問81
頻出度★★★
マクロウイルスに関する記述として, 適切なものはどれか。
平成21年度 春期 ITパスポート試験 問81
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 81
Incorrectア
Displaying advertisements on the PC screen is a description of “adware.” Adware is software whose purpose is to display advertisements; it is often installed bundled with free software, and malicious versions display large numbers of ads or collect browsing history without the user's consent. It does not have the property inherent to a virus of infecting other files and multiplying, and in that respect it differs from a macro virus.
Incorrectイ
Moving between computers connected over a network while replicating itself is a description of a “worm.” A worm does not parasitize other files; it can exist and act on its own, and it spreads by itself to other computers through networks or email. A macro virus, in contrast, acts only after parasitizing a host document file or spreadsheet file, and the two are distinguished on this point.
Incorrectウ
Freely manipulating another person's PC over a network, or stealing important information such as passwords, is a description of a “Trojan horse” (including backdoor types that enable remote control, as well as bots). It intrudes by disguising itself as useful software and performs unauthorized operations behind the scenes; it does not self-replicate, nor is infecting document files its characteristic.
- エ
正解 The correct answer is エ. A macro virus is a virus created by abusing the “macro” function (a simple program that automatically runs a series of operations) built into word-processing software and spreadsheet software. Because macros can be saved inside document files and spreadsheet files, a macro virus infects not program (executable) files but these “data files” themselves. When an infected file is opened, the embedded macro runs automatically, spreading the infection one after another to other document files or destroying files. Document files are frequently exchanged as email attachments and look safe at first glance, so the damage spreads easily; that is a characteristic of this virus. As countermeasures, in addition to using anti-virus software, the basics are to disable the automatic execution of macros in the application and not to enable macros for files from untrusted senders. Therefore エ, which states that it “infects the data files of word-processing software or spreadsheet software,” is the appropriate description of a macro virus.
ここがポイント
- Macro virus = a virus that abuses an application's macro function (a simple program that automates operations) and infects “data files” such as word-processing and spreadsheet files. The key countermeasure is to disable the automatic execution of macros.
- Identify malware by its characteristics: parasitizes other files and multiplies = virus; replicates itself independently and moves across a network = worm; disguises itself as useful software to perform remote control or steal information = Trojan horse; aims to display advertisements = adware.
用語