Trojans are malicious applications that pose themselves as legitimate software in order to trick users to install them. Once on the victim's machine, it may run any number of malicious process to steal vital information or inflict damage to other software.
Greetyah downloads a file from the internet and sets an auto-run key in the system registry in order to establish automatic starts.
A mass mailing of this trojan program was detected on March 17th, 2003. Message text appears as follows:
Date: Mon, 17 Mar 2003 14:57:57
To: Ivan Petrov
Subject: Elena_M sent you a Yahoo! Greeting
Surprise! You've just received a Yahoo! Greeting
from from "Elena_M" (firstname.lastname@example.org)!
To view this greeting card, click on the following
Web address at anytime within the next 30 days.
If that doesn't work, go to http://view.greetings.yahoo.com/pickup
and copy and paste this code:
The Yahoo! Greetings Team
c 1996-2003 Yahoo! Greetings http://greetings.yahoo.com/
The program's size is 3072 bytes and is written in the Assembler programming language.
At start the program displays the following message box:
Next the program downloads the file:
from the site:
The file "sysman32.exe" contains the other trojan program:
The trojan program copies this file to the Windows system directory and establishes an auto run key (for automatic starts) in the system registry:
The program also contains the following encrypted strings:
Error Error on line 25: invalid object Do you want to debug? InternetOpenA InternetOpenUrlA InternetReadFile
RegOpenKeyA RegSetValueExA RegCloseKey CloseHandle CreateFileA
GetSystemDirectoryA WriteFile wininet.dll advapi32.dll kernel32.dll