Gethostbyaddr
The gethostbyaddr DNS query is when the address of a machine is known and the name is needed.

Gethostbyname
The gethostbyname DNS quest is when the name of a machine is known and the address is needed.

GetAdmin
GetAdmin is a well-known cracking tool for Microsoft Windows OS. GetAdmin grants normal user administrative rights by adding them to the Administrators group. This utility can be run from any user context except Guest and grants a local user account administrative rights.

GIAC: Global Information Assurance Certification
Global Information Assurance Certification (GIAC) is a certification program for computer security professionals developed by the SANS Institute.

GINA
GINA is Graphical Identification and Authentication dynamic-link library (DLL). The GINA is a replaceable DLL component that is loaded with the Winlogon executable. The GINA implements the authentication policy of the interactive logon model and is expected to perform all identification and authentication of user interactions.

GLBA:Gramm-Leach-Bliley Act
Gramm-Leach-Bliley Act (GLBA), a US law (Law 106-102) passed on November 12, 1999, contains privacy provisions relating to consumers' financial information. It imposes restrictions on the disclosure of consumers' personal financial information to non-affiliated third parties.

Glitch Attack
Glitch Attack is a method for violating the security of a cryptographic coprocessor (such as a smart card) by disrupting the execution of one or more machine instructions and sequencies. Attacker may inspect the signals generated by the instruction sequence of the circuits and apply an external disturbance at a precise moment when a compare or jump instruction is executing. This effectively blocks the instruction's execution, perhaps bypassing a critical authentication routine. The coprocessor may generate random patterns of sequence to avoid or reduce the risk of the glitch attack.

Global Spy Network
The Global Spy Network named Echelon is an officially unacknowledged U.S.-led global spy network that operates an automated system for the interception and relay of electronic communications. It monitors transmissions including all the telephone calls, e-mail messages, faxes, satellite transmissions, and Internet downloads of both public and private organizations and citizens worldwide.

GnuPG: GNU Privacy Guard
GNU Privacy Guard (GnuPG or GPG) is an open source tool implementing the OpenPGP encryption standard.

GnuTLS: GNU Transport Layer Security Library
GNU Transport Layer Security Library (GnuTLS) is a free software implementation of the SSL and TLS protocols. GnuTLS is primarily licensed under the Lesser GPL; some parts are licensed under the GPL. GnuTLS is comparable to OpenSSL.

GNU
The GNU Project was launched in 1984 to develop a complete UNIX style operating system which is free software: the GNU system. Variants of the GNU operating system, which use the kernel Linux, are now widely used; though these systems are often referred to as “Linux,” they are more accurately called GNU/Linux systems.

Gnutella
Gnutella is an Internet file sharing utility. Gnutella acts as a server for sharing files while simultaneously acting as a client that searches for and downloads files from other users.

Goat
In biometric verification, a goat is a system end-user who is refused access to the system because their biometric data pattern is outside the range recognized by the system. The term comes from a research paper on speech recognition published in 1998 by George L. Doddington.

Goner
Goner is a mass-mailer worm that spread across the Internet in December 2001.

Good Worm
Good worm, also called an ethical worm, is a program that automates network-based distribution of security patches for known vulnerabilities. Like its malicious counterpart, the ethical worm could propagate across networks exponentially and perform its tasks without user knowledge or consent, through a process sometimes called a drive-by download.

Good Times
Good Times is a hoax that poses as an e-mail virus.

Googledork
Googledork refers to those who "troll the Internet for confidential goods." Googledork conveys the concept that sensitive stuff is on the web, and Google can help you find it.

GooPot
GooPot is the Google honeypot system. The GooPot closely resembles the juicy targets that Google hackers typically go after.

Gooscan
Gooscan is a UNIX and alike OS based tool to find vulnerable systems by automating queries against Google and Google search appliances. For the security professional, gooscan serves as a front end for an external server assessment and aids in the information-gathering phase of a vulnerability assessment. For the web server administrator, gooscan helps discover what the web community may already know about a site thanks to Google's search appliance.

GPG: GNU Privacy Guard
The GNU Privacy Guard (GnuPG or GPG) is a free software replacement for the Pretty Good Privacy (PGP) suite of cryptographic software, released under the GNU General Public License. It is a part of the Free Software Foundation's GNU software project. GPG is completely compliant with the IETF standard for OpenPGP.

GPO: Group Policy Object
In the Windows 2000 operating system, a Group Policy Object (GPO) is a collection of settings that define what a system will look like and how it will behave for a defined group of users. Microsoft provides a program snap-in that allows you to use the Group Policy Microsoft Management Console (MMC).

Graphical Password
A graphical password works in an authentication system by having the user selecting an image from images, in a specific order, presented in a graphical user interface (GUI). For this reason, the graphical-password approach is sometimes called graphical user authentication (GUA).

Graphical User Authentication
A Graphic User Authentication (GUA) system works by having the user select from images, in a specific order, presented in a graphical user interface (GUI).

Gray Hat
Gray hat describes a hacker/cracker who exploits a security weakness in a computer system or product in order to bring the weakness to the attention of the owners. Unlike a black hat, a gray hat acts without malicious intent.

Group Policy Object
In the Windows 2000 operating system, a Group Policy Object (GPO) is a collection of settings that define what a system will look like and how it will behave for a defined group of users.

Group Policy
Group Policy is a feature in the Microsoft Windows OS for managing security in Microsoft Windows platforms.

Gsi: Government Secure intranet
Government Secure intranet (GSi) is a UK government organization, whose main purpose is to enable connected organisations to communicate securely, electronically.

GSS: Generic Security Service
Generic Security Services (GSS) is an API in Java based on IETF RFC 2743 and 2744, to provide a layer of abstraction over security mechanisms that perform authentication, message integrity protection, and message privacy protection.

GTAC: Government Technical Assistance Centre
Government Technical Assistance Centre (GTAC) is a United Kingdom organization established at MI5 HQ, which tracks all data traffic passing through their computers.

GUA: Graphic User Authentication
A Graphic User Authentication (GUA) system works by having the user selecting an image from images, in a specific order, presented in a graphical user interface (GUI).