Browse Definitions:

false positive

A false positive is an error in some evaluation process in which a condition tested for is mistakenly found to have been detected. 

In spam filters, for example, a false positive is a legitimate message mistakenly marked as UBE --unsolicited bulk email, as junk email is more formally known. Messages that are determined to be spam -- whether correctly or incorrectly -- may be rejected by a server or client-side spam filter and returned to the sender as bounce e-mail.

One problem with many spam filtering tools is that if they are configured stringently enough to be effective, there is a fairly high chance of getting false positives. The risk of accidentally blocking an important message has been enough to deter many companies from implementing any anti-spam measures at all.

False positives are also common in security systems. A host intrusion prevention system (HIPS), for example, looks for anomalies, such as deviations in bandwidthprotocols and ports. When activity varies outside of an acceptable range – for example, a remote application attempting to open a normally closed port -- an intrusion may be in progress. However, an anomaly, such as a sudden spike in bandwidth use, does not guarantee an actual attack, so this approach amounts to an educated guess and the chance for false positives can be high.

False positives contrast with false negatives, which are results indicating mistakenly that some condition tested for is absent. 

This was last updated in August 2014

Continue Reading About false positive

Join the conversation

1 comment

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

Thanks for sharing these very useful tips for saving too much time which will prove


File Extensions and File Formats

Powered by:


  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces. A...

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...


  • cloud ecosystem

    A cloud ecosystem is a complex system of interdependent components that all work together to enable cloud services.

  • cloud services

    Cloud services is an umbrella term that may refer to a variety of resources provided over the internet, or to professional ...

  • uncloud (de-cloud)

    The term uncloud describes the action or process of removing applications and data from a cloud computing platform.


  • federated identity management (FIM)

    Federated identity management (FIM) is an arrangement that can be made among multiple enterprises to let subscribers use the same...

  • cross-site scripting (XSS)

    Cross-site scripting (XSS) is a type of injection security attack in which an attacker injects data, such as a malicious script, ...

  • firewall

    In computing, a firewall is software or firmware that enforces a set of rules about what data packets will be allowed to enter or...




  • bad block

    A bad block is an area of storage media that is no longer reliable for storing and retrieving data because it has been physically...

  • all-flash array (AFA)

    An all-flash array (AFA), also known as a solid-state storage disk system, is an external storage array that uses only flash ...

  • volume manager

    A volume manager is software within an operating system (OS) that controls capacity allocation for storage arrays.


  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.