What is Mailsafe and how does it work?
ZoneAlarm's MailSafe feature detects e-mail attachments and warns the user about their presence. When a potentially dangerous attachment is detected (POP3 and IMAP protocols), ZoneAlarm "quarantines" it by changing its file extension so that it cannot be executed accidentally with its by default associated software.
For example, a file called TEST.BAT will be renamed TEST.ZL3, should the user chose to "quarantine" files with the BAT extension. That will prevent accidently execution of possible dangerous BAT file which could include malicious code. The file itself is not moved and will remain in its default directory.
These "quarantined" files are not altered, so to restore the file functionality, simple renaming of the Mailsafe extension with its original file extension is sufficient.
List of renamed file extensions used by ZoneAlarm Mailsafe
Originally, ZoneAlarm's Mailsafe included only 37 default file types, that were intercepted in attachments and renamed. These were mostly Windows system files, or files that could contain visual basic or java scripts (like Access databases). These 37 documented files were:
Mailsafe renamed file extensions | Original file extensions |
file extension ZL0 | is renamed ADE file extension |
file extension ZL1 | ADP |
file extension ZL2 | BAS |
file extension ZL3 | BAT |
file extension ZL4 | CHM |
file extension ZL5 | CMD |
file extension ZL6 | COM |
file extension ZL7 | CPL |
file extension ZL8 | CRT |
file extension ZL9 | EXE |
file extension ZLA | HLP |
file extension ZLB | HTA |
file extension ZLC | INF |
file extension ZLD | INS |
file extension ZLE | ISP |
file extension Z0 | JS |
file extension ZLF | JSE |
file extension ZLG | LNK |
file extension ZLH | MDB |
file extension ZLI | MDE |
file extension ZLJ | MSC |
file extension ZLK | MSI |
file extension ZLL | MSP |
file extension ZLM | MST |
file extension ZLN | PCD |
file extension ZLO | PIF |
file extension ZLP | REG |
file extension ZLQ | SCR |
file extension ZLR | SCT |
file extension ZLT | URL |
file extension Z1 | VB |
file extension ZLU | VBE |
file extension ZLV | VBS |
file extension ZLW | WSC |
file extension ZLX | WSF |
file extension ZLY | WSH |
With newer version, more possible dangerous file types were added to the database by default.
Mailsafe file extension | Original file extension |
file extension ZLZ |
is renamed ASX file extension |
file extension ZM0 | DBX file extension |
file extension ZM1 | MDA file extension |
file extension ZM2 | MDZ file extension |
file extension ZM3 | NCH file extension |
file extension ZM4 | PRF file extension |
file extension ZM5 | SCF file extension |
file extension ZM6 | SHB file extension |
file extension ZM8 | MHT file extension |
file extension ZM9 | ZIP file extension |
file extension ZMA | RAR file extension |
file extension ZMB | DLL file extension |
file extension ZMC | EML file extension |
file extension ZMD | OCX file extension |
file extension ZME | SYS file extension |
Because users could also add more file types they want to intercept by MailSafe, the program would continue with the file extension scheme on the renamed files (ZMF, ZMG, ..), but the default types always had the same file extension.