Valid Certificate
Valid Certificate refers to a digital certificate for which the binding of the data items can be trusted; one that can be validated successfully.

VAM: Voice over Internet Protocol
VAM (voice or VoIP spam), also known as SPIT (spam over Internet telephony), is unsolicited bulk messages broadcast over VoIP (Voice over Internet Protocol) to phones connected to the Internet. Although marketers already use voice mail for commercial messages, IP telephony makes a more effective channel because the sender can send messages in bulk instead of dialing each number separately. Internet phones are often mapped to telephone numbers, in the interests of computer-telephony integration (CTI) but each has an IP address as well.

van Eck Phreaking
Van Eck phreaking is a form of eavesdropping in which special equipment is used to pick up telecommunication signals or data within a computer device by monitoring and picking up the electromagnetic fields (EM fields) that are produced by the signals or movement of the data.

VBS.SST
The Anna Kournikova VBS.SST computer virus, informally known as "Anna," is a viral worm that uses Visual Basic to infect Windows systems when a user unwittingly opens an e-mail note with an attachment that appears to be a graphic image of Russian tennis star Anna Kournikova. However, when the file is opened, a clandestine code extension enables the worm to copy itself to the Windows directory and then send the file as an attachment to all addresses listed in your Microsoft Outlook e-mail address book.

Victim host
Victim host, also known as sacrificial lamb, is a server placed outside the firewall with the expectation that it may become compromised.

Virtual Honeynet
A honeynet is a network set up with intentional vulnerabilities to invite attack and identify attackers. Virtual Honeynets simply take the concept of Honeynet technologies, and implement them into a single system, which all the different operating systems have the "appearance" to be running on their own, independent computer. These solutions are possible because of virtualization software that allows running multiple operating systems at the same time, on the same hardware.

Virus
Virus is a hidden, self-replicating section of computer software, usually malicious logic, that propagates by infecting - i.e., inserting a copy of itself into and becoming part of - another program. A virus cannot run by itself; it requires that its host program be run to make the virus active.

Virus Hoax
A virus hoax is a false warning about a computer virus. Typically, the warning arrives in an e-mail note or is distributed through a note in a company's internal network. These notes are usually forwarded using distribution lists and they will typically suggest that the recipient forward the note to other distribution lists.

Virus protection software
Virus protection software, also known as anti-virus software, refers to the software for detecting and removing viruses.

VLAD
VLAD is an open source tool for scanning systems that checks for common security problems. VLAD checks for the items referenced in the SANS Top Ten list of common security problems.

VLAN Hopping
The basic VLAN hopping attack is based on the Dynamic Trunking Protocol and, in some cases, the trunking encapsulation protocol (802.1q or ISL). The Dynamic Trunking Protocol is used for negotiating trunking on a link between two switches or devices and the type of trunking encapsulation to be used.

Voice Logger
A voice logger is a device or program used to record audio information from telephones, radios, microphones, and other sources for storage on a computer's hard drive or removable media. There are two basic modes for recording: vox mode, which is voice-activated, and non-vox mode, in which the recording is continuous.

Voice Spam
Voice spam, also known as VAM (voice or VoIP spam) or SPIT (spam over Internet telephony), is unsolicited bulk messages broadcast over VoIP (Voice over Internet Protocol) to phones connected to the Internet. Although marketers already use voice mail for commercial messages, IP telephony makes a more effective channel because the sender can send messages in bulk instead of dialing each number separately. Internet phones are often mapped to telephone numbers, in the interests of computer-telephony integration (CTI) but each has an IP address as well.

Voiceprint
A voiceprint is a set of measurable characteristics of a human voice that uniquely identifies an individual. These characteristics, which are based on the physical configuration of a speaker's mouth and throat, can be expressed as a mathematical formula. The term applies to a vocal sample recorded for that purpose, the derived mathematical formula, and its graphical representation. Voiceprints are used in voice ID systems for user authentication.

Vomit
Vomit (spelled all lower-case) is a Unix software utility that takes IP telephony packets captured by another Unix tool, tcpdump, and reassembles them into a Wave file that can be listened to over a computer's speakers. Although vomit can be used for network debugging or as a speaker-phone utility, it is most often associated with VoIP eavesdropping attacks.

VPN: Virtual Private Network
Virtual Private Network (VPN) refers to simulating a private network over the public Internet by encrypting communications between the two private end-points. This provides the same connectivity , QOS and privacy you would find on a typical private network.

Vulnerability
Vulnerability refers to a flaw or weakness in a system's design, implementation, or operation and management that could be exploited to violate the system's security policy.

Vulnerability assessment
Vulnerability assessment is the process of identifying and quantifying vulnerabilities in a system. The system being studied could be a physical facility like a nuclear power plant, a computer system, or a larger network. Vulnerability assessment can be done by manual processes or using some automated tools such as Vulnerability scanners.

Vulnerability cryptanalysis
Vulnerability cryptanalysis refers to the science of finding methods for breaking crypto-systems.

Vulnerability Disclosure
Vulnerability disclosure is the practice of publishing information about a computer security problem, and a type of policy that stipulates guidelines for doing so. Either the person or organization that discovers the vulnerability or a responsible industry body such as the Computer Emergency Readiness Team (CERT) may make the disclosure; sometimes after alerting the vendor and allowing them a certain amount of time to fix the problem before publishing the information.

Vulnerability Scanner
A vulnerability scanner is a type of computer program specifically designed to search a given software or hardware system for security weaknesses. The scanner systematically engages the target in an attempt to assess where the target is vulnerable to "attacks". The program can be used either prophylactically (to find holes and plug them before they are exploited) or maliciously (to find holes and exploit them).

Vulnerability Scanning
Vulnerability Scanning is the process of using some software or hardware tools to identify vulnerabilities of computing systems in a network in order to determine if and where a system can be exploited and/or threatened. Vulnerability scanning seeks out security flaws based on a database of known flaws, testing systems for the occurrence of these flaws and generating a report of the findings that an individual or an enterprise can use to tighten the network security.