問68
頻出度★★★
アドウェアに関する記述として, 適切なものはどれか。
平成24年度 秋期 ITパスポート試験 問68
テクノロジ系セキュリティ › 情報セキュリティ
This question's explanation and your answers so far.
解説
問 68
- ア
正解 The correct answer is ア, “It displays advertisements on the PC screen.” Adware is a word formed by combining advertisement and software, and just as the name says, it is software whose main function is to display advertisements on the user's PC screen. Originally it was used as a business model: in exchange for providing software free of charge, ads were shown in part of the screen or in pop-ups, and the advertising revenue covered the development costs. Adware that presents the conditions for displaying ads to the user in advance and obtains consent is legitimate software. On the other hand, there are also many malicious kinds that slip in without the user clearly agreeing, for example by being bundled with the installer of a free program, and that keep throwing up pop-up ads one after another even when closed, rewrite the browser's home page or search engine without permission, and make uninstallation difficult. Furthermore, some types collect browsing history and search keywords without the person's permission and send them outside in order to target the ads; in that case they also have the character of spyware, so they are treated as a kind of malware (malicious software). In any case, what characterizes adware is the point that it “displays advertisements”, and ア, which states that definition as it is, is appropriate.
Incorrectイ
“It moves between computers connected over a network while replicating itself” is a description of a worm. A worm does not need to attach itself to another program and can operate on its own; it makes copies of itself and spreads the infection to one computer after another by way of networks, e-mail, shared folders, and so on. This explosive self-propagation is its characteristic, and it works in a completely different way from adware, whose purpose is to display advertisements.
Incorrectウ
“It remotely manipulates other people's PCs over a network, or steals important information such as passwords” is a description of bots and backdoor-type Trojan horses, which make remote control possible, and of spyware, which steals information. An infected PC is turned into a stepping stone (a member of a botnet) that acts on the attacker's commands, and it may also be abused for sending out large volumes of spam or for DDoS attacks. Some adware does collect browsing history, but freely operating another person's PC or stealing passwords is not taken as the definition of adware.
Incorrectエ
“It infects the data files of word processing software or spreadsheet software” is a description of a macro virus. A macro virus is created by abusing the macro function (a simple program that automates operations) that can be embedded in document files and spreadsheet files; infection takes place at the moment the file is opened and the macro is run, and after that it spreads to other documents created with the same software. Its characteristic is that what it infects is not a program file but a data file, which makes it something different from adware, whose purpose is to display advertisements.
ここがポイント
- Definition of adware — a word combining advertisement and software, it is software whose main function is to display advertisements on the screen. Some are legitimate, showing ads with consent in return for being provided free of charge, but ones that are installed without permission and keep displaying ads, or that collect browsing history without permission in order to deliver ads and so behave like spyware, are treated as malware.
- Telling malware types apart by behavior — what replicates itself and spreads over a network is a worm; what attaches to other programs to multiply is a virus (and among these, the one that abuses macros in data files is a macro virus); what sneaks in disguised as useful software and carries out remote control or information theft is a Trojan horse, a bot, or spyware; and what aims to display advertisements is adware.
用語