Any software that does not directly relate to the operation of the server is either not installed, or deleted after the installation.

network application server

A server that provides a network application, such as ftp. A realm can contain several network application servers.

network policies

The settings that network utilities configure to protect network traffic. For information about network security, see Securing the Network in Oracle Solaris 11.2 .

nonattributable audit event

An audit event whose initiator cannot be determined, such as the AUE_BOOT event.


Network Time Protocol. Software from the University of Delaware that enables you to manage precise time or network clock synchronization, or both, in a network environment. You can use NTP to maintain clock skew in a Kerberos environment. See also clock skew.


Pluggable Authentication Module. A framework that allows for multiple authentication mechanisms to be used without having to recompile the services that use them. PAM enables Kerberos session initialization at login.


A phrase that is used to verify that a private key was created by the passphrase user. A good passphrase is 10-30 characters long, mixes alphabetic and numeric characters, and avoids simple prose and simple names. You are prompted for the passphrase to authenticate use of the private key to encrypt and decrypt communications.

password policy

The encryption algorithms that can be used to generate passwords. Can also refer to more general issues around passwords, such as how often the passwords must be changed, how many password attempts are permitted, and other security considerations. Security policy requires passwords. Password policy might require passwords to be encrypted with the AES algorithm, and might make further requirements related to password strength.

permitted set

The set of privileges that are available for use by a process.


Generally, a plan or course of action that influences or determines decisions and actions. For computer systems, policy typically means security policy. Your site's security policy is the set of rules that define the sensitivity of the information that is being processed and the measures that are used to protect the information from unauthorized access. For example, security policy might require that systems be audited, that devices must be allocated for use, and that passwords be changed every six weeks.

For the implementation of policy in specific areas of the Oracle Solaris OS, see audit policy, policy in the Cryptographic Framework, device policy, Kerberos policy, password policy, and rights policy.

policy in the Cryptographic Framework

In the Cryptographic Framework feature of Oracle Solaris, policy is the disabling of existing cryptographic mechanisms. The mechanisms then cannot be used. Policy in the Cryptographic Framework might prevent the use of a particular mechanism, such as CKM_DES_CBC, from a provider, such as DES.

policy for public key technologies

In the Key Management Framework (KMF), policy is the management of certificate usage. The KMF policy database can put constraints on the use of the keys and certificates that are managed by the KMF library.

postdated ticket

A postdated ticket does not become valid until some specified time after its creation. Such a ticket is useful, for example, for batch jobs that are intended to run late at night, since the ticket, if stolen, cannot be used until the batch job is run. When a postdated ticket is issued, it is issued as invalid and remains that way until a) its start time has passed, and b) the client requests validation by the KDC. A postdated ticket is normally valid until the expiration time of the ticket-granting ticket. However, if the postdated ticket is marked renewable, its lifetime is normally set to be equal to the duration of the full life time of the ticket-granting ticket. See also invalid ticket, renewable ticket.


The first part of a principal name. See also instance, principal name, realm.


1. A uniquely named client/user or server/service instance that participates in a network communication. Kerberos transactions involve interactions between principals (service principals and user principals) or between principals and KDCs. In other words, a principal is a unique entity to which Kerberos can assign tickets. See also principal name, service principal, user principal.

2. (RPCSEC_GSS API) See client principal, server principal.

principal name

1. The name of a principal, in the format primary/instance@REALM. See also instance, primary, realm.

2. (RPCSEC_GSS API) See client principal, server principal.

principle of least privilege

See least privilege.


A security service, in which transmitted data is encrypted before being sent. Privacy also includes data integrity and user authentication. See also authentication, integrity, service.

private key

A key that is given to each user principal, and known only to the user of the principal and to the KDC. For user principals, the key is based on the user's password. See also key.

private-key encryption

In private-key encryption, the sender and receiver use the same key for encryption. See also public-key encryption.


1. In general, a power or capability to perform an operation on a computer system that is beyond the powers of a regular user. Superuser privileges are all the rights that superuser is granted. A privileged user or privileged application is a user or application that has been granted additional rights.

2. A discrete right on a process in an Oracle Solaris system. Privileges offer a finer-grained control of processes than does root. Privileges are defined and enforced in the kernel. Privileges are also called process privileges or kernel privileges. For a full description of privileges, see the privileges(5) man page.


Programs, scripts, and commands that turn on and off the use of privilege in their code. In a production environment, the privileges that are turned on must be supplied to the process, for example, by requiring users of the program to use a rights profile that adds the privileges to the program. For a full description of privileges, see the privileges(5) man page.

privilege escalation

Gaining access to resources that are outside the range of resources that your assigned rights, including rights that override the defaults, permit. The result is that a process can perform unauthorized operations.

privilege model

A stricter model of security on a computer system than the superuser model. In the privilege model, processes require privilege to run. Administration of the system can be divided into discrete parts that are based on the privileges that administrators have in their processes. Privileges can be assigned to an administrator's login process. Or, privileges can be assigned to be in effect for certain commands only.

privilege set

A collection of privileges. Every process has four sets of privileges that determine whether a process can use a particular privilege. See limit set, effective set set, permitted set set, and inheritable set set.

Also, the basic set set of privileges is the collection of privileges that are assigned to a user's process at login.

privileged application

An application that can override system controls. The application checks for security attributes, such as specific UIDs, GIDs, authorizations, or privileges.

privileged user

A user who is assigned rights beyond the rights of regular user on a computer system. See also trusted users.

profile shell

In rights management, a shell that enables a role (or user) to run from the command line any privileged applications that are assigned to the role's rights profiles. The profile shell versions correspond to the available shells on the system, such as the pfbash version of bash.


In the Cryptographic Framework feature of Oracle Solaris, a cryptographic service that is provided to consumers. PKCS #11 libraries, kernel cryptographic modules, and hardware accelerators are examples of providers. Providers plug in to the Cryptographic Framework, so are also called plugins. For examples of consumers, see consumer.

proxiable ticket

A ticket that can be used by a service on behalf of a client to perform an operation for the client. Thus, the service is said to act as the client's proxy. With the ticket, the service can take on the identity of the client. The service can use a proxiable ticket to obtain a service ticket to another service, but it cannot obtain a ticket-granting ticket. The difference between a proxiable ticket and a forwardable ticket is that a proxiable ticket is only valid for a single operation. See also forwardable ticket.

public object

A file that is owned by the root user and readable by the world, such as any file in the /etc directory.

public-key encryption

An encryption scheme in which each user has two keys, one public key and one private key. In public-key encryption, the sender uses the receiver's public key to encrypt the message, and the receiver uses a private key to decrypt it. The Kerberos service is a private-key system. See also private-key encryption.


Quality of Protection. A parameter that is used to select the cryptographic algorithms that are used in conjunction with the integrity service or privacy service.


Role-based access control, the user rights management feature of Oracle Solaris. See rights.


1. The logical network that is served by a single Kerberos database and a set of Key Distribution Centers (KDCs).

2. The third part of a principal name. For the principal name jdoe/admin@CORP.EXAMPLE.COM, the realm is CORP.EXAMPLE.COM. See also principal name.


The requirement to provide a password to perform a computer operation. Typically, sudo operations require reauthentication. Authenticated rights profiles can contain commands that require reauthentication. See authenticated rights profile.


A configuration variable or relationship that is defined in the kdc.conf or krb5.conf files.

renewable ticket

Because having tickets with very long lives is a security risk, tickets can be designated as renewable. A renewable ticket has two expiration times: a) the time at which the current instance of the ticket expires, and b) maximum lifetime for any ticket. If a client wants to continue to use a ticket, the client renews the ticket before the first expiration occurs. For example, a ticket can be valid for one hour, with all tickets having a maximum lifetime of ten hours. If the client that holds the ticket wants to keep it for more than an hour, the client must renew the ticket. When a ticket reaches the maximum ticket lifetime, it automatically expires and cannot be renewed.

RBAC policy

See rights policy.


An alternative to the all-or-nothing superuser model. User rights management and process rights management enable an organization to divide up superuser's privileges and assign them to users or roles. Rights in Oracle Solaris are implemented as kernel privileges, authorizations, and the ability to run a process as a specific UID or GID. Rights can be collected in a rights profile and a role.

rights policy

The security policy that is associated with a command. Currently, solaris is the valid policy for Oracle Solaris. The solaris policy recognizes privileges and extended privilege policy, authorizations, and setuid security attributes.

rights profile

Also referred to as a profile. A collection of security overrides that can be assigned to a role or user. A rights profile can include authorizations, privileges, commands with security attributes, and other rights profiles that are called supplementary profiles.


A special identity for running privileged applications that only assigned users can assume.


A method for obtaining digital signatures and public key cryptosystems. The method was first described in 1978 by its developers, Rivest, Shamir, and Adleman.

scan engine

A third-party application, residing on an external host, that examines a file for known viruses.


The product name for the initial version of Kerberos on Solaris systems. This product is based on the Kerberos V5 technology that was developed at the Massachusetts Institute of Technology. SEAM is now called the Kerberos service. It continues to differ slightly from the MIT version.

secret key

See private key.

Secure Shell

A special protocol for secure remote login and other secure network services over an insecure network.

security attributes

Overrides to security policy that enable an administrative command to succeed when the command is run by a user other than superuser. In the superuser model, the setuid root and setgid programs are security attributes. When these attributes are applied to a command, the command succeeds no matter who runs the command. In the privilege model, kernel privileges and other rights replace setuid root programs as security attributes. The privilege model is compatible with the superuser model, in that the privilege model also recognizes the setuid and setgid programs as security attributes.

security flavor

See flavor.

security mechanism

See mechanism.

security policy

See policy.

security service

See service.


A numeric starter for generating random numbers. When the starter originates from a random source, the seed is called a random seed.

separation of duty

Part of the notion of least privilege. Separation of duty prevents one user from performing or approving all operations that complete a transaction. For example, in RBAC, you can separate the creation of a login user from the assignment of security overrides. One role creates the user. A separate role can assign security attributes, such as rights profiles, roles, and privileges to existing users.


A principal that provides a resource to network clients. For example, if you ssh to the system, then that system is the server that provides the ssh service. See also service principal.

server principal

(RPCSEC_GSS API) A principal that provides a service. The server principal is stored as an ASCII string in the form service@host. See also client principal.


1. A resource that is provided to network clients, often by more than one server. For example, if you rlogin to the machine, then that machine is the server that provides the rlogin service.

2. A security service (either integrity or privacy) that provides a level of protection beyond authentication. See also integrity and privacy.

service key

An encryption key that is shared by a service principal and the KDC, and is distributed outside the bounds of the system. See also key.

service principal

A principal that provides Kerberos authentication for a service or services. For service principals, the primary name is a name of a service, such as ftp, and its instance is the fully qualified host name of the system that provides the service. See also host principal, user principal.


Secure Hashing Algorithm. The algorithm operates on any input length less than 264 to produce a message digest. The SHA1 algorithm is input to DSA.

single-system image

A single-system image is used in Oracle Solaris auditing to describe a group of audited systems that use the same naming service. These systems send their audit records to a central audit server, where the records can be compared as if the records came from one system.

software provider

In the Cryptographic Framework feature of Oracle Solaris, a kernel software module or a PKCS #11 library that provides cryptographic services. See also provider.

session key

A key that is generated by the authentication service or the ticket-granting service. A session key is generated to provide secure transactions between a client and a service. The lifetime of a session key is limited to a single login session. See also key.

slave KDC

A copy of a master KDC, which is capable of performing most functions of the master. Each realm usually has several slave KDCs (and only one master KDC). See also KDC, master KDC.

stash file

A stash file contains an encrypted copy of the master key for the KDC. This master key is used when a server is rebooted to automatically authenticate the KDC before it starts the kadmind and krb5kdc processes. Because the stash file includes the master key, the stash file and any backups of it should be kept secure. If the encryption is compromised, then the key could be used to access or modify the KDC database.

superuser model

The typical UNIX model of security on a computer system. In the superuser model, an administrator has all-or-nothing control of the system. Typically, to administer the machine, a user becomes superuser (root) and can do all administrative activities.

synchronous audit event

The majority of audit events. These events are associated with a process in the system. A non-attributable event that is associated with a process is a synchronous event, such as a failed login.


An information packet that is used to securely pass the identity of a user to a server or service. A ticket is valid for only a single client and a particular service on a specific server. A ticket contains the principal name of the service, the principal name of the user, the IP address of the user's host, a time stamp, and a value that defines the lifetime of the ticket. A ticket is created with a random session key to be used by the client and the service. Once a ticket has been created, it can be reused until the ticket expires. A ticket only serves to authenticate a client when it is presented along with a fresh authenticator. See also authenticator, credential, service, session key.

ticket file

See credential cache.


Ticket-Granting Service. That portion of the KDC that is responsible for issuing tickets.


Ticket-Granting Ticket. A ticket that is issued by the KDC that enables a client to request tickets for other services.

trusted users

Users whom you have decided can perform administrative tasks at some level of trust. Typically, administrators create logins for trusted users first and assign administrative rights that match the users' level of trust and ability. These users then help configure and maintain the system. Also called privileged users.

user principal

A principal that is attributed to a particular user. A user principal's primary name is a user name, and its optional instance is a name that is used to described the intended use of the corresponding credentials (for example, jdoe or jdoe/admin). Also known as a user instance. See also service principal.

virtual private network (VPN)

A network that provides secure communication by using encryption and tunneling to connect users over a public network.