Unsafe attachments of emails may threaten the security of the recipient's data when they are opened. For example, opening an email attachment with extension such as ".exe", ".vbs" or ".scr" causes it to be executed as a program. Executing a malicious program may unleash harmful payloads (e.g. virus, worm, spyware) and may damage/steal your data. Moreover, tricks such as double file extensions (e.g. "readme.doc.exe") may be used to disguise the malicious email attachments.
In order to strengthen the protection against virus/worm/spyware attack (especially for the brand-new virus/worm/spyware that may not be detected by the virus-scanning software), we have enhanced and adopted the standard recommended by Microsoft on restricting the delivery of email with "unsafe attachments". For any email having attachment(s) with any of the following "unsafe file extensions" as listed in Table 1, our mail servers will drop the unsafe attachment or entire email without prior notice.
| .ade
.adp .bas .bat .chm .cmd .com .cpl .crt .exe .hlp .hta .inf .ins .isp .js .jse .lnk .mdb .mde .msc .msi .msp .mst .pcd .pif .reg .scr .sct .shs .shb .url .vb .vbe .vbs .wsc .wsf .wsh |
Microsoft Access project extension
Microsoft Access project Microsoft Visual Basic class module Batch file Compiled HTML Help file Microsoft Windows NT Command script Microsoft MS-DOS program Control Panel extension Security certificate Program Help file HTML program Set up Information Internet Naming Service Internet Communication settings JScript file Jscript Encoded Script file Shortcut Microsoft Access program Microsoft Access MDE database Microsoft Common Console document Microsoft Windows Installer package Microsoft Windows Installer patch Microsoft Visual Test source files Microsoft Visual compiled script Shortcut to MS-DOS program Registration entries Screen saver Windows Script Component Shell Scrap object Shell Scrap object Internet shortcut VBScript file VBScript Encoded script file VBScript file Windows Script Component Windows Script file Windows Script Host Settings file |
Table 1: List of unsafe file extensions
If you need to send an email with an "unsafe attachment" (e.g. ABCD.exe), you should use either one of the following methods and notify your receiver:
Note:
Return to University In-house Email Service FAQ page
IT.ServiceDesk@cityu.edu.hk
