Summary
This trojan was reportedly distributed with a hacked version of Windows 98. The trojan itself is a DOS EXE file packed with PKLite and named INSTALAR.EXE. The trojan has several text strings in its body that are used to be run as batch commands on certain occasions. The trojan looks for COMSPEC variable and runs COMMAND.COM with /C option and a specific command. The commands are not seen as the trojan redirects output to >NUL.
Removal
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First, check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
Technical Details
When the trojan is run first time, it copies itself as KEYB.EXE to root C:\ folder. The trojan tries to execute 2 batch commands during its initial installation. The first command will copy the trojan to C:\ and the second will run WB32OFF.EXE file if it exists (a disguise?). If it doesn't, the 'Bad command or file name' message appears.
The trojan doesn't modify AUTOEXEC.BAT file to run its copy every time a system starts. But it gets control on Windows systems where keyboard configuration commands are present in AUTOEXEC.BAT (they use KEYB.COM file in \Windows\Command\ folder, but the trojan being in root C:\ folder gains control instead).
After the first reboot the trojan checks system date, creates WB32OFF.TXT file in \Windows\System32\ foder and writes current month and year there as ASCII data, deletes SORT.EXE file, runs KEYB.COM with Spanish keyboard settings and exits. Then it copies KEYB.COM as SORT.COM. Further on the trojan will start SORT.COM and set Spanish keyboard configuration. After some time the trojan will delete KEYB.COM and its file (KEYB.EXE) from C:\ folder and from then on it will be started from \Windows\Command folder.
On the 1st of January 2000 the trojan activates its payload. It deletes all files from disk C:. To speed up the process the trojan tries to start SMARTDRV first.
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