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Recommended anti-virus software
Non-supported operating systems
Some recommended precautions against data loss
Do not boot with a floppy disk in the drive
A PC virus is a program that can make a copy of itself and spread from PC to PC, usually without you knowing this. Some viruses deliberately destroy document or data files, others can put silly messages on your screen or otherwise interrupt your work. All who use PCs should take precautions to detect viruses and prevent their spread.
The anti-virus strategy for the University relies on the use of recommended anti-virus software on all PCs and the prompt elimination of viruses that are detected. Certain simple good, virus-aware habits of PC use are also advised. This document gives an overview of Information Services' recommendations.
Announcements and the most up-to-date information are to be found on the Information Services Anti-Virus Web pages at <http://www.bristol.ac.uk/is/computing/advice/virus/>.
The University's Computer Committee has recommended that all departments nominate a local Data Safety Officer to help ensure that adequate safeguards are in place. Data Safety Officers are:
The name of your department's Data Safety Officer can be obtained from the IT Help Desk.
Recommended software to detect and eliminate viruses on PCs running any version of Windows is available free of charge to members of the University from the Anti-Virus pages. Detailed instructions for downloading and installing the software are given there.
Anti-virus software should be updated every term otherwise it will fail to detect all known viruses.
Anti-virus software for microcomputers not running Windows (eg Linux) is not available through Information Services and Information Services cannot help with anti-virus precautions or eliminating viruses from these systems. Some information about non-PC viruses is given on the Anti-Virus pages.
In all cases of difficulty or doubt, consult your department's Data Safety Officer.
Recommended anti-virus software has facilities for eliminating viruses. For further information see the Anti-Virus pages.
If a PC is infected and you are unable or not confident to eliminate the virus yourself, switch off the PC and report the problem to your department's Data Safety Officer, PC support staff, or whoever is responsible for the PC. If the virus is on a shared PC please put a note on it to warn others. The virus may have infected floppy disks used in the PC so check these also. If the virus is in software obtained over a network please inform the person responsible for that network filestore.
If the virus is on a floppy disk or CD do not use these again until the virus has been eliminated. Be aware that the virus may have infected PCs in which the disk or CD has been used. If the infected media was given to you by somebody else then inform them.
If a virus is on a network drive shared by others please immediately report the problem to the person responsible for that network filestore (viruses on shared network drives are potentially very serious).
Please report all virus infections to your Data Safety Officer (whether or not you eliminated the virus yourself).
Certain good habits of PC use reduce the chances that a PC or disks will be infected by viruses in the first place or help avoid loss of data by the actions of a virus or by any other cause. Remember that the most valuable thing about a PC or floppy disk is the data stored on it. A PC or disk can be replaced, but potentially hundreds of hours of work may be irreplaceable.
A backup is a duplicate copy of a file made on removable media (for example, floppy disk or tape). Adequate backups are an essential precaution against any mishap (disk failures and human error as well as viruses).
It is recommended to keep at least two backup copies of any file that is important to you (making three copies in all, counting the original). These copies should all be on different disks and it is a good idea to store one copy well away from the PC, for example at home. A printout is a last resort backup too.
It is not necessary to make backup copies of program files provided you have access to master copies of the programs and are able to re-install them. You may, however, wish to keep copies of configuration files and other files unique to your PC (such as word processor style sheets or templates, glossaries, macros, customised spell-checker dictionaries).
The Information Services' leaflet about Computer 'Housekeeping' includes advice on how to back up. This is available on the Web at <http://www.bristol.ac.uk/is/learning/documentation/housekeep-r1/housekeep-r1.htm>
It is easy to backup a damaged file without realising it has become damaged (some viruses damage files in subtle ways that may not be noticed for a long time). It is not a good idea to always overwrite previous backups (those who maintain databases should be particularly careful as a small corruption could render the entire database worthless!). It is best to archive backups now and again (that is, just put a set away in a safe place and leave them there indefinitely).
Before booting (switching on, resetting) a PC, check that there is no floppy disk in drive A. This simple precaution is the single most effective precaution to avoid infection of the PC by partition sector and boot sector viruses.
If you do accidentally boot with a floppy disk in the drive an error message 'Non system disk or disk error' is displayed and, if the floppy disk was infected, the PC might have become infected. If you see this message you should:
Most modern PCs (for example Viglens) have a facility to disable attempts to boot from floppy disk and this will effectively render the PC immune to partition sector and boot sector viruses. Disabling and re-enabling of floppy booting is done through the system (CMOS) setup. Consult the PC's documentation (for example, Viglen BIOS manual) for details of how to use the system setup.
A virus cannot infect a floppy disk that is physically write-protected. The contents of a write-protected disk are also safe from accidental deletion.
On 3.5in disks there is a slide - when you can see through the hole in the disk it cannot be written to, but when the slide covers the hole it can.
It may be impractical to write-protect floppy disks containing documents or data because you may need to write to them (as when saving files). The following disks, however, should always be write-protected:
Certain activities are more likely to spread viruses than others and awareness of these can help avoid high risk or indicate where particular vigilance is necessary. Do not assume that other people have taken anti-virus precautions on your behalf; the only anti-virus precautions you know for sure have been taken are those you take yourself.
Floppy disks or CDs from any source whatsoever may harbour a virus. Do not assume that if a disk has come from a reputable company, a friend or a colleague then it is virus-free. However the following should be treated with particular suspicion until checked for viruses:
The more people who use a PC, the more likely it is to become infected. The following are particularly open to virus infection and/or likely to cause widespread infection to others if they become infected:
Departments should pay particular attention to administrative PCs. Damage to certain administrative data could be a crippling blow to the running of an entire department and to the University as a whole.
Installing new software is a high-risk activity because file viruses spread in program files. Try to obtain software direct from a reputable source. Public domain software and shareware is often associated in people's minds with viruses, but this is not necessarily helpful. Completely avoiding useful cheap or free software limits your ability to cost-effectively exploit the potential of your PC. If such software is obtained from a reputable source it is no higher risk than any other software. However those who amass free or novelty programs with little regard for whether they are genuinely useful expose themselves to greater risks. The following sources of software are higher-than-average risk:
There are many networks available to University users, for example, various departmental local networks, the UDS, Janet, the Internet (World Wide Web). Networks exacerbate the virus problem because they allow much easier and more widespread distribution of infected software and other files. Obtaining files produced by Microsoft Office applications (eg Word, Excel, PowerPoint) over networks (eg by file transfer, electronic mail, or browsing the World Wide Web) may introduce a virus onto the PC.
In particular be aware that if downloading infectable types of file from remote sites you have no way of knowing if the person in charge of the remote computer thoroughly checked the files before making them available for download. Often you do not know who produced the files (and what anti-virus precautions they took) or their motives for making them publicly available. Many sites do not have the resources to thoroughly check all files they distribute, as is the case with the Higher Educational National Software Archive (HENSA) at Lancaster University. Furthermore some amateur Web sites have the reputation of being high risk.
So far as possible download only from a reputable source unless you think they will be genuinely useful. An up-to-date version of recommended anti-virus software should automatically detect most viruses introduced by network use. See also Precautions against macro viruses and the Data Safety and the Internet section of Anti-Virus pages.
Macro viruses or 'logic bombs' may be present in files created by Microsoft Office applications (eg Word documents, Excel spreadsheets). A good precaution against macro viruses and logic bombs is not to open Microsoft Office files if these are from a source you do not trust (eg attachments to mail messages sent to you by people you do not know, or files downloaded from questionable Web sites).
More generally: