Delegation (computer security)

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Delegation is the process of a computer user handing over its authentication credentials to another user. [1] [2] In role-based access control models, delegation of authority involves delegating roles that a user can assume or the set of permissions that the user can acquire, to other users.

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Types of delegation in IT networks

There are essentially two classes of delegation: delegation at Authentication/Identity Level, and delegation at Authorization/Access Control Level.

Delegation at Authentication/Identity level

It is defined as follows: If an authentication mechanism provides an effective identity different from the validated identity of the user then it is called identity delegation at the authentication level, provided the owner of the effective identity has previously authorized the owner of the validated identity to use his identity. [3]

The existing techniques of identity delegation using sudo or su commands of UNIX are very popular.[ citation needed ] To use the sudo command, a person first has to start his session with his own original identity. It requires the delegated account password or explicit authorizations granted by the system administrator. The user login delegation described in the patent of Mercredi and Frey is also an identity delegation. [4]

Delegation at Authorization/Access Control level

The most common way of ensuring computer security is access control mechanisms provided by operating systems such as UNIX, Linux, Windows, Mac OS, etc. [5]

If the delegation is for very specific rights, also known as fine-grained, such as with Role-based access control (RBAC) delegation, then there is always a risk of under-delegation, i.e., the delegator does not delegate all the necessary permissions to perform a delegated job. This may cause the denial of service, which is very undesirable in some environments, such as in safety critical systems or in health care. In RBAC-based delegation, one option to achieve delegation is by reassigning a set of permissions to the role of a delegatee; however, finding the relevant permissions for a particular job is not an easy task for large and complex systems. Moreover, by assigning these permissions to a delegatee role, all other users who are associated with that particular role get the delegated rights.

If the delegation is achieved by assigning the roles of a delegator to a delegatee then it would not only be a case of over-delegation but also the problem that the delegator has to figure out what roles, in the complex hierarchy of RBAC, are necessary to perform a particular job. These types of problems are not present in identity delegation mechanisms and normally the user interface is simpler.

More details can be found at RBAC.

Related Research Articles

In computer security, an access-control list (ACL) is a list of permissions associated with a system resource (object). An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject and an operation. For instance, if a file object has an ACL that contains (Alice: read,write; Bob: read), this would give Alice permission to read and write the file and give Bob permission only to read it.

In computer systems security, role-based access control (RBAC) or role-based security is an approach to restricting system access to authorized users. It is an approach to implement mandatory access control (MAC) or discretionary access control (DAC).

<span class="mw-page-title-main">Authorization</span> Function of specifying access rights and privileges to resources

Authorization or authorisation is the function of specifying access rights/privileges to resources, which is related to general information security and computer security, and to access control in particular. More formally, "to authorize" is to define an access policy. For example, human resources staff are normally authorized to access employee records and this policy is often formalized as access control rules in a computer system. During operation, the system uses the access control rules to decide whether access requests from (authenticated) consumers shall be approved (granted) or disapproved (rejected). Resources include individual files or an item's data, computer programs, computer devices and functionality provided by computer applications. Examples of consumers are computer users, computer software and other hardware on the computer.

In computing, the superuser is a special user account used for system administration. Depending on the operating system (OS), the actual name of this account might be root, administrator, admin or supervisor. In some cases, the actual name of the account is not the determining factor; on Unix-like systems, for example, the user with a user identifier (UID) of zero is the superuser, regardless of the name of that account; and in systems which implement a role based security model, any user with the role of superuser can carry out all actions of the superuser account. The principle of least privilege recommends that most users and applications run under an ordinary account to perform their work, as a superuser account is capable of making unrestricted, potentially adverse, system-wide changes.

The Unix command su, which stands for 'substitute user', is used by a computer user to execute commands with the privileges of another user account. When executed it invokes a shell without changing the current working directory or the user environment.

<span class="mw-page-title-main">Pluggable authentication module</span> Flexible mechanism for authenticating users

A pluggable authentication module (PAM) is a mechanism to integrate multiple low-level authentication schemes into a high-level application programming interface (API). PAM allows programs that rely on authentication to be written independently of the underlying authentication scheme. It was first proposed by Sun Microsystems in an Open Software Foundation Request for Comments (RFC) 86.0 dated October 1995. It was adopted as the authentication framework of the Common Desktop Environment. As a stand-alone open-source infrastructure, PAM first appeared in Red Hat Linux 3.0.4 in August 1996 in the Linux PAM project. PAM is currently supported in the AIX operating system, DragonFly BSD, FreeBSD, HP-UX, Linux, macOS, NetBSD and Solaris.

In computer security, mandatory access control (MAC) refers to a type of access control by which the operating system or database constrains the ability of a subject or initiator to access or generally perform some sort of operation on an object or target. In the case of operating systems, a subject is usually a process or thread; objects are constructs such as files, directories, TCP/UDP ports, shared memory segments, IO devices, etc. Subjects and objects each have a set of security attributes. Whenever a subject attempts to access an object, an authorization rule enforced by the operating system kernel examines these security attributes and decides whether the access can take place. Any operation by any subject on any object is tested against the set of authorization rules to determine if the operation is allowed. A database management system, in its access control mechanism, can also apply mandatory access control; in this case, the objects are tables, views, procedures, etc.

In computer security, discretionary access control (DAC) is a type of access control defined by the Trusted Computer System Evaluation Criteria (TCSEC) as a means of restricting access to objects based on the identity of subjects and/or groups to which they belong. The controls are discretionary in the sense that a subject with a certain access permission is capable of passing that permission on to any other subject.

Identity management (IdM), also known as identity and access management, is a framework of policies and technologies to ensure that the right users have the appropriate access to technology resources. IdM systems fall under the overarching umbrellas of IT security and data management. Identity and access management systems not only identify, authenticate, and control access for individuals who will be utilizing IT resources but also the hardware and applications employees need to access.

Java Authentication and Authorization Service, or JAAS, pronounced "Jazz", is the Java implementation of the standard Pluggable Authentication Module (PAM) information security framework. JAAS was introduced as an extension library to the Java Platform, Standard Edition 1.3 and was integrated in version 1.4.

sudo Command on Unix systems to temporarily assume root privileges

sudo is a program for Unix-like computer operating systems that enables users to run programs with the security privileges of another user, by default the superuser. It originally stood for "superuser do", as that was all it did, and it is its most common usage; however, the official Sudo project page lists it as "su 'do' ". The current Linux manual pages for su define it as "substitute user", making the correct meaning of sudo "substitute user, do", because sudo can run a command as other users as well.

In computing, privilege is defined as the delegation of authority to perform security-relevant functions on a computer system. A privilege allows a user to perform an action with security consequences. Examples of various privileges include the ability to create a new user, install software, or change kernel functions.

Self-service password reset (SSPR) is defined as any process or technology that allows users who have either forgotten their password or triggered an intruder lockout to authenticate with an alternate factor, and repair their own problem, without calling the help desk. It is a common feature in identity management software and often bundled in the same software package as a password synchronization capability.

In computing, delegated administration or delegation of control describes the decentralization of role-based-access-control systems. Many enterprises use a centralized model of access control. For large organizations, this model scales poorly and IT teams become burdened with menial role-change requests. These requests — often used when hire, fire, and role-change events occur in an organization — can incur high latency times or suffer from weak security practices.

The XTS-400 is a multilevel secure computer operating system. It is multiuser and multitasking that uses multilevel scheduling in processing data and information. It works in networked environments and supports Gigabit Ethernet and both IPv4 and IPv6.

A number of computer operating systems employ security features to help prevent malicious software from gaining sufficient privileges to compromise the computer system. Operating systems lacking such features, such as DOS, Windows implementations prior to Windows NT, CP/M-80, and all Mac operating systems prior to Mac OS X, had only one category of user who was allowed to do anything. With separate execution contexts it is possible for multiple users to store private files, for multiple users to use a computer at the same time, to protect the system against malicious users, and to protect the system against malicious programs. The first multi-user secure system was Multics, which began development in the 1960s; it wasn't until UNIX, BSD, Linux, and NT in the late 80s and early 90s that multi-tasking security contexts were brought to x86 consumer machines.

PERMIS is a sophisticated policy-based authorization system that implements an enhanced version of the U.S. National Institute of Standards and Technology (NIST) standard Role-Based Access Control (RBAC) model. PERMIS supports the distributed assignment of both roles and attributes to users by multiple distributed attribute authorities, unlike the NIST model which assumes the centralised assignment of roles to users. PERMIS provides a cryptographically secure privilege management infrastructure (PMI) using public key encryption technologies and X.509 Attribute certificates to maintain users' attributes. PERMIS does not provide any authentication mechanism, but leaves it up to the application to determine what to use. PERMIS's strength comes from its ability to be integrated into virtually any application and any authentication scheme like Shibboleth (Internet2), Kerberos, username/passwords, Grid proxy certificates and Public Key Infrastructure (PKI).

<span class="mw-page-title-main">OAuth</span> Open standard for authorization

OAuth is an open standard for access delegation, commonly used as a way for internet users to grant websites or applications access to their information on other websites but without giving them the passwords. This mechanism is used by companies such as Amazon, Google, Facebook, Microsoft, and Twitter to permit the users to share information about their accounts with third-party applications or websites.

Security patterns can be applied to achieve goals in the area of security. All of the classical design patterns have different instantiations to fulfill some information security goal: such as confidentiality, integrity, and availability. Additionally, one can create a new design pattern to specifically achieve some security goal.

<span class="mw-page-title-main">Computer access control</span>

In computer security, general access control includes identification, authorization, authentication, access approval, and audit. A more narrow definition of access control would cover only access approval, whereby the system makes a decision to grant or reject an access request from an already authenticated subject, based on what the subject is authorized to access. Authentication and access control are often combined into a single operation, so that access is approved based on successful authentication, or based on an anonymous access token. Authentication methods and tokens include passwords, biometric scans, physical keys, electronic keys and devices, hidden paths, social barriers, and monitoring by humans and automated systems.

References

  1. ↑ Barka, E., Sandhu, R.: A role-based delegation model and some extensions. In: Proceedings of 16th Annual Computer Security Application Conference, New Orleans, U.S.A. (December 2000)
  2. ↑ A mechanism for identity delegation at authentication level, N Ahmed, CD Jensen - Proceedings of the 14th Nordic Conference …, 2009 - portal.acm.org, 2009
  3. ↑ A mechanism for identity delegation at authentication level, N Ahmed, CD Jensen - Proceedings of the 14th Nordic Conference …, 2009 - portal.acm.org, 2009
  4. ↑ Mercredi, Frey: User login delegation. United States Patent Application Publication, US 2004/0015702 A1 2004
  5. ↑ Gollmann, D.: Computer Security 2e. John Wiley and Sons, Chichester (2005)
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