ALIAS: HLLM.Seoul, Korvar, I-Worm.Winevar, Braid.C
THIS VIRUS IS RANKED AS LEVEL 2 ALERT
UNDER F-SECURE RADAR
For more information, see
The Winevar e-mail worm was found in-the-wild in Korea in the end of November 2002. Apparently it was released on purpose during the AVAR 2002 Conference (Anti-Virus Researcher's Asia) in Seoul, South Korea.
The worm's file is a Windows PE executable about 91Kb long. The worm was written in Microsoft Visual C++. It should be noted, that Winevar resembles Bridex worm that appeared earlier. The Winevar worm has many bugs that can cause damage to infected systems and limit the worm's spreading.
When the worm's file is run, it copies itself as WINxxxx.PIF file (xxxx - random characters) to Windows System directory. It creates startup keys for this file in the System Registry:
After that the worm creates a dropper for Funlove.4099 virus as WINxxxx.PIF file (xxxx - random characters) to Windows System directory. The original text is replaced with the following line:
~AAVAR 2002 in Seoul~
The original Funlove's dropper name (FLCSS.EXE) is replaced with AAVAR.PIF filename. The description of Funlove virus is here:
Being active the Winevar worm continuosly looks for and terminates processes and services that contain the following text:
However, the worm doesn't kill the above mentioned processes and services if the following text is present in them:
The worm scans hard drives for files and folders with the following text in their names:
If such folder or file is found, the worm attempts to delete all files in that folder. Due to a bug in this routine, the worm deletes all files on an infected hard drive.
To get e-mail addresses the worm looks for *.HTM and *.DBX files and extracts emails addresses from them. The worm ignores e-mail addresses with the following text: '@microsoft' to prevent its spreading to Microsoft. To send infected messages the worm uses a direct connection to a default SMTP server.
The worm stores e-mail addresses to where it already sent itself in the following Registry key:
An infected e-mail message looks like that:
Subject: Re: AVAR(Association of Anti-Virus Asia Reseachers)
AVAR(Association of Anti-Virus Asia Reseachers) - Report.
Invariably, Anti-Virus Program is very foolish.
Attached file names:
WINxxx.TXT (12.6 KB) MUSIC_1.HTM
WINxxx.GIF (120 bytes) MUSIC_2.CEO
The 'xxx' represents random characters. In some cases the subject and message body can be different. The .CEO and .PIF files are the same and represent the worm's executable file.
The .HTM file contains the VM ActiveX Component exploit. It contains a script that will add .CEO extension to the Registry and associate it with executable files. So a user will be able to run files with CEO extensions as executables. This is a security hole and we recommend to add this extension to the list of scanned extensions of F-Secure Anti-Virus if it's not present there yet.
To run from an infected message the worm uses the Iframe exploit, that is widely used in present day e-mail worms. The IFrame vulnerability is fixed and the patch for it is available on Microsoft's website:
Also the worm uses Microsoft VM ActiveX Component vulnerability:
In case the worm fails to spread and or in case of file deletion payload activation, it displays a messagebox:
Make a fool of oneself
What a foolish thing you have done!
The worm continuosly tries to download the front page of www.symantec.com
website to a temporary file, then deletes this file. This might create a DoS (Denial Of Service) attack in case the worm becomes widespread.
Winevar attempts to copy itself as EXPLORER.PIF to a desktop folder. The worm also contains code, that looks like an incomplete network spreading routine.
The worm changes Windows registration information on an infected computer:
Registered Organization: Trand Microsoft Inc.
Registered Owner: AntiVirus
Winevar creates a mutex for itself with the following name:
~~ Drone Of StarCraft~~
F-Secure Anti-Virus detects Winevar worm with the updates published on November 25th, 2002:
[Analysis: F-Secure Corporation and Kaspersky Labs; November 24-25th, 2002]