This term was once used to describe a clever programmer. In recent years, this term has been applied to those who exploit security vulnerabilities to try and break into a computer system. Originally, those who break into computer systems (for malicious purposes or as a challenge) were known as ‘crackers’.


A mathematic algorithm that converts a random set of data into a fixed-length line of letters and numbers. The conversion function is called cryptographic hash function, and the result of the conversion is named hash. The algorithm is used for saving paroles, detecting malware etc.

Heap spraying

A technique used in exploits that involves writing a certain sequence of bytes at various places of a heap – a memory that is allocated for use by programs. The technique resembles spray painting a wall to make it all the same color: like a wall, the heap is “sprayed” so that the bytes it contains are uniformly distributed over its entire memory “surface”.

Heuristic analysis

The word heuristic is derived from the Greek ‘to discover’ and refers to a learning method based on speculation or guess-work, rather than a fixed algorithm. In the anti-malware world, heuristic analysis involves using non-specific detection methods to find new, unknown malware. The technique, which has been in use for many years, involves inspecting the code in a file (or other object) to see if it contains suspicious instructions. If the number of suspicious instructions crosses a pre-defined threshold, the… Read Full Article


A hoax is a fake warning about a virus or other piece of malicious code. Typically a hoax takes the form of an e-mail or other message warning the reader of a dangerous new virus and suggesting that the reader pass the message on. Hoaxes cause no damage in themselves, but their distribution by well-meaning people often causes fear and uncertainty. Many anti-malware vendors include hoax information on their web sites and it is always advisable to check before forwarding… Read Full Article


Honeypots are decoy computers used to attract the attention of cyber-attackers. To an attacker, the honeypot seems like a normal part of the computer system, but it’s really segregated from the main system. Honeypots provide a way to deflect attackers from the real network or monitor their activities. Malware honeypots and spam-traps are two kinds of honeypot.


Techniques used to alter or augment the behavior of an operating system, applications or of other software components by intercepting function calls or messages or events passed between software components. Code that handles such intercepted function calls, events or messages is called a hook.

Hosts file

The hosts file is a sort of ‘mini DNS server’ on every Microsoft Windows system. When someone types a URL into the web browser, the browser checks the local hosts file to see if the requested domain name is listed there, before it looks for a DNS server. This is very efficient: if the web browser finds a match in the hosts file, it doesn’t need to go looking on the Internet for a DNS server. Unfortunately, writers of malicious… Read Full Article


A hot spot provides access to a wireless network. Hot spots are now common in businesses, homes, hotels, airports, cafes, fast food outlets, etc.